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Low boron steels are the only class of steel capable of forming a fully martensitic microstructure after hot stamping when a cooled tool is used, and the maximum stress can reach 1500 MPa. The purpose of this work is to study the applicability of 22MnB5 sheet metal as protective masks in hot forging dies. Sheets that were 1.3 mm thick were cut in samples of 110 mm diameter and heat treated in conditions similar to direct hot stamping and placed on the hot forging die. Cycles of 25, 50, 75, and 100 forgings were performed, and at each cycle, the metallic mask was replaced for characterization. Microhardness profiles, micrographic analysis by optical and electron microscopy, and profilometry profiles were used to determine the occurrence of surface wear on the masks after each forging cycle. The main types of superficial wear were abrasive and plastic deformation. However, the masks showed high resistance to wear and did not present failures that would make them unusable until the studied condition of a cycle of 100 forgings.

Large parts such as shafts for wind turbines are hot forged by upset and drawing. The repetitive heating, deformation, and cooling cause different metallurgical phenomena which directly influence the material behavior during and after the forming process. Particularly, while forging these large size parts, the temperature distribution does not remain uniform. This warrants a systematic study on heating and forging workpieces at variable temperature and austenitizing times. In this work, the influence of austenitizing time and temperatures on the microstructural evolution of the 42CrMo4 steel has been investigated. Samples have been austenitized and maintained at temperatures of 900°, 1000°, 1100°, and 1200 °C for 22, 66, and 200 min each and subsequently forged and quenched. The results have shown 42CrMo4 presented a complete recrystallized microstructure only when austenitized at 1200 °C for 200 min. Microhardness profiles have shown that increasing austenitizing time combined with higher temperature decreases the microhardness values in agreement with the decrease in resulting force; thereby, the related metallurgical phenomena of recovery and recrystallization cause material softening.

The absorber plates in solar energy collectors are usually manufactured using copper pipes welded or pressed to aluminum sheets. This paper presents the development of an innovative model of absorber plate for flat plate solar collector using the incremental sheet forming (ISF) and the friction stir welding (FSW) processes. This absorber plate is formed and welded symmetrically using two 1 mm thick AA1200-H14 aluminum sheets, as to allow water ducts to be formed between them. In order to determine the ISF parameters, six groove test experiments were conducted varying tool diameter and step-down value. The results of the groove test were compared with those obtained by finite element simulation. To determine the FSW parameters, four experiments were conducted varying the feed rate. Following that, a flat plate solar collector absorber plate prototype was manufactured. Based on the results, it is believed that the proposed approach seems to be effective to manufacture solar collector absorber plate prototypes using the ISF and FSW processes. The ducts were manufactured by ISF until the final thickness determined in the project (0.48 mm) without sheet cracking. It was also possible to carry out the FSW process of joints without defects identified in the bending test, however, some improvements are necessary to guarantee the tightness of the joint.

Wear is the main mechanism that reduces the lifetime of forging dies used in closed die forging. A newly proposed approach to decrease die wear is the concept of protective sheet metal forging die covers, where an inexpensive and easy-to-exchange sheet metal die cover is used to protect forging dies. After this concept has been fundamentally validated by previous studies, the presented work aims to further evaluate the protective effects of this concept regarding wear reduction. First, an application-oriented experiment of the die cover concept on forging dies for producing square flange was conducted. On both the forging dies with and without die covers 100 forging strokes were carried out. The wear depths of both forging dies were then measured and compared. The results indicated that the forging die with die covers has up to 98% less wear than the forging die without die covers. The expected tool life of the forging die with die covers is therefore 600% longer. In addition, the die cover applied in the experiment achieved the service life of 100 forging cycles without being distorted, which reached the maximum service life of the die cover concept so far.

