Search Results (12)

This study explores the development of Al-Mg alloy sheets manufactured through the Twin Roll Continuous Casting (TRC) technique, with the goal of enhancing their mechanical properties via thermomechanical processing. TRC is a cost-effective and efficient method for producing thin sheets directly from molten metal, and this work focuses on the deep drawability of AA5182, AA5754, and AA5052 alloys, widely used in automotive, packaging, and aerospace applications. Improving deep drawability is crucial for meeting the stringent requirements of these industries. The alloys were designed according to EN 573-3 standards, and sheet castings were carried out at both laboratory and industrial scales. Microstructure evolution was analyzed at the as-cast and final thicknesses using optical microscopy. The sheets underwent cold rolling to a thickness of 1 mm, followed by final annealing, and their mechanical properties—including yield strength, tensile strength, elongation, and anisotropy—were evaluated. The deep drawability of the sheets was assessed using Erichsen cupping tests and earing mechanisms. To further understand failure mechanisms, fracture surface morphologies were examined using scanning electron microscopy (SEM), while energy-dispersive X-ray spectroscopy (EDS) was performed to analyze inclusions on fractured surfaces. The findings highlight the effectiveness of the TRC technique in producing high-performance Al-Mg sheets with mechanical properties comparable to or exceeding those of conventionally processed sheets. This study provides valuable insights into the optimization of alloy design and manufacturing methods, laying the groundwork for future advancements in TRC technology. Full article

One of the main problems during sheet metal forming is the reduction in coefficient of friction and separation of contact surfaces in order to eliminate buildups of the formed material on the forming tools. For this purpose, technological lubricants based on mineral or synthetic oils are usually used. Unfortunately, their removal from the drawn parts and their subsequent utilization pose many problems and are expensive. Environmentally benign lubricants based on vegetable oils with the addition of boric acid could be an effective alternative to lubricants based on mineral and synthetic oils; however, the solubility of boric acid in oils is limited. Therefore, the paper proposes new, effective, and environmentally friendly methods for applying boric acid to the metal sheet by spraying it on a thin rapeseed oil layer previously applied to the metal sheet or by spraying a 25% solution of boric acid in methyl alcohol onto the sheet. The effectiveness of such lubrication was assessed on the basis of the so-called strip drawing test, Erichsen cupping test, and formation of cylindrical drawn parts in industrial conditions. The tests showed that the addition of boric acid was most effective for forming the DC01 steel sheet, reducing the coefficient of friction by about 60% compared to base oil lubrication. Although its usefulness is lower in the case of other frictional pairs, it eliminates the phenomenon of the formed material sticking to the tool, thus extending the life of the forming tools. The use of the proposed solution reduces production costs and indirectly boosts environmental protection. Moreover, an explanation of the tribological mechanism contributing to the lubrication action of boric acid is given. Full article

Incremental sheet forming (ISF) requires no or partial dies for sheet metal fabrication and is widely used for small batch production. In this process, necking is either suppressed or delayed due to the localized nature of tool–sheet contact; hence, more strains than conventional stamping and deep drawing are obtained. In the present study, two variations of ISF, namely cold ISF (CISF) and warm ISF (WISF), are compared. First, FEA modeling is carried out on ABAQUS to reach the forming forces involved in the process. It is found that WISF reduces the forming forces. The temperature for WISF is maintained at 180 °C. Following the simulation analysis, tests are carried out. The forming force in WISF is 55.77% less than that in CISF. The part fabricated by CISF is slightly more substantial than that by WISF; however, more forming depth can be achieved by WISF. There is a more uniform thickness distribution in the case of CISF than in WISF. However, the surface quality of the CISF product is inferior to that of WISF. It is observed that there is reduced forming force, increased formability, and better strain distribution in WISF compared to CISF. However, post-processing heat treatment and surface polishing of the formed parts is required to restore their mechanical properties. Full article

Friction, wear, and lubrication are inherent to all metal-forming processes. Unfortunately, they are particularly troublesome when forming titanium materials, which tend to form titanium buildup on the working surfaces of the forming tools. Lubrication is one of the most effective ways to separate contacting surfaces and eliminate galling, thus reducing tool wear. The paper presents the tribological aspects of titanium sheets forming using environmentally friendly lubricants with the addition of boric acid. The lubricant’s effectiveness was assessed on the basis of technological tests, such as the strip drawing test, the Erichsen cupping test, and the formation of spherical drawn parts in industrial conditions. Moreover, the results of the numerical simulation of forming a titanium hat-shaped part are presented. Numerical calculations of forming processes were performed using the PamStamp 2G system based on the finite element method. Both experiments and numerical analyses showed the positive effect of lubricants with boric acid on sheet titanium forming. Full article

UV-curable coatings have numerous advantages, including environmental sustainability due to 100% solid content, economic feasibility attributable to relatively fast curing time, decent appearance, mechanical properties, chemical resistance, and abrasion resistance. However, UV-curable polyurethane acrylate coatings on metals apparently restrict their engineering applications owing to low mechanical properties and poor thermal stability, giving UV-curable coatings less flexibility and formability. In this study, we evaluated the property change of films according to the type of reactive diluents that lowers the viscosity of UV-curing coatings for pre-coated metal and has a substantial effect on the curing rate, viscoelastic properties, adhesive properties, and flexibility of the film. Moreover, there are many changes in the properties of coatings according to varied curing conditions in order to evaluate the oxygen inhibition phenomenon during the curing process in the atmosphere. In particular, to evaluate the effect of reactive diluents on forming formability, which is the most crucial property for the pre-coated metal, this study used conventional formability tests, such as t-bending or the Erichsen test. Moreover, a cross-die cup drawing mold with a similar form as failure and Safety Zone was utilized in order to obtain clearer information on its actual formability. The analysis on the effect of failure and safety zone on the material used in press forming was conducted by assessing limit punch height and forming a limit diagram of the manufactured film according to varied reactive diluents. Full article

The article deals with DIC (Digital Image Correlation) tests on steel plates used in the automotive and railway industries, as well as in the construction industry. The most critical part of DIC tests is the quality of proper surface preparation, painting, and random patterns. The paint mediates the deformation of the optical systems, and its quality is paramount. The authors’ goal in this research is to determine the optimal dye–cleaning–drying time parameters for DIC studies. Commercially available surface preparation and cleaning agents were tested alongside commercially available spray paints. Standard and specific qualification procedures were applied for the measurements. Once the appropriate parameters were determined, the results were validated and qualified by GOM ARAMIS tests. Based on the results, DIC measurements can be performed with higher accuracy and safety in laboratorial and industrial conditions, compared to the traditional deformation measurements executed by dial gauges or linear variable differential transformers. Full article

Aiming at the enhancement of the lightweight formability potential of aluminum alloy, the bulging and tensile properties of a 5052 Aluminum alloy sheet were tested on a microcomputer controlled sheet metal forming tester and tensile testing machine. The effects of different blank holder force, punch velocity and lubrication conditions were investigated on bulging properties by the experimental analysis. The cupping values (Erichsen Cupping Index: IE) of sheets with a thickness of 1.2 mm at room temperature were obtained under different process parameters. Meanwhile, the anisotropic property of the material was analyzed in different rolling directions. The results show that the sheet cupping values increase with the increase of blank holder force and punch velocity, and the stress state was changed due to the changing of the blank holder force and strain rate. Moreover, the use of lubricating conditions with a lower coefficient of friction allows the sheet to exhibit a larger cupping value. The effect of rolling direction on the anisotropy of 5052 aluminum alloy sheet is distinct, which means in the aluminum alloy sheet forming process the anisotropy factor should be carefully considered. Full article

The stretch formability behavior of an AZ61 magnesium alloy plate produced by multi-pass friction stir processing (M-FSP) was investigated, with the applied load vs. displacement curves recorded during Erichsen cupping tests at different punching speeds at room temperature. The stretch formability of M-FSP AZ61 magnesium alloy was significantly enhanced, compared with that of its cast counterpart. The highest Erichsen index of 3.7 mm was obtained at a punching speed of 0.1 mm/min. The improved stretch formability was mainly attributed to the grain refinement stemming from the M-FSP and the presence of extension twinning to accommodate deformation during Erichsen cupping testing. Full article

In this study, a new-generation high-strength and high-ductility medium Mn steel (0.1C-5Mn-Fe) for the automotive industry was joined by the fiber laser and gas tungsten arc welding (GTAW) methods. Formability testing of the welded joints was done by the Erichsen cupping test and finite element (FE) analysis. The results showed that the formability of medium Mn steel welded joints was sensitive to the welding parameters and inferior to that of the base metal (BM). The hardening zone (HZ) was formed in the welded joint, which was composed of the fusion zone and two symmetrical parts of the heat-affected zone. The width of the HZ was one of the primary factors affecting the formability of the welded joints, while the tensile strength and ductility of the HZ were secondary factors. FE simulation of the Erichsen cupping test results indicated that the forming strain of the welded joint with narrow HZ concentrated on the BM, while the forming strain of the welded joint with wide HZ concentrated on the HZ. The HZ strain reached the deformation limit first due to its weak ductility; therefore, the welded joint with wide HZ had the worst formability. It was also observed that adopting high-velocity and high-laser power welding could greatly improve the formability of the welded joint as a result of reducing the width of the HZ. Full article

The material characterization regarding sheet metal formability is usually assessed by the forming limit curve (FLC). The FLC requires specialized and expensive equipment, several samples with different geometries, and can be a very time-consuming procedure for data treatment. Alternatively, the hole expansion test (HET) and the Erichsen Cupping Test (ECT) can be used for routine evaluations of sheet metal mechanical behavior. These formability tests require fewer quantities of material and easy specimen preparation with a fast analysis of results. The HET and ECT procedures provide a proper evaluation of sheet material stretch-flangeability, formability, strength, and ductility. In this work, we developed a low-cost mechanical device capable of performing the HET and ECT tests using a universal testing machine. The equipment is designed to meet the test parameters set by ISO 16630 (HET) and ISO 20482 (ECT) standards. In order to verify its functionality, tests were carried out with the dual-phase steels DP600 and DP780. The corresponding values determined for the hole expansion ratio and the Erichsen index provided reliable results in terms of the accuracy and repeatability of the proposed testing device. Full article

Tailor welded blanks (TWB) represent an anisotropic and non-homogenous material. The knowledge of the mechanical properties and microstructure of the fusion zone and heat-affected zone (HAZ) obtained with laser welding is essential to ensure the reliability of the process. In this paper, laser-welded hot-dip Zn-coated low carbon microalloyed steels with different thickness and mechanical properties