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We report field emission (FE) properties of cold cathodes made by a scalable chemical vapor deposition synthesis of three-dimensional graphene (3DG) from a cast catalyst followed by cold rolling. This process leads to an increase in mechanical strength and electrical conductivity of the tested material. For a given distance between the tip of the cathode and the anode, it is found that the FE current from the edge of a single sheet of cold-rolled 3DG-based cathode can be increased by over one order of magnitude when rolling the 3DG sheet in the shape of a cylinder with several turns. A FE current in the order of 4.5 mA was measured from a 3 mm diameter cold-rolled 3DG cylinder with six turns at a bias of 2400 V for a separation of 0.5 mm between the tip of the cylindrical cathode and the anode. The FE data of all cold-rolled 3DG-based cathodes are well fitted by the expression proposed by Abbot, Henderson, Forbes, and Popov [Filippov et al., R. Soc. Open Sci. 9, 220748 (2022)], I m = C V m κ exp (− B / V m) , where I m is the FE current, V m is the bias applied between the cathode and anode, and B and C are fitting parameters. It is found that κ = 1 and 3 / 2 for FE from the surface and edge of the cold-rolled based cathodes, respectively. [ABSTRACT FROM AUTHOR]

Natural-gas pipelines converted to carry hydrogen could have reduced mechanical properties due to hydrogen embrittlement. The tensile properties of the X65 D pipeline steel from the Dampier-Bunbury Natural Gas Pipeline were assessed in air and in hydrogen. The microstructure consisted of ferrite and pearlite elongated in the transverse and longitudinal directions by the hot and cold rolling during pipe production. Tensile tests were conducted using the linearly increasing stress test with cathodic hydrogen charging. Specimens were from the base metal, weld metal and heat-affected zone, from varying depths in the pipeline wall and for longitudinal and transverse orientations. There was no influence of hydrogen on steel strength, and no sub-critical crack growth. Hydrogen produced a similar reduction in the ductility for the base metal, weld metal, heat-affected zone, and at different depths in the pipe wall. The ductility reduction in the transverse direction was greater than in the longitudinal direction which correlated with more brittle quasi-cleavage facets, and which was attributed to the more pronounced pearlite banding in the transverse direction. The reduction of ductility by hydrogen was attributed to hydrogen causing a change in fracture mode from ductile micro-void coalescence in air to the altered micro-void coalescence fracture mechanism in hydrogen and to the introduction of quasi-cleavage in the presence of hydrogen which might have been by the HELP + HEDE mechanism. • Hydrogen charging reduced ductility similarly for the weld and base metal of X65. • Hydrogen embrittlement was more severe in transverse direction than longitudinal. • SEM showed hydrogen introduced surface cracks from which fracture propagated. • Reduction in ductility due to hydrogen was attributed to HELP + HEDE. • Hydrogen charging had no effect on strength. [ABSTRACT FROM AUTHOR]

Ensuring product quality requires the accurate detection of strip flatness during cold rolling. For cold rolling mills with intermediate roll shifting control, the uneven stiffness induced by the shifting process can cause the strip to tilt in the mill, which can affect the accuracy of strip flatness detection. In this study, the strip tilt is defined, and a finite element model of the S6-high mill is constructed using ABAQUS software to study the strip's deflection and flattening behaviour during the rolling process and the effect of different rolling process parameters on the strip tilt. The specific spatial position of the rolls during the rolling process is also examined, and the main structure of the mill is identified as the primary cause of strip tilt. This research provides a theoretical basis for the strip's absolute position change in the rolling process, which can enhance the measurement accuracy of flatness detection roll in the future. [ABSTRACT FROM AUTHOR]

Three Al–Zn–Mg–(Mn) alloys with 0, 0.6, and 1.0 wt pct Mn were thermomechanically processed from cast billets to wrought aluminum sheet using hot extrusion and cold rolling. Small-angle neutron scattering (SANS) experiments, performed in conjunction with electron microscopy characterization, allowed detailed microstructural characterization on sample sizes orders of magnitude larger than possible with microscopy alone. Accordingly, robust assessment of microstructural changes after the different stages of thermomechanical processing were possible for two distinct populations of precipitates and dispersoids differing in size by a factor of ~ 20. Size distributions and volume distributions of sub-micron Al6Mn and nano-sized Mg–Zn η′ precipitate phases were obtained from SANS data and compared with those estimated from Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The SANS derived η′ size distributions and volume fractions were found to be similar for the alloys, suggesting that the prior precipitated Al6Mn dispersoids did not interfere with the precipitation of the η′ phase. The TEM derived size and volume distributions for the η′ phase were found to be in good agreement with those derived from SANS. The agreement between SANS and SEM derived size and volume distributions for the Al6Mn dispersoids was less robust. The anisotropy in the SANS data allowed confirmation of a preferred orientation of Al6Mn dispersoids with extrusion/rolling direction, noted in microscopy observations, on the much larger spatial extent typical of SANS. [ABSTRACT FROM AUTHOR]

The use of cold ring rolling as a typical forming method for bearing steel has shown considerable effects on the development of microstructures in subsequent heat treatment. However, the impact of prior cold rolling on the bainite formation remains unclear. In this study, the influencing mechanism of prior cold rolling on the bainite transformation kinetics for aviation M50 bearing steel has been investigated. It was observed that cold rolling shortened the incubation period of bainite and limited the width of the bainite sheaves. The bainite transformation process was first promoted and then inhibited by cold ring rolling. To investigate the decisive factors affecting the bainite transformation kinetics under cold rolling, in-situ X-ray diffraction analysis and microstructure characterization were conducted. The results showed that although there was a recovery effect during austenitization, the dislocations introduced by cold rolling were partially retained and the carbide dissolution is enhanced. The dislocation density, carbon content, and compressive strength of the high-temperature austenite were increased, and the austenite size was refined, thereby directly affecting the bainite transformation process under cold rolling. Accordingly, a kinetic model for bainite transformation considering cold rolling was established, which revealed the promotion effect of increasing grain boundaries and low-angle grain boundaries on bainite nucleation in the early stage and the inhibition effect of high-density dislocations and high carbon concentration on bainite sheaves growth in the late stage of austempering under cold rolling. [ABSTRACT FROM AUTHOR]

Symmetric and asymmetric cold rolling of steel strips was carried out. There were 5 passes at 1700 mill to obtain 0.5 mm strip thickness from 2 mm initial strip thickness. The asymmetric rolling technique—with different roll radii and equal circumferential speeds of rolls—was applied on an industrial mill for the first time: rolls have different diameters and equal circumferential speeds. The research on the microstructure and mechanical properties was carried out after each of the rolling types. It was established that steel's strength is 11–13% higher after asymmetric rolling compared to symmetric one. High shear strains were revealed after asymmetric rolling. Computer simulation of experimental rolling was done using DEFORM finite element method (FEM) software in two-dimensional mode. The stress state of the strips was examined as a result of computer simulation. The computer simulation results showed that the absolute maximum shear stress at the exit of the deformation zone value is 1.6 times higher at asymmetric rolling than at symmetric one. [ABSTRACT FROM AUTHOR]

Workers' health is jeopardized in steel rolling workshops due to the production of particulate matter. These particles' physicochemical properties have a direct impact on their effects on human health, emphasizing the importance of understanding these properties for exposure control. This study investigated particulate matter emissions in hot and cold steel rolling workshops, focusing on mass concentrations, particle size distributions, and elemental compositions. The findings revealed that particles predominantly range from 0.3 to 1.0 μm in size, with irregular block-like and fibrous morphologies. Elemental analysis showed distinct compositions: the main components in the hot rolling workshop were oxygen, calcium, silicon, carbon, and iron while those in the cold rolling workshop were oxygen, silicon, aluminum, carbon, and iron. The particulate matter concentrations were higher in the hot rolling workshop than in the cold rolling workshop. The Rosin–Rammler particle size distribution function was applied to characterize particle size distribution at emission sources. This paper highlights the dynamic variations and spatial distribution patterns of particulate matter during rolling processes, providing key data for understanding particulate matter behavior in industrial environments and informing targeted pollution control strategies. [ABSTRACT FROM AUTHOR]

High-performance lightweight materials are urgently needed because of energy savings and emission reduction. Here, we design a new steel with a low density of 6.41 g/cm3, which is a 20% weight reduction compared to the conventional steel. The mechanical properties and microstructures of the steels prepared with different routes are systematically explored by utilizing uniaxial tensile testing and transmission electron microscopy. The steel processed by cold rolling and recrystallization annealing at 950 °C for 15 min shows an ultra-high yield strength of 1241 ± 10 MPa, while retaining a good ductility of 38 ± 1%. The high yield strength is mainly related to the synergistic precipitation strengthening introduced by nanoscale B2 and κ′-carbides. It is encouraging to notice that the yield strength increased without scarifying ductility, compared to the ST steel. The key reason is that the high strain hardening rate is activated by combined factors, including the blockage of numerous twins and nanoscale B2 to the dislocation movements, and dynamic slip band refinement. This study is instructive for concurrently enhancing the strength and ductility of austenitic lightweight steels with fully recrystallized grains and dual nano-precipitates. [ABSTRACT FROM AUTHOR]

Copper matrix composites (Cu-MCs) have garnered significant attention due to their exceptional electrical, wear-resistant, and mechanical properties. Among them, Al2O3/Cu composites, reinforced with Al2O3, are a focal point in the field of high-strength, high-conductivity copper alloys, owing to their high strength, excellent electrical conductivity, and superior resistance to high-temperature softening. Cold deformation is an effective method for enhancing the mechanical properties of Al2O3/Cu composites. However, during cold deformation of large-cross-sectional Al2O3/Cu composites, the inhomogeneity in microstructure and properties induced by varying stress states cannot be overlooked. In this study, cold deformation of 1.12 wt% Al2O3/Cu large-cross-sectional composites was performed using a rolling process, coupled with finite element numerical simulations, to investigate the distribution characteristics of microstructure and properties during the rolling process. The results indicate that under cold deformation, the hardness of the material increases linearly from the surface layer to the core, while the change in electrical conductivity is minimal. The increase in hardness is closely related to variations in dislocation density and grain size, with dislocation density being the dominant strengthening mechanism. Quantitative analysis reveals that strain inhomogeneity during cold deformation is the primary cause of microstructural differences, leading to variations in mechanical properties at different positions. This study provides a theoretical basis for understanding the inhomogeneity of cold deformation in large-sized Al2O3/Cu composites and for controlling their microstructure–property relationships. [ABSTRACT FROM AUTHOR]

Through the ferrite single-phase parameters of M50 bearing steel obtained based on nanoindentation experiments and the representative volume element (RVE) model established based on the real microstructure of M50, this paper established a multiscale finite element model for the cold ring rolling of M50 and verified its accuracy. The macroscale and mesoscale flow behaviors of the ring during the cold rolling deformation process were examined and explained. The macroscopic flow behavior demonstrated that the stress distribution was uniform following rolling. The equivalent plastic strain (PEEQ) grew stepwise over time, with the raceway showing the highest PEEQ. The mesoscopic simulation revealed that the stress was concentrated in the cementite, and the maximum occurred at the junction of the ferrite and cementite. The largest PEEQ was found in the ferrite matrix positioned between the two adjacent cementites. The cementite flew with the deformation of the ferrite. The radial displacement of the cementite decreased from the edge of the raceway to both ends and decreased from the inner to the outer surface. Its axial displacement was basically the same on the inner surface and decreased from the inner to the outer surface. Its circumferential displacement decreased from the inner and outer surfaces to the intermediate thickness region. [ABSTRACT FROM AUTHOR]

The clogging of the submerged entry nozzle (SEN), as an important device to connect the tundish and the mold, has been widely concerned. However, until now, the clogging of the SEN cannot be eliminated during the casting. Herein, the clogging behavior of the SEN during the casting of ultralow‐carbon steel is studied using an external DC electric field. The findings demonstrate that the DC electric field inhibits the growth of the clogging on the outlet and the thickness of the clogging layer is small, which ensures the integrity of the profile of the outlet. After DC treatment, the interface of the clogging is clear and the density is increased, which reduces the pollution to molten steel. At the same time, the fluctuation of the mold level is significantly improved, and the defect rate of cold rolling is effectively reduced to 30% of the original level, which is beneficial to the overall performance of the slab. [ABSTRACT FROM AUTHOR]

The microstructural and textural evolution, as well as the recrystallization kinetics under different cold‐rolling methods and their influencing mechanism on the properties of the thin‐gauge 3.5%Si nonoriented silicon steel, are investigated by electron backscattering diffraction, X‐ray diffractometer, tensile, and magnetic properties test. The results indicate that compared with the primary cold‐rolling process, the reduction rate of secondary cold‐rolling process is lower (58.3%), and many shear bands are formed in the coarse cold‐rolled sheet, which leads to the formation of strong Goss and cube texture after recrystallization annealing. Owing to the high annealing temperature, the average grain size of finished annealed sheet is little different under different cold‐rolling processes, so the mechanical properties and high‐frequency iron loss are basically the same. The iron loss of the secondary cold‐rolled products decreases with an increase in frequency, and the improvement in the iron loss of the high field (1.5 T) becomes larger than that of the low field (1.0 T). Given the high anisotropy index of the Goss texture, the iron loss anisotropy of the secondary cold‐rolled sheet is higher. Considering the magnetic and mechanical properties, the optimum process is the secondary cold rolling with the intermediate annealing temperature of 900 °C. [ABSTRACT FROM AUTHOR]

The surface hardness uniformity of Cr12MoV steel, used as cold-rolling work rolls, is crucial. However, during the laser cladding process of M2 high-speed steel powder, improving the surface hardness uniformity of the cladding layer by adjusting the laser process parameters alone is very limited. Substrate preheating is mostly used to mitigate the high stress and cracking defects in the cladding layer, while its effect on improving the surface hardness uniformity of the cladding layer has been neglected. In this paper, the influence mechanism of substrate preheating on the surface hardness uniformity of the cladding layer is investigated by combining experimental and numerical simulation methods. The results show that as the substrate preheating temperature increases (from 20 to 400 °C), the temperature and residual stress differences between the front and rear halves of the cladding layer progressively decrease. The microstructure of the cladding layer transitions from a mixed distribution of columnar and equiaxed dendrites to a uniform equiaxed dendritic structure. Furthermore, the distribution trend of Cr elements between the both halves becomes more homogeneous, and the surface hardness fluctuation coefficient of the cladding layer decreases from 75.2 to 9.1. Substrate preheating can improve surface hardness uniformity by promoting microstructural uniformity through improved temperature distribution and chemical composition homogeneity during molten pool solidification. This finding facilitates the development of high-quality M2 laser cladding layers with uniform surface hardness on Cr12MoV steel and may also provide valuable insights for the development of other cladding layers. [ABSTRACT FROM AUTHOR]

An accurate and numerically efficient description of the rolling process is a challenging task since the degree of computational accuracy is directly related to the complexity of the algorithm employed. In the most general case, finite element models (FEM) are used for the simulation of deformation processes; however, these techniques require significant computational time. Analytical approaches, which are suited for one or another deformation process, seem to be a proper alternative to FEM. In this study, the well-established flowline modeling approach (FLM) is extended with the aim of better describing the flow of a rolled material in both surface and subsurface regions. A new flowline function is defined, while the velocity along the particular streamline and strain rate gradients are determined analytically, based on the roll gap geometry. The new model is validated by comparing the velocity components to the ones computed by the finite element model. The distortion of meshes predicted by both FEM and FLM follow the same evolutionary pattern. [ABSTRACT FROM AUTHOR]

Herein, large electrical conductivity of 21% IACS and high strength of 1118 MPa in the Cu‐3.3 wt%Ti alloy are successfully achieved based on the coupling control of microalloying, deformation, and aging. It is revealed that compared with the Mg‐free Cu‐3.3 wt%Ti alloy prepared by traditional treatment methods, such as aging, deformation + aging, and the novel method of preaging + cold rolling + aging, both the addition of 0.1 wt%Mg and the novel method of preaging + cold rolling + aging not only can greatly improve the uniform distribution level of dislocation formed during cold rolling and reduce the average size of precipitates, but also can significantly improve the formation of multiscale precipitates with higher volume fraction and their coupling distribution with dislocations, which effectively improve the electrical conductivity and strengthening contribution of precipitates and dislocation simultaneously. The results shed light on the understanding of related mechanisms in Cu‐Ti alloys and hopefully also provide theoretical guidance for industrial production and applications of Cu‐Ti alloys with excellent properties. [ABSTRACT FROM AUTHOR]

Through a series of thermal–mechanical processing (TMP) routes with various ratios of cold rolling (CR) and subsequent high-temperature annealing, Inconel625 alloy samples with different strain states were prepared to investigate the evolution of grain boundary characteristic distribution (GBCD) in the process of grain boundary engineering (GBE). The effects of the TMP parameters on the microstructure of GBE were studied by electron backscattering (EBSD), and the effects of different TMP parameters on the microstructure and hardness of GBE were analyzed. The results show that different restraints have different mechanisms of grain boundary network formation, and that strain is the main mechanism of boundary migration. When the deformation is 5%, the proportion of low ΣCSL grain boundary is relatively large at each annealing temperature, and the proportion of low ΣCSL grain boundary reaches the maximum at 1075°C. With the increase of temperature and deformation, the dominant mechanism of grain boundary fracture gradually changes from the new twin mechanism to the ∑3 regeneration mechanism. The large initial grain size can delay the nucleation of strain-free grains during TMP treatment. Finally, the grain boundary evolution of the sample in each stage of GBE production and the change of hardness of the sample after GBE are described. [ABSTRACT FROM AUTHOR]

Cold forging of carburizing steels has been utilized as a viable alternative to hot forging, but often increases the susceptibility to abnormal growth of prior austenite grains in localized areas associated with strain gradients induced during forging. The effects of microalloying with (Al + N) and (Nb + Mo) and strain (controlled here by reduction ratios during cold rolling) on abnormal grain growth (AGG) were investigated in medium-carbon low-alloyed modified AISI 4121 steels, heat treated to a final microstructure of martensite after simulated carburization at 1203 K. After cold deformation followed by the carburizing simulation, abnormally grown prior austenite grains were found in both (Al + N)-alloyed 'AN' and (Nb + Mo)-alloyed 'NM' steels. The number density of abnormally grown grains increased rapidly from a reduction ratio of 0 to 10 pct (true strain of 0.11) and then decreased to zero at a reduction ratio of 50 pct (true strain of 0.69). In the NM steel, the maximum prior austenite grain size and number density of abnormally large grains at a reduction ratio of 10 pct were larger than those of the AN steel, indicating a higher susceptibility to AGG in the NM steel. Complex (Nb,Mo)(C,N) carbonitrides present in the NM steel coarsened with time during long-time (328 minutes) high-temperature (1203 K) carburizing simulations. These results demonstrate that understanding AGG through microalloying and the amount of cold working play a crucial role in the wide application of cold-forging carburizing steels. [ABSTRACT FROM AUTHOR]

The objective of this manuscript is to present an analytical-numerical methodology for predicting residual stresses after cold rolling of steel sheets, with or without coiling/uncoiling steps. This proposal considers the contribution of hardening after each pass, the increase in temperature arising from forming, with the consequent appearance of a thermal gradient between the center of the sheet and its surface, and the eventual plastic deformation/relief after coiling/uncoiling. Predicted results were compared to experimental data collected from a steel plant, as well as to results available in the literature. The coincidence of values was quite satisfactory, especially in the central third of the residual stress distribution curves. Experimental results from more diverse processes, with greater variation in the number of passes and strain rates, are desirable for definitive validation of the proposed prediction model. [ABSTRACT FROM AUTHOR]

The third‐octave mode mill chatter is a prominent rejection in the efficiency and quality of the strip. The third‐octave mode chatter frequency is in the range of 150–250 Hz. Frequency analysis of vibration acceleration signal or original rolling process parameters is an effective method to detect third‐octave mode chatter characteristics, and cold rolling mill chatter identification by frequency analysis is quite desired. However, original industrial data are contaminated by noise, making it difficult to obtain the principal component of 150–250 Hz when chatter occurs. Besides, it is necessary to find out the root rolling condition parameter causing chatter. To meet the early warning of the third‐octave mode chatter in the production line, a new adaptive cuckoo search algorithm variational mode decomposition (CSA‐VMD) and transfer entropy–based root cause diagnosis models are proposed. The verification results showed that the CSA‐VMD method can extract the third‐octave mode chatter component and avoid the mode mixing problem and endpoint effect. Early mill chatter warning should be provided when the tension fluctuation exceeds 20% in the uniform speed rolling phase. [ABSTRACT FROM AUTHOR]

Thin-walled tubes have been extensively used as energy absorbers in many engineering structures that are under dynamic or quasi-static loads. In this article, the effect of corrugation and its geometry on the collapse characteristics of aluminum concertina tubes under quasi-static axial load is investigated both experimentally and numerically. The numerical simulations were performed with the use of LS-Dyna commercial software. Then, several chosen samples were tested experimentally to verify the results of the simulation. Forty different samples with four different corrugation geometries including singly isosceles triangular corrugation, continual isosceles triangular corrugation, continual scalene triangular corrugation, and continual semi-circular corrugation, and each with 10 different size dimensions were simulated. Among all of these simulations, six of them, each with two replicates were subjected to experimental tests. Experimental examples are aluminum cylindrical thin-walled tubes with the same thickness, height, and diameter that corrugations with different geometries are applied to them by the use of the cold rolling method. Finally, to describe the findings in more theoretical terms, a comparison between our obtained results and earlier theoretical investigations is made. The results show a significant influence of corrugations application on the improvement of the collapse characteristics of the cylindrical tubes so that the collapse style of intact tubes can be controlled by applying corrugations. The results show that by increasing the amplitude and number of corrugations, the absorbed energy, and the initial maximum force decrease. It is also found that among the different corrugation geometries, the corrugations with singly isosceles triangular geometry have the highest energy absorption as well as the lowest initial maximum force. [ABSTRACT FROM AUTHOR]

We study a multi-product production and inventory planning problem with uncertain demand in the cold rolling stage of steel production processes. The problem is to determine the production amount of each product in each planning period so that the sum of production, inventory holding, and backorder costs is minimized. We first formulate it into a Markov decision process (MDP) model, considering dynamic demand. Aiming at the proposed large-scale MDP model, we develop the improved Approximated Dynamic Programming (ADP) algorithms, which are composed of the reformulation and the approximation functions for the value function in MDP. Linear and two quadratic approximate functions are proposed to approximate the value function. Numerical experiments show the optimal gaps of the different approximation methods and illustrate the efficiency of the proposed ADP methods. [ABSTRACT FROM AUTHOR]

This study focuses on the effect of pre-deformation on hydrogen diffusion and hydrogen embrittlement of the high alloy austenitic TRIP steel X3CrMnNiMo17-8-4. Different cold-rolled steel sheets with thicknesses of ≤400 µm were electrochemically charged on both sides in 0.1 M sodium hydroxide with hydrogen for two weeks. Comparative measurements on uncharged and immersed samples prove that hydrogen causes embrittlement in this steel for all investigated states. The embrittlement increases with increasing pre-deformation and is accompanied by deformation-induced martensite formation. The corresponding fractured surfaces were examined using electron microscopy and compared to modelled hydrogen distributions with previously determined diffusion coefficients. For this purpose, various diffusion coefficients are determined using the Devanathan–Stachurski permeation test and hot extraction in order to describe the diffusion process. The hydrogen concentration profiles and the fractographic analyses show a good agreement, so this study provides a basis for estimating the embrittlement behaviour for later application. [ABSTRACT FROM AUTHOR]

This study investigates the differences between deformation-induced martensite (DIM) and thermal-induced martensite (TIM) in 304 austenitic stainless steel, focusing on their formation, distribution, and behavior during annealing. DIM was generated through cold rolling (CR), while TIM was produced via cryogenic treatment (CT). Microstructural characterization revealed that both martensite's are distributed in blocky forms, with DIM exhibiting a finer grain structure compared to TIM. During the annealing process, both types of martensite undergo reverse transformations back to austenite, but DIM begins to reverse earlier at a slower rate. Consequently, after annealing, DIM yields a higher amount of reversed austenite (RA) with smaller grain size, whereas TIM transforms into fewer but larger RA grains. This study provides critical insights into the distinct phase transformation mechanisms of DIM and TIM, offering a deeper understanding of their effects on the microstructure and mechanical properties of 304 austenitic stainless steel. This knowledge is valuable for optimizing processing techniques and enhancing material performance in industrial applications. [ABSTRACT FROM AUTHOR]

In this study, the effects of plastic deformation induced by cold-rolling on the evolution of the microstructure and the resultant corrosion resistance of 316L stainless steel in PEMFCs cathode environment are investigated. The results show that cold deformation changes grain size, grain boundary angle, low-∑ coincidence site lattice (CSL) grain boundaries and phases of the alloy. The best corrosion resistance is achieved in 316L stainless steel with 50% cold rolling deformation, mainly because the increase of low-∑ CSL grain boundaries and O2−/OH− ratio. The uniformity and compactness of the passive film also have a beneficial effect on corrosion resistance. When the cold-rolling deformation is 70 %, the dissolution of martensite accelerates the corrosion rate thus leading to poor corrosion resistance. • Grain boundary angle, low-∑ coincidence site lattice (CSL) grain boundaries and phases change by cold deformation. • Best corrosion resistance is achieved with 50% cold rolling deformation. • Dissolution of martensite by 70% cold rolling deformation accelerates corrosion rate and leads to poor corrosion resistance. [ABSTRACT FROM AUTHOR]

Cold rolling chatter is one of the bottlenecks to improve the production quality and efficiency of high-strength thin strip, so it is very important to predict and identify the chatter states. The accumulation of industrial data from the rolling process and the development of machine learning technology have opened up a path to solve this problem. However, due to low density and uneven distribution of actual process data, knowledge learning and states identification of cold rolling chatter phenomena are confined. Therefore, based on the combination of actual production data and simulation data, a novel identification method is proposed and applied to identify the cold rolling chatter states. Firstly, the actual vibration signals are collected and the simulation data generated from chatter model are used to supplement data in chatter states. The sample space is constructed based on the semi-supervised transfer component analysis (SSTCA) to realize the fusion of actual production data and simulation data. Then, different cold rolling states are identified by particle swarm optimization-support vector machine (PSO-SVM) and back propagation neural network (BPNN), respectively. Finally, the identification results of PSO-SVM and BPNN are combined based on the Dempster-Shafer (D-S) theory. It can be drawn that SSTCA can effectively solve the problems of low density and uneven distribution of industrial data by fusion of multi-source data, and D-S theory can realize the connection of different machine learning methods. Furthermore, the presented method can more accurately identify different chatter states in the rolling process. [ABSTRACT FROM AUTHOR]

Cu alloys are extensively utilized in electronics for heat exchangers, electrical conductors, automotive connectors, and electrical contacts. To meet the demands of miniaturization, these alloys must exhibit enhanced strength and electrical conductivity. We investigated the microstructural and precipitation properties of the Cu–Ni–Si–Co alloy at the solution treatment temperature (1,050°C). We subjected the alloy to cold rolling and ageing. The secondary-phase particles dissolved completely at higher temperatures, increasing the concentrations of the Ni, Si, and Co solutes within the Cu matrix. This enhanced supersaturation facilitated higher precipitation during ageing, resulting in fine (Ni,Co)2Si precipitates with a number density of 12.3 × 1010 cm−2. The alloy was strengthened by the Orowan mechanism and exhibited good electrical conductivity. Moreover, nanoscale (Ni,Co)2Si precipitates were formed. We achieved the highest hardness of 251 hV and an electrical conductivity (EC) of 51% International Annealed Copper Standard (IACS). [ABSTRACT FROM AUTHOR]

Elastic modulus is the core of mechanical spectroscopy to study the actuation-based performance, lifetime, reliability, and stability of pure metals as well as alloys. In this investigation, a prototype system has been discussed for measuring the elastic properties of pure metals such as Cu (99.99%), Al (99.99%), and Ni (99.99%) using electrostatic force. The samples were processed by cold rolling producing specimens of 10–100 microns thickness. A variable potential difference ranging from 1 to 370 V DC was supplied, thus applying a variable electrostatic force to the specimen. The whole system is concentrated on the measurement of micro- to macroscale levels, and a powerful optical microscope evaluates the deflection. The current system has been used to estimate the samples' elastic moduli and then compare it with those obtained by the well-known tensile stress–strain testing method. Finally, the experimental principle of measuring elastic modulus was developed to conduct further research on the metallic materials that are induced by external stimuli like magnetic fields, lasers, and/or heat. [ABSTRACT FROM AUTHOR]

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Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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 Hebei Metallurgy is the property of Hebei Metallurgy 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.)

With the development of rolled steel strips towards higher strength and thinner thickness, negative forward slip has been frequently observed during the process of cold rolling, and this phenomenon closely related to interface is believed to seriously influence rolling stability. However, the existing classic forward slip models are limited to calculating positive forward slip values and cannot reflect negative forward slip effects. Therefore, in this paper, based on BLAND-FORD forward slip theory, a novel modified forward slip model capable of predicting negative forward slip is established and verified, in which the corresponding flattened curve is characterized and a compensation coefficient related to actual tension and coil number is supplemented. Then, a dimensionless sensitivity factor is defined to compare and analyze the influences of various parameters on forward slip through the modified model, in order to pick a more effective and reasonable regulation approach. Finally, an idea of keeping stable forward slip through dynamic tension regulation is suggested and applied in the actual rolling process, and it is drawn that this strategy can be used to avoid fluctuations of process parameters and suppress mill chatter. As a result, the presented modified forward slip model can identify both positive and negative forward slips and is helpful in regulating the interface state and improving the stability of the rolling process. [ABSTRACT FROM AUTHOR]