This paper aims to evaluate the morphological evolution of a magnesium-aluminum alloy (Mg-6Al-3La-1Ca) processed by a mechanical stirring process (MSP) with different stirring times. An apparatus for semisolid metal alloy processing was used to melt and obtain rheocast material. Transformation temperatures were determined at a slow cooling rate using computer-aided cooling curve thermal analysis (CA-CCTA) and differential scanning calorimetry (DSC). Isothermal mechanical stirring (605 °C), at 950 rpm, was carried out with a solid fraction of 0.29 and stirring times of 0, 1, 2, 4, 8 and 10 min, followed by fast cooling in water. The results showed that the microstructure after conventional casting (0 min—no stirring) is composed of an α-Mg dendritic matrix, Al11La3, (Al,Mg)2Ca and Mg2Ca compounds. With the 1-min stirring time, it was not possible to obtain globular structures. For stirring times longer than 2 min, a primary α-Mg globular morphology was obtained. Microstructures with 2 min of stirring time showed better globularization than those obtained under the other conditions. Morphological changes were observed for Al11La3 and (Al,Mg)2Ca after the MSP followed by fast cooling.

Cold extrusion is known as a metal forming process and used due to its dimensional precision. However, the process definition is obtained by empirical methods where experiments are performed previously and based on a “trial and error” method. To reduce costs, companies have been looking for the support of numerical simulation softwares with metal forming application. This study describes the investigation of the effect of different levels for prestressing of cold extrusion gear tool by using the software Simufact Forming. The dimensional deviations of the gear tooth were obtained from two numerical simulations and compared. The application of shrink rings for the prestressing of tooling was evaluated using two different methods to compare their efficiency. The first one is using conventional shrink rings with tool steel, while the second is the stripwinding concept developed by the company STRECON. To produce spur gears, the low carbon steel SAE 10B22 was used.

Incremental Sheet Forming (ISF) and particularly its Single Point (SPIF) variant has been studied intensively over the last years given the potential for low-cost prototyping and small batches production. Numerical and experimental works have been covering a widespan of materials and geometries. This paper fills an important gap regarding studies of the SPIF process applied to brass alloys, and particularly the commonly used Cu-35Zn brass alloy. Despite being a material widely used in industry for centuries, with excellent cold formability and innumerous applications, there is still no relevant information on the mechanical response and properties of this material under SPIF. This research is based in SPIF experiments with brass alloy sheets with different thicknesses (0.50, 0.70 and 1.00 mm), to obtain data such as forming forces or forming fracture lines to be compared against standard forming limit diagrams or against other materials under ISF. Other data like friction during the process was evaluated as well. Fifteen sets of experiments were conducted, using different values of step down (0.10, 0.50 and 1.00 mm) and two forming tools with diameters 10 and 15 mm.

This work has the objective of evaluating the effect of electromagnetic stirring (EMS) used in continuous ingot (CI) in the mechanical and metallurgical properties of hot forged flanges of AISI 1025 steel. Three conditions of raw material were supplied and compared before the forging process: one from CI using EMS; the other, prevenient from CI without EMS, and the last, with CI without EMS, and, subsequently, submitted to hot rolling process. Billets were extracted from these raw materials to manufacture connection flanges through hot forging. To evaluate the mechanical properties of the forged pieces, tension, hardness and impact tests were done, and the microstructure was observed by optical microscopy. Macrographs and penetrating liquid non-destructive testing were also done. The results of the above-mentioned tests showed proximate mechanical and metallurgical properties approved by the reference norm (ASTM A105) of the flanges manufactured with the raw materials obtained by CI with EMS and hot rolling.

Nowadays, different studies on Incremental Sheet Forming have been taken due to the increasing demand for flexible manufacturing processes. This process is applicable in different areas, such as prototyping and the production of small batches of parts, always searching for lower manufacturing costs. This work analyzes how the variation of the process strategies (punch diameter and the vertical step down) influences the workpieces strain ends. These experimental studies were compared to the numerical simulation. The results found show concordance between simulated and experimental results.