Search

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The cold rolling behavior of ferritic stainless steel was investigated via crystal plasticity analysis to clarify the effects of initial orientation and neighboring grain interaction on grain rotation and fragmentation behaviors. The analysis revealed that the {112} < 110 > orientation grain tends to maintain its initial orientation after cold rolling. However, the {110} < 001 > orientation grain completely disappeared at 80% cold rolling thickness reduction. The {110} < 001 > orientation grain had high deformation sensitivity. The four initial orientation grains tend to rotated toward the line connecting < 001 > and < 111 > , eventually stabilizing at < 111 > //normal direction (ND). Grains rotate in the following path: < 117 > → < 113 > → < 112 > → < 223 > → < 111 >. The dislocation density is different between grains near the grain boundary region and those farther away. The near < 111 > //ND deformation microstructure region has a lower dislocation density compared to the region near < 110 > //ND. Furthermore, the {111} < 110 > orientation grain exhibited significant grain fragmentation, while the {001} < 110 > orientation grain eventually forms the < 110 > //rolling direction (RD) deformation microstructure without significant fragmentation. The initial orientation {110} < 001 > grain resulted in a double fiber deformation texture with < 111 > //ND and < 110 > //RD orientations. This grain has grain fragmentation features corresponding to the initial {111} < 110 > and {001} < 110 > orientations. These findings are important for understanding the deformation behavior of grains in polycrystalline materials, as well as for designing high-performance metals by controlling the initial microstructure during cold rolling. [ABSTRACT FROM AUTHOR]

In order to enhance the formability and ridging resistance of Sn microalloyed ferritic stainless steel (FSS), an investigation was conducted on the texture and microstructure evolution, as well as formability and surface ridging of Sn microalloyed FSS at various hot rolling finishing temperatures (HRFTs). This study employed x-ray diffraction, optical microscopy, electron backscattering diffraction, tensile testing, and surface roughness measurement techniques. Hot-rolled sheets with HRFTs of 940, 870, 800, and 730 °C were subjected to annealing at 950 °C for 5 min and cold rolling at a reduction of 80%. Subsequently, they were annealed at 900 °C for 2 min. The research indicates that decreasing the HRFT has a positive impact on reducing {001} <110> grains and its texture intensity. Additionally, it leads to microstructure refinement and intensification of <111> //ND (ND: normal direction), thereby improving formability and resistance against ridging. When the HRFTs are within the range of 940–730 °C, the final sheet with an HRFT of 800 °C exhibits optimal formability and surface quality due to the formation of fine recrystallized <111> //ND grains with a sharp texture intensity. In comparison to the final sheet produced through conventional hot rolling with an HRFT of 940 °C, the average r value for the final sheet with an HRFT of 800 °C is increased by 19.4%, while the ridging height is reduced by 46.5%. This demonstrates the significance of reasonable optimization of the hot rolling process in enhancing the formability and ridging resistance of Sn microalloyed FSS. [ABSTRACT FROM AUTHOR]

Exhaust gas recirculation (EGR) coolers are standard accessory items to reduce internal combustion engine emissions and fuel consumption. These coolers are composed of stainless steel brazed with Ni-based brazing filler metals that can internally withstand high exhaust gas temperatures and corrosive environments. In this study, the corrosion behavior of the SUS444 joint brazed with MBF67 foil was examined by an anodic polarization measurement in hydrochloric acid and was compared with that of the SUS444 joint brazed with MBF20 foil. The result indicated that the SUS444 joint brazed with MBF67 showed corrosion with a much higher potential in the polarization curve than the SUS444 joint brazed with MBF20. The reason for the high potential was concluded that the Cr-depleted zone was not formed at the boundary layer between the SUS444 and MBF67 because of low B in MBF67, and the high phosphorus--containing (Ni, Cr)-P eutectic phase with high corrosion resistance remained at the brazed layer because of high P in MBF67 [ABSTRACT FROM AUTHOR]

Due to the recurrent starting and stopping operations of automobiles during service, their engines' hot ends are continually subjected to high-temperature cyclic oxidation. Therefore, it is crucial to develop ferritic stainless steels with better high-temperature oxidation resistance. This study focuses on improving the high-temperature cyclic oxidation performance of 18Cr-Mo (444-type) ferritic stainless steel by alloying with high-melting-point metal W and the rare earth element Ce. For this purpose, a high-temperature cyclic oxidation experiment was designed to simulate the actual service environment and investigate the high-temperature cyclic oxidation behavior and microstructure evolution of 444-type ferritic stainless steel alloyed with W and Ce. The oxide structure and composition formed during this process were analyzed and characterized using scanning electron microscopy/energy dispersive spectroscopy (SEM-EDS) and electron probe X-ray micro-analyzer (EPMA), in order to reveal the mechanism of action of W and Ce in the cyclic oxidation process. The results show that 18Cr-Mo ferritic stainless steel alloyed with W and Ce exhibits an excellent resistance to high-temperature cyclic oxidation. The element W can promote the precipitation of the Laves phase between the matrix and the oxide film, and the small-sized Laves phase can inhibit the interfacial diffusion of oxidation reaction elements and prevent the inward growth of the oxide film. The element Ce can refine oxide particles and reduce the thickness of the oxide film. CeO2 particles within the oxide film can serve as nucleation sites for the formation of oxide particles from reactive elements, and they also contribute to pinning the oxide film, thereby enhancing its adhesion. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the companion paper, test results were presented to explore the flexural performance of cold-formed ferritic stainless steel (FSS) closed built-up beams. Each specimen was fabricated by joining two lipped channels in a face-to-face configuration and securing them with spot welds at intermediate points along the beam span. Sectional aspect ratio, compression flange's sectional slenderness and moment gradient were the key parameters varied to explore their influence on the flexural response of such members through tests. The current paper establishes a simplified finite element (FE) model of cold-formed FSS closed built-up beams and verifies it against the test results. Further, an extensive parametric study is carried out using the validated FE model to generate a large pool of data points. A wider database comprising of test results, numerical results obtained from this study and numerical results available in the companion paper were used to critically examine the adequacy of the current Australian Specifications (AS/NZ), American Standard (SEI/ASCE-8), European Code (EN 1993-1-4), Modified Eurocode approach suggested by Gardner and Theofanous, and Direct Strength Method (DSM) in North American Specification (AISI-S100: 2016), Modified DSM approach proposed by the authors in the literature and Continuous Strength Method (CSM) for cold-formed steel (CFS) flexural members. This makes the current study the first to extensively assess the accuracy of the various design guidelines available in the codes and other relevant literature, which explicitly highlighted their grave limitations. Accordingly, through suitable modifications and recommendations, new design rules are proposed to reliably and safely predict the flexural capacity of cold-formed FSS closed built-up beams. [ABSTRACT FROM AUTHOR]

Stainless steel is used as a heat-resistant material not only in air, but also in carburizing atmospheres containing CO and CO2. Carburization may cause austenization for ferritic stainless steels. In this study, the high-temperature oxidation behaviors of 17％ Cr ferritic stainless steels with and without the addition of austenite-forming elements, such as Cu and Ni, in a carburizing atmosphere at 1123K were investigated. The steels did not exhibit breakaway oxidation in the temperature range of 1123-1273K in air. However, doping the steels with Cu and Ni enhanced breakaway oxidation in a carburizing atmosphere at 1123 K. Traces of austenization and carburization were observed at the base metal under the breakaway oxidation scale of the 17％ Cr steel doped with 1％ Cu and 1％ Ni. Thus, it is proposed that the breakaway oxidation of the ferritic stainless steels in a carburizing atmosphere is attributed to austenization induced by carburization and doping with austenite-forming elements. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present research used the DC electrodeposition method to apply an Mn–Co–ZrO2 composite coating on the steel interconnect plates of solid oxide fuel cells. The surface morphology and phase structure of the obtained coating were investigated using a field emission scanning electron microscope (FESEM) equipped with an EDS analyzer and an XRD device, respectively. The isothermal oxidation behavior of the samples was also studied by measuring their weight changes after 500 h oxidation at 800 °C. The results of isothermal oxidation showed that the oxidation rates of the coated and uncoated samples were of the order of 10−14 g2 cm−4 s−1 and 10−13 g2 cm−4 s−1, respectively. XRD analysis confirmed the presence of highly electrically conductive spinels (MnCo2O4 and Co3O4) and ZrO2 particles in the oxidized coating. In contrast, it proved the presence of spinels with low electrical conductivity (FeCr2O4 and MnCr2O4) in the oxide scale on the uncoated sample. [ABSTRACT FROM AUTHOR]

The research investigates the mechanical and corrosion behavior of Cr-Si-S-C ferritic stainless steel (FSS), known as EN1.4105, which is equivalent to AISI430F. The static isothermal recrystallization annealing is applied to the cold-drawn (CD) materials with two different reduction rates (RRs) of 20 and 35%, under various conditions of soaking temperature and incubation time, which provide 42 unique specimens. The microstructures of CD and annealed materials are characterized by using the electron backscatter diffraction method. X-Ray diffraction analysis alongside scanning electron microscopy linked with energy-dispersive X-ray spectroscopy are also employed to scrutinize the precipitation of any secondary phases, morphologies, and the related chemical compositions. Two different corrosive chlorinated and acidic electrolyte solutions are used for the potentiostatic-based corrosion tests to investigate the passivation kinetics. The results show that the higher RR, which provides faster recrystallization, results in a higher scale of non-hardenable materials. In addition, the effects of RR and annealing conditions are found to have an impact on the corrosion resistance. Moreover, the material exhibits varied behavior in terms of both passivation layer formation as the immersion in the sulfuric acid electrolyte solution (SAES) and active electrochemical behavior immersing in sodium chloride electrolyte solution (SCES). However, this material shows lower corrosion current density and higher corrosion potential in the SCES compared to the SAES medium. The comprehensive findings underscore the intricate relationship between reduction rates, annealing conditions, microstructural evolution, and corrosion behavior in this FSS. The observed trends provide valuable insights for optimizing material performance and corrosion resistance in practical applications. [ABSTRACT FROM AUTHOR]

Ferritic stainless steel (FSS) is widely used to manufacture deep-drawn products for corrosion resistance applications, being the alloy drawability strongly affected by its microstructural anisotropy. This study combines a variety of microscopy techniques enabling in-depth analyses of the microstructural evolution of two different FSSs correlated to their deep drawing performance. One of the steels has a good correspondence with the standard EN-1.4016 (AISI 430). The other is a modified version of the previous one with higher contents of the ferrite-stabilising elements Si and Cr, and lower contents of the austenite-stabilising elements C, N, and Mn. Electron Backscatter Diffraction results confirm that the microstructural properties and drawability of FSS in the deep drawing process are improved in the modified steel version. Scanning transmission electron microscopy under low-angle annular dark field conditions evidences that the deformation mechanism of FSS during deep drawing follows a microstructural distortion model based on the grain size gradient and shows a variation of the deformation texture depending on the alloy composition. This work demonstrates the potential of advanced microscopy techniques for optimising the processing and design of ferritic stainless steels, with slight variations in the alloy composition, for deep drawing applications. [ABSTRACT FROM AUTHOR]

The rolling process is crucial in the process design for achieving good formability of ferritic stainless steel. A comparison is made between hot rolling and cold rolling, and the influence of reduction distribution between hot and cold rolling on the evolution of microstructure and texture is discussed. The results indicate that the partitioning of a high cold-rolling reduction rate is better than the hot rolling in terms of microstructure and properties. With increasing thickness reduction via cold rolling, {223}<110> component in cold-rolled sheets exhibits a progressive strengthening, while {111} <121> component becomes more intense and the degree of deviation from the ideal γ-fiber axis is weakened after annealing. The increase in cold deformation refines the microstructure and increases the fraction of <111> //ND-oriented grains. Therefore, ferritic stainless steels with higher cold-working render an excellent combination of strength and formability. [ABSTRACT FROM AUTHOR]

More and more cars are installing urea selective catalytic reduction (SCR) systems to solve the problem of exhaust emissions, which often operates at high temperatures in the exhaust system and is prone to failure of the exhaust pipe due to high-temperature oxidation. And niobium containing ferritic stainless steel has been widely used in the manufacturing of automotive exhaust pipes. In order to extend the service life of ferrite stainless steel exhaust pipes, niobium plays a crucial role as an added alloying element. The solid solution and precipitation of niobium in ferritic stainless steel will give ferritic stainless steel more excellent high temperature resistance. The precipitation of Nb can change the organizational structure in steel and refine the grains. However, if the content is not properly controlled, large particles of (Nb, Ti) C will precipitate, which will reduce the high temperature oxidation resistance. In this paper, the high temperature oxidation behavior of two kinds of ferritic stainless steels with different Nb content at 700 °C, 800 °C and 900 °C was studied. The microstructure of the oxide film on the surface of the material, the thickness of the oxide layer on the cross section, the distribution of chemical composition, the existence form and distribution of Nb element were analyzed by SEM, EDS, XRD and TEM. The results show that the higher the niobium content, the better the high temperature oxidation resistance, and the higher the temperature, the more obvious the high temperature oxidation resistance of niobium. This is because the high Nb content steel is easy to precipitate NbN and other Nb-containing precipitates at the grain boundary, which is helpful to the high temperature resistance. In the case of less Nb content, its ability to generate (Nb, Ti) C precipitates and coarsen at high temperatures reduces its high-temperature resistance. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The powder bed fusion–laser beam (PBF-LB) process, a method of additive manufacturing (AM), was used to print duplex stainless steel (DSS) using commercial-grade 2507 powders. While conventionally processed DSS has a two-phase microstructure consisting of 50% austenite and 50% ferrite, the PBF-LB-printed 2507 alloy was nearly 100% ferrite. Optimal processing conditions that minimized porosity were determined to be 290 W laser power and 1000 mm/s scan speed, and grain size, texture, and phases were characterized as a function of laser power and scan speed. Grain size increased with increasing laser power but decreased with increasing scan speed. A <100> texture diminished with increasing scan speed from 1000 mm/s to 1400 mm/s. No austenite phase was detected. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) characterization revealed nanoscale chromium nitride precipitates in the ferritic matrix (incoherent hexagonal close-packed (HCP) precipitates at grain boundaries and coherent body-centered cubic (BCC) precipitates within the grains) and a high density of tangled dislocations. Tensile tests of as-printed alloys showed a yield strength of 570 MPa, an ultimate tensile strength of 756 MPa, and an elongation to failure of 10%. The tensile properties were analyzed based on the observed microstructure considering grain size, nanoscale precipitates, and the high density of dislocations. [ABSTRACT FROM AUTHOR]

A self-designed ultrasonic-assisted welding platform was built to improve the poor microstructure and properties of conventional TIG welded ferritic stainless steel. The ultrasonic vibration was transmitted to the weld pool through the base metal in the manner of point–surface contact in the optimal position after calculation. The results show that the coarse columnar grains in the welded joint can be transformed into very fine equiaxed grains under ultrasonic vibration, especially the coarse columnar grains near the fusion line where cliff-like refinement occurs. The maximum grain size in the weld seam is reduced from 420 μm to 260 μm, and the average size is reduced by 60%. At the same time, the grain orientation tends to be harmonized. The microhardness of the welded joint is greatly improved on the whole, and the softening of the heat-affected zone caused by grain coarsening is effectively inhibited. Compared with the welded joints without ultrasonic assistance, the tensile strength and yield strength can be increased by 61 MPa and 47 MPa, respectively, under 130 W ultrasonic vibration. By strengthening the weak part of the welded joint, the weldability and toughness reserve of 441 ferritic stainless steel can be significantly improved. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The current work investigates the relationship between the crack growth rate (CGR) and the cyclic crack‐tip opening displacement (ΔCTOD) of microstructurally small fatigue cracks by using high‐resolution digital image correlation (DIC). Load‐controlled fatigue tests were conducted on small‐scale specimens of 18%Cr body‐centered cubic ferritic stainless steel. Microstructurally small fatigue crack growth was analyzed based on accurate high sample‐rate measurements, starting from a sub‐grain crack length up to seven times the volume‐weighted grain size dv = 224 μm. Under these experimental conditions, the high‐resolution analyses reveal that variation from the otherwise linear relationship between CGR and ΔCTOD on double logarithmic scale is due to the crack‐tip bypassing an inhomogeneous shear strain localization zone. In this zone, ΔCTOD is not able to characterize the behavior of microstructurally small fatigue cracks. Outside the shear strain localization zone, ΔCTOD still is a valid crack driving force parameter. Highlights: Crack tip opening displacement range ΔCTOD and CGR show mostly linear relationship.ΔCTOD and CGR relationship becomes non‐linear if shear strain accumulation is present.If the crack tip penetrates the hardened region, CGR decreases.Strain accumulation is influenced by grain orientation and grain size. [ABSTRACT FROM AUTHOR]

The plasticity of welded 441 ferritic stainless steel joints was controlled by varying the laser beam spot diameter during laser welding. A stainless steel plate thickness of 1.2 mm was used. The microstructures of the welded joints were analyzed for various spot diameters. The elongation of breaks and the reduced area of tensile specimens were analyzed to study the effects of spot diameter on plasticity of the welded joints. The results showed that the weld melt width and weld column crystal size increased with the spot diameter, but isometric crystals in the center of the weld were gradually reduced. Increasing spot diameter resulted in decreased tensile strength, elongation after breaks, and area reduction. So the parameter must be controlled during the laser welding. [ABSTRACT FROM AUTHOR]

The corrosion behavior of a ferritic unstabilized stainless steel 1.4016 during decomposition of aqueous urea solution at high temperature has been investigated. Corrosion was obtained from 100 h of cyclic heating (from room temperature up to 600 °C) and injection of aqueous urea solution on the steel plate in a laboratory-scale test bench. The evaluation procedure covered the metallographic analysis of corroded steel samples by high-resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (TEM). Uniform corrosion underneath deposits was found as one of the drivers for degradation of the steel. Damage happened by high-temperature depassivation of stainless steel due to the excess of the aggressive medium. Besides uniform corrosion, a nitridation layer underneath surface oxides together with chromium carbonitride particles precipitated through the whole depth of the sample was identified resulting in intergranular attack. [ABSTRACT FROM AUTHOR]

An investigation was designed to research the effect of molybdenum (Mo) content on the microstructure and properties of novel ferritic stainless steel (FSS) fabricated by laser melting deposition (LMD). In this study, the stainless steel specimens with different Mo content were manufactured using LMD and the microstructures, the microhardness, wear resistance and corrosion resistance of the as-deposited specimens were evaluated. Experimental results demonstrated that the phase composition of the specimens had no change and consisted of α-Fe and carbide M7C3 phase. The typical dendrite and interdendrite structures were observed, and the grains are obviously refined with the increase of Mo element. The microhardness value of as-deposited specimens increased from 643 to 803 HV, and the specific wear rate was reduced from 1.14 × 10−5 to 5.90 × 10−6 mm3/Nm, correspondingly one order of magnitude reduction, which verified that the wear resistance was obviously improved. The corrosion current density of FSS-Mo is two orders of magnitude lower than that of FSS, and it shows better impedance parameters, indicating that the addition of Mo can effectively improve the electrochemical corrosion performance of materials. [ABSTRACT FROM AUTHOR]

Copyright of Materials Protection (0351-9465) is the property of Engineers Society for Corrosion Republic of Serbia, Belgrade and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effects of alloy elements (Cr, Mn, Cu, Si, Al, Ni, and Ce) on the anti-corrosion behavior and soft magnetic properties of ferritic stainless steel were studied. The results show that the increasing content of Cr, Mn, Cu, and Si ameliorate anti-corrosion behavior, and among the alloy elements, Cu is the most effective to enhance corrosion resistivity. Conversely, the anti-corrosion performance deteriorates with increasing Al and Ce content, despite still maintaining good corrosion resistance overall. Furthermore, in regard to the soft magnetic properties, the regulatory mechanism is more complex and the addition of Cu, Si, and Ce can improve the soft magnetic properties, while their content should be limited. The augmentation of Cr deteriorates the soft magnetic properties, while the increase of Al proves advantageous. Meanwhile, Ni is effective to improve the soft magnetic properties; however, it does not significantly enhance the corrosion resistance, and considering its cost, it is not a necessary element to add. With the optimal composition, the alloy exhibits superior anti-corrosion behavior and softer magnetic properties compared to the commercial grade steel, which can contribute to expanding the applications of ferritic stainless steel. [ABSTRACT FROM AUTHOR]

The evolution of Co coating in solid oxide fuel cells (SOFCs) under low and medium temperatures (<700 °C) is different from that under high temperatures. In this context, the oxidation corrosion of 441 ferritic stainless steel (FSS) with a Co coating in air under 650 °C was investigated. The results indicated that the Co coating was oxidized rapidly and a Co3O4 spinel layer formed in the initial exposure of 5 min, which improved the oxidation resistance of 441 steel. After oxidation at 650 °C for 120 h, a Cr2O3 layer with a thickness of 0.2–0.4 μm was observed on the surface of bare 441 steel, while the surface oxide scale of Co-coated 441 steel samples was composed of an inner Cr2O3 and Fe2O3 solid solution (0.1–0.3 μm thick), an intermediate (Fe, Co)3O4 layer and an outer Co3O4 spinel layer, respectively. The Co-coated 441 steel sample exhibited better electrical properties. After oxidation at 650 °C for 120 h, the area-specific resistance (ASR) of the Co-coated steel was 3.73 mΩ·cm2, which was 25.4% lower than that of bare 441 steel as 5 mΩ·cm2. Furthermore, the thermal growth process and protection mechanism of Co coating at 650 °C were discussed. [ABSTRACT FROM AUTHOR]

In this study, the effect of cold rolling reduction ratio (CRRR) on the microstructure and mechanical properties of ferritic stainless steel (FSS) 430 were analyzed based on a series of experiments. The results show that the thickness of coarse grain bands decreases with an increase in CRRR, and when the CRRR increases to a certain value, the coarse grain bands break down into refined, equiaxed grains due to the plastic deformation. In addition, the optimization of CRRR was found to benefit both the microstructural refinement and mechanical properties of FSS 430. Also, the optimization of CRRR optimized the texture structure of FSS 430 by reducing the fraction of undesired components ({110} < 110 > component, for example), giving a rise to the plasticity of material. On the other hand, the formation of Lüders band can also be affected by the modification of CRRR. Overall, an optimal CRRR of 70% was obtained with refined microstructure and texture structure, thereby improving the mechanical properties of FSS 430. [ABSTRACT FROM AUTHOR]

Based on the principle of LC resonance, high-frequency sine wave pulse DC TIG welding (HFSWP DC TIG) was developed, and welding experiments were conducted on AISI444 ferritic stainless steel (FSS). The arc characteristics of HFSWP DC TIG and its effect on weld appearance and microstructure were studied theoretically and experimentally. The experimental results show that under the same conditions, compared with constant-current DC conventional arc welding (CAW), the arc pressure and arc thermal efficiency of HFSWP DC TIG are improved, and the weld penetration of the weld is increased by nearly two times. The weld microstructure is single-phase ferrite, and carbonitride, Laves phase, and σ phase are formed in the joint. In addition, according to the theoretical calculation of the pulse current waveform, the reason why the arc pressure of the high-frequency sine wave pulse current is increased compared with the constant-current DC and high-frequency square wave (triangular wave) pulse current is explained. The mechanism of arc shape and weld appearance change is described from the microscopic point of view, and the reason for the appearance of equiaxed grain in the weld is analyzed. HFSWP DC TIG provides a new idea for the improvement of high-frequency pulse technology. [ABSTRACT FROM AUTHOR]

In the present work, a comparison between traditional oil‐in‐water (O/W) based lubricant and nano‐TiO2 additive water‐based lubricants was made to explore the lubrication effects during rolling of ferritic stainless steel (FSS) strips. The results show that marked reduction in rolling force and improvement in the surface quality can be achieved by utilisation of water‐based nanolubricant, which can be attributed to the synergism of rolling effect, mending effect, polishing effect and protection film. An optimal concentration of 3.0 wt% TiO2 nanoparticles is found to exhibit excellent lubrication effects with sufficient nanoparticles at real contact regions without aggregation, leading to 10% reduction in the surface roughness during rolling of FSS strips. [ABSTRACT FROM AUTHOR]

The influence of Cu and Sn on the microstructure, mechanical properties, corrosion resistance, and antibacterial properties of 430L ferritic stainless steel has been investigated by using Thermo-Calc calculations, EPMA (electron probe microanalysis), TEM (transmission electron microscopy), and XPS (X-ray photoelectron spectroscopy). Vichers hardness tests, potentiodynamic polarization, and antibacterial tests were also performed. For a copper content of 1.5 wt.%, the results showed that aging treatments at 600 °C, 700 °C and 800 °C are conducive for the precipitation of an ε-Cu phase in the 430L ferritic stainless steel. It was also found that the ε-Cu phase was composed of almost pure Cu (with a the content of 98.6–99.7 wt.%). Thermo-Calc calculations showed that there was only a very small amount of Fe, Cr, and Mn in the ε-Cu phase. Moreover, the ε-Cu phase was found to substantially coarsen with an extension of the aging time. The size of ε-Cu phase increased from a few nanometers to hundreds of nanometers, and the number of ε-Cu phase decreased gradually. Furthermore, the antibacterial rate of the 2# (430L − 1.5 wt.% Cu) and 3# steel (430L − 1.5% Cu − 0.4 wt.% Sn) samples increased significantly with an extension of the aging treatment time, and the antibacterial rate of the 3# steel was higher than that of the 2# steel sample. The antibacterial rate reached as high as 91.60% and 97.37%, respectively, for an aging time of 79,200 s. [ABSTRACT FROM AUTHOR]

The "gold dust defect" (GDD) appears at the surface of ferritic stainless steels (FSS) and degrades their appearance. Previous research showed that this defect might be related to intergranular corrosion and that the addition of aluminium improves surface quality. However, the nature and origin of this defect are not properly understood yet. In this study, we performed detailed electron backscatter diffraction analyses and advanced monochromated electron energy-loss spectroscopy experiments combined with machine-learning analyses in order to extract a wealth of information on the GDD. Our results show that the GDD leads to strong textural, chemical, and microstructural heterogeneities. In particular, the surface of affected samples presents an α-fibre texture which is characteristic of poorly recrystallised FSS. It is associated with a specific microstructure in which elongated grains are separated from the matrix by cracks. The edges of the cracks are rich in chromium oxides and MnCr2O4 spinel. In addition, the surface of the affected samples presents a heterogeneous passive layer, in contrast with the surface of unaffected samples, which shows a thicker and continuous passive layer. The quality of the passive layer is improved with the addition of aluminium, explaining the better resistance to the GDD. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cost reduction in bipolar plates in proton exchange membrane water electrolyzers has previously been attempted by substituting bulk titanium with austenitic stainless steels protected with highly conductive and corrosion-resistant coatings. However, austenitic steels are more expensive than ferritic steels due to their high nickel content. Herein we report on the corrosion resistance of two high chromium ferritic stainless steels, AISI 442 and AISI 446, as an alternative material to manufacture bipolar plates. Electrochemical corrosion tests have shown that AISI 442 and AISI 446 have similar corrosion resistance, while AISI 446 reveals more noble corrosion potential and performs better during potentiostatic stress tests. The current density obtained during polarization at 2 V versus the standard hydrogen electrode (SHE) is 3.3 mA cm−2, which is more than two times lower than on AISI 442. Additionally, surface morphology characterization demonstrates that in contrast to AISI 442, AISI 446 is not sensitive to intercrystalline or pitting corrosion. Moreover, EDX energy dispersion analysis of AISI 446 reveals no differences in the chemical composition of the surface layer compared to the base material, as a confirmation of its high corrosion resistance. The results of this work open up the perspective of replacing austenitic stainless steels with less expensive ferritic stainless steels for the production of components such as bipolar plates in proton exchange membrane water electrolyzers. [ABSTRACT FROM AUTHOR]

The process of autogenous laser welding of stainless steel X2CrTiNb18 was investigated. The Yb:YAG disk laser was used in the study for welding of 1.5mm thick butt joins. The influence of basic laser welding parameters on the joint quality, fusion zone geometry, microhardness distribution across the butt joint, structure and microstructure of fusion zone (FZ) and heat affected zone (HAZ) was studied and determined. The quality level of the test joints was determined according to the PN-EN ISO 13919-1 standard. The chemical composition of the base metal was determined by spark emission spectroscopy. Results of the study have shown that laser welding parameters have a significant influence on the quality of butt joints. However, it is possible to produce joints that meet the high requirements and criteria of quality. The width of HAZ of the butt joints welded in the investigated range of parameters was narrow and did not exceed 0.2 mm. It was found that the most common imperfections of the analysed joints are concavity of the weld face and insufficient penetration. The HAZ region of joints is characterized by mainly ferritic microstructure with complex carbides precipitates. In turn, the fusion zone is dominated by a ferritic microstructure but also precipitates were observed, which were identified as fine dispersion carbides. Hardness of the base metal is round 160÷170HV0.3. A tendency to increase in hardness in the HAZ and FZ was observed. The maximum hardness measured in HAZ was approx. 220HV0.3, while in the FZ 190HV0.3. [ABSTRACT FROM AUTHOR]

This study investigated the evolution of microstructure and mechanical properties of 25 mm thick S11306 ferritic stainless steel welded joints during Post weld heat treatment (PWHT) by a series of tests, including the optical microscope observation, hardness test, tensile test, bending test, and scanning electron microscope tests. The experimental results show that at as-welded and 870 °C, the toughness of welded joints was poor; and when the heat treatment temperature is between 770 and 820 °C, the content of the composite phase of lower bainite and martensite (LB/M) in the weld zone increased to 43.9~47.6%, and the mean values of tensile strength and yield strength were 476 MPa and 309 MPa, the elongation was close to 40%, and the welded joints show good toughness. The bending test of the welded joints under several groups of PWHT was qualified. Heat preservation of welded joints was conducted at 820 °C for 30 s~1 h and with the increase of holding times, the content of the LB/M in weld zone showed an upward trend, and the recrystallization of base metal zone was basically completed at 15 min. In addition, a recrystallization kinetic model of the base metal zone was also established by measuring the hardness of the base metal zone at 820 °C for different holding times, which provides reference opinions for obtaining the favorable microstructure of steel grades during PWHT in the engineering. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) techniques such as laser powder bed fusion (L-PBF) are rapidly growing due to the inherent design freedom and possibilities to produce components not available with other techniques. This could be utilized in, e.g., the design of new types of heat exchangers in ferritic stainless steels often used for high-temperature applications. Ferritic stainless steels are, however, difficult to weld and could therefore imply obstacles when produced by AM. When establishing the AM-produced alloy in new applications, it is therefore important to increase the understanding of the mechanical properties and high-temperature creep resistance in relation to the unique microstructure and printability. In this study, we have investigated the microstructure of Cr-rich SS446 ferritic stainless steel produced by L-PBF by microscopical and crystallographic techniques. The properties were compared to the conventionally produced tubes. The rapid cooling and reheating during the application of the subsequent powder layers during L-PBF introduces an intriguing microstructure consisting of a ferritic matrix with precipitation of austenite showing a Kurdjumov–Sachs orientation relationship. Characteristic dislocation networks were observed in the L-PBF samples and contributed to the good mechanical properties in the as-built state (more than twice the yield strength of the conventionally produced tube). Furthermore, the creep resistance at 800 °C was superior to the conventionally produced component, suggesting that L-PBF-produced SS446 possesses many advantages regarding production as compared to the conventional route. [ABSTRACT FROM AUTHOR]

A PVD coating is often applied on the surface of metallic alloys to improve their high-temperature resistance. In the present work, a thin titanium layer (1.2 µm) was deposited by PVD on the surface of a stainless steel substrate before high-temperature exposure (800 °C in ambient air). The underlying idea is that metallic Ti converts into Ti oxide (TiO2) during high-temperature aging at 800 °C, thereby slowing down the substrate oxidation. The stability of the coating with and without substrate pre-oxidation was investigated. Morphological, structural, and chemical characterizations were performed and completed by simulation of the film growth and measurement of the mechanical state of the film and the substrate. In the case of the sample that was not pre-oxidized, the oxidation of the steel was slowed down by the TiO2 scale but spallation was observed. On the other hand, when the steel was pre-oxidized, TiO2 provided more significant protection against high-temperature oxidation, and spalling or cracking did not occur. A combination of different kinds of stress could explain the two different behaviors, namely, the mechanical state of the film and the substrate before oxidation, the growing stress, and the thermal stress occurring during cooling down. [ABSTRACT FROM AUTHOR]

Systematic study on the microstructural evolution and mechanical properties of ferritic stainless steel (FSS) 430 with different annealing processes was carried out in the present work. The results show that microstructural refinement can be achieved by optimization of annealing processes, improving elongation, yield strength, and tensile strength of FSS 430. An optimal annealing temperature of 950 ℃ is found with better homogeneity and enhanced mechanical properties among the cold-rolled and annealed FSSs. During annealing processes, the fraction of high-angle grain boundaries of FSS 430 annealed at 950 ℃ is found to be the highest, indicating that a homogeneous microstructure with high recrystallization rate is formed inside the FSS 430 strips. In addition, high fraction of the hard grains (SF < 0.4) and low fraction of the soft grains are found inside FSS 430 annealed at 950 ℃, improving the plasticity of material. Overall, the optimization of annealing processes benefits the microstructural refinement of FSS and thereby improving the mechanical properties of materials. [ABSTRACT FROM AUTHOR]

X2CrNi12 ferritic stainless steel has a wide range of application prospects in the railway transportation, construction, and automobile fields due to its excellent properties. The properties of X2CrNi12 ferritic stainless steel can be further improved by cold-rolling and subsequent annealing treatment. The purpose of this work is to investigate the effect of cold-rolling reduction on the microstructure, texture and corrosion properties of the recrystallized X2CrNi12 ferritic stainless steel by using SEM, TEM, EBSD and electrochemical testing technology. The results show that the crystal orientation characteristics of the cold-rolled sheet could be inherited into the annealed sheet. The higher cold-rolling reduction could promote the deformed grains rotating into the {111} orientation, increasing storage energy and driving force for recrystallization, which could reduce the recrystallized grain size. The orientation densities of α-fiber and γ-fiber were low at 50% cold-rolling reduction. After recrystallization annealing, a large number of grains with random orientation could be produced, and the texture strength was weakened. When the cold-rolling reduction rose to 90%, the γ-fiber texture at {111}<110> was strengthened and the α-fibers, particularly the {112}<110> component, were weakened after recrystallisation annealing, which could improve the formability of the steels. The proportions of special boundaries, i.e., low-angle grain boundaries and low-Σ CSL boundaries, among the grain boundary distribution of the recrystallized X2CrNi12 stainless steel were higher when the reduction was 90%, especially when the annealing temperature was 770 °C. Additionally, the proportion of LAGBs and low-Σ CSL boundaries were 53% and 7.43%, respectively, which improves the corrosion resistance of the matrix, showing the best corrosion resistance. [ABSTRACT FROM AUTHOR]

In contrast to austenitic and martensitic stainless steels, ferritic stainless steels have a lower hardness and wear resistance but exhibit excellent corrosion resistance. Due to this fact, their use in the aerospace, automobile, and house construction industries is restricted. Several methods have been utilized to enhance the tribological characteristics of ferritic stainless steels. In this work, titanium nitride coating has been carried out by using a cathodic cage of titanium material, and later on, the titanium cathodic cage is replaced by an AISI-304 cathodic cage in a CCPN chamber to form iron nitride coating on AISI-430 ferritic stainless steel coupons through a plasma nitriding process for 4 h at a fixed temperature of 400 °C. The microstructures and mechanical traits of all processed and control coupons were analyzed using scanning electron microscopy, X-ray diffraction, ball-on-disc wear tester, and microhardness tester techniques. The results showed that hardness increased up to 1489 HV with the titanium cage, which is much higher than the hardness of the base material (270 HV). The titanium cage-treated coupons have high layer thickness, smooth surface morphology, and a minimum crystallite size of 2.2 nm. The wear rate was reduced up to 50% over the base material after the titanium cage plasma treatment. The base coupon exhibited severe abrasive wear, whereas nitrided coupons exhibited dominant adhesive wear. In the iron nitride coatings, this effect is also important, owing to the more influential cleaning process in a glow discharge, and the better adhesion with enhanced interlayer thickness is attributed to the fact that the compliance of the interlayer minimizes shear stresses at the coating–substrate interface. The use of a graded interface improves adhesion compared with the case where no interlayer is used but a titanium interlayer of comparable thickness provides a significant increase in measured adhesion. For both titanium and iron nitride films, there is a reduction in wear volume which is a function of interlayer thickness; this will have a substantial effect on wear lifetime. Thus by careful control of the interlayer thickness and composition, it should be possible to improve coating performance in tribological applications. [ABSTRACT FROM AUTHOR]

Magnetically impelled arc butt (MIAB) welding is being used in industries for joining metallic tubes and pipes. This research work reported MIAB welding of AISI 409 ferritic stainless steel tubes of 4 mm thickness. Joints were obtained by varying arc rotation current and characterized using various microscopic techniques. An increase in arc rotation current enlarged the joint region and increased the axial shortening. The upsetting was improper at higher and lower limits of the current. The joint consisted of deformed structure which was thermally and mechanically affected (TMAZ). The entire TMAZ was further designated into three regions based on the variation in grain size and the degree of deformation experienced. The grains were extremely refined by upsetting. There was no coarsening of grains to form a heated affected zone (HAZ). There was no phase transformation observed in TMAZ. The average grain size showed an increasing trend as the current value was increased. High density of dislocations was observed in TMAZ which caused significant strengthening of the joint region. TMAZ showed multifold increase in hardness due to grain refinement and dislocation fields. The variation in arc rotation current influenced the joint strength remarkably and shifted the fracture location. The choice of arc rotation current is a key factor to obtain sound joints. [ABSTRACT FROM AUTHOR]

AISI 430 ferritic stainless steel with different initial microstructures was low-temperature plasma nitrided to improve its hardness and wear resistance in the present investigation. The microstructure and properties of the low-temperature nitrided layers on stainless steel with different initial microstructures were studied by an optical microscope, X-ray diffractometer, scanning electron microscope, microhardness tester, pin-on-disk tribometer, and electrochemical workstation. The results show that the low-temperature nitrided layer characteristics of ferritic stainless steel are highly initial-microstructure dependent. For the ferritic stainless steel with a solid solution and annealing treatment, it had the best performance after low-temperature plasma nitriding when compared with the stainless steel with other initial microstructures. The nitrided layer thickness reached 34 μm after nitriding at 450 °C for 8 h. The phase composition of the low-temperature-nitrided layer consisted mainly of a nitrogen "expanded" α phase (αN) and iron nitrides (Fe4N and Fe2–3N). The hardness of the nitrided layer could reach up to 1832 HV0.1. Moreover, the wear and corrosion resistance of the nitrided layer on the solution and annealing treated ferritic stainless steel could be improved at the same time. [ABSTRACT FROM AUTHOR]

Laser surface texturing (LST) is a method to obtain micro-structures on the material's surface for improving tribological performances, wetting tuning, surface treatment, and increasing adhesion. The material selected for LST is AISI 430 ferritic stainless steel, distinguished by the low cost in manufacturing, corrosion resistance, and high strength at elevated temperature. The present study addresses the morphology of new pattern designs (crater array, ellipse, and octagonal shapes). The patterns are applied on the stainless-steel surface by a non-contact method with high quality and precision nanosecond pulsed laser equipment. The investigation of laser parameter influence on thermal affected area and micro-structures is accomplished by morphological and elemental analysis (SEM + EDX). The parameters of the laser micro-patterning have a marked influence on the morphology, creating groove-type sections with different depths and recast material features. From the SEM characterization, the highest level of recast material is observed for concentric octagon LST design. Its application is more recommended for the preparation of the metal surface before hybrid welding. Additionally, the lack of the oxygen element in the case of this design suggests the possible use of the pattern in hybrid joining. [ABSTRACT FROM AUTHOR]

Due to its wide applicability in industry, devising microstructures on the surface of materials can be easily implemented and automated in technological processes. Laser Surface Texturing (LST) is applied to modify the chemical composition, morphology, and roughness of surfaces (wettability), cleaning (remove contaminants), reducing internal stresses of metals (hardening, tempering), surface energy (polymers, metals), increasing the adhesion (hybrid joining, bioengineering) and decreasing the growth of pathogenic bacteria (bioengineering). This paper is a continuation and extension of our previous studies in laser-assisted texturing of surfaces. Three different patterns (crater array-type C, two ellipses at 90° overlapping with its mirror-type B and 3 concentric octagons-type A) were applied with a nanosecond pulsed laser (active medium Nd: Fiber Diode-pumped) on the surface of a ferritic stainless steel (AISI 430). Micro texturing the surface of a material can modify its wettability behavior. A hydrophobic surface (contact angle greater than 90°) was obtained with different variations depending on the parameters. The analysis performed in this research (surface roughness, wettability) is critical for assessing the surface functionality, characteristics and properties of the stainless steel surface after the LST process. The values of the surface roughness and the contact angle are directly proportional to the number of repetitions and inversely proportional to the speed. Recommendations for the use of different texturing pattern designs are also made. [ABSTRACT FROM AUTHOR]

Laser-generated surface patterns provide the means for local mechanical interlocking between the joined materials, tunes the wettability of surfaces that come in contact, and generally are the main factor for bonding strength enhancement, especially between dissimilar materials. This paper presents the influence of different patterning overlays generated with a pulsed laser on the surface of stainless-steel sheets. For all experiments, an overlapping degree of 90% has been chosen between three different patterns, while the engraving speed, pulse frequency and number of passes have varied. The textured surfaces' morphology was assessed through optical microscopy, and the roughness of the surfaces was correlated with the corresponding experimental parameters. The results have indicated promising insights for joining stainless steel to plastic materials, which is otherwise difficult to assess through usual welding techniques. [ABSTRACT FROM AUTHOR]

One of the candidates for metallic interconnects of solid oxide fuel cells is ferritic stainless steel, Crofer 22 APU. Ferritic stainless steel Crofer 22 APU specimens with different surface roughness were prepared by grinding with SiC powder papers of various grits and then thermally cycled in air. Variation in the microstructure of the samples having different roughness with thermal cycling was investigated. Polished Crofer 22 APU specimens after three and five thermal cycles had relatively flat oxide layers with thicknesses of about 13.8 and 17.9 µm, respectively. Micrographs of a trench made by milling with FIB (focused ion beam) for a Crofer 22 APU specimen ground with grit 80 SiC powder paper after 8 thermal cycles (total oxygen exposure time of 200 h at 1073 K), captured by ESB (energy selective back-scattering) and SE2 (type II secondary electrons), showed that the surface of the sample was very coarse and its oxide layer was undulated. In the oxide layer, the phase of the sublayer was Cr2O3, and that of the top layer was (Cr, Mn)3O4 spinel. The surface of the sample ground with grit 80 SiC powder paper was very rough after 60 thermal cycles (total oxygen exposure time of 1500 h at 1073 K). The polished Crofer 22 APU is a better applicant to an interconnect of SOFC than those with rougher surfaces. [ABSTRACT FROM AUTHOR]

The influences of ultrasonic vibration during cold metal transfer welding process on the microstructure, element distribution and pitting resistance of AISI 430 ferritic stainless steel joints with ER 308L as filler metal were investigated. The combined effects of mechanical vibration, acoustic streaming and cavitation of ultrasonic vibration significantly refined the primary ferrite grain in the weld metal and then impacted the subsequent solid-phase transition process, leading to the ~45% reduction of ferrite content in the weld metal. Moreover, these effects also resulted in the homogenization of alloying elements in the weld metal. The pitting corrosion resistance of the welded joints with ultrasonic vibration was increased compared with that of without ultrasonic vibration, but lower than the base metal. The pitting resistance of the weld metal with ultrasonic vibration was higher than that of the weld metal without ultrasonic vibration and base metal, while that of the one without ultrasonic vibration was lower than the base metal. [ABSTRACT FROM AUTHOR]

Ferritic stainless steel has been applied frequently owing to its advantages such as good thermal conductivity, low coefficient of linear expansion, good stress corrosion resistance, and no Ni. However, the welding process will cause the grain size of the weld zone and the heat-affected zone to grow seriously, resulting in a decrease in the toughness of the welded joint. The paper discusses in detail the traditional and improved welding methods of ferritic stainless steel. These improved methods can effectively reduce the grain size or increase the penetration. The process of introducing electric and magnetic pulses can compress the arc, increase the weld penetration, stir the molten pool, refine the grains, and improve the strength and toughness of the weld. The future development direction of ferritic stainless steel welding is discussed at the end of the article. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of grain size reduction, from 120 to 5 μm, on the electrochemical response of Fe-18.5% Cr ferritic stainless steel in 0.01 M NaOH alkaline solution. To analyze the electrochemical characteristics of the material, the potentiodynamic polarization, open circuit potential measurement, cyclic voltammetry, electrochemical impedance spectroscopy, and Mott-Schottky analysis were carried out. Open circuit potential analysis demonstrated that the passive layer developed on a coarse-grained sample is more stable than a fine-grained one. Based on electrochemical impedance spectroscopy measurements, it was concluded that grain refinement reduces the thickness of the passive protective layer and degrades the corrosion resistance of material. Polarization measurements showed that refinement of grain structure reduces the corrosion resistance of the investigated ferritic stainless steel exposed to NaOH solution. The Mott-Schottky analysis demonstrated that the protected layer formed on the surface of the fine-grained sample has donor and acceptor densities (2.43×1021, and 0.4×1021 cm-3, respectively) higher than that formed on the surface of the coarse-grained counterpart (2.29×1021, and 0.36×1021 cm-3, respectively). [ABSTRACT FROM AUTHOR]

Magnetically impelled arc butt (MIAB) welding is the modern version of the ancient forge welding. The abutting edges are preheated by a rotating arc and upset subsequently. This research work is focused on joining 4-mm thick AISI 409 ferritic stainless steel (FSS) tubes using MIAB welding. Three process parameters namely arc rotation current, upset current, and arc rotation time were varied during welding at five levels according to the chosen central composite design (CCD) of experiments. An empirical relationship was developed to predict the effect of process parameters on the joint strength. The macrostructure and microstructure observations were used to comprehend the predicted plots. Weld zone was composed of fine-grained and deformed structure due to the application of heat and pressure and called as thermo mechanically affected zone (TMAZ). Factors such as poorly forged structure, voids, and oxide particles influenced the joint strength adversely. In spite of significant strengthening of the TMAZ, a clearly forged interface was essential to obtain higher joint strength. [ABSTRACT FROM AUTHOR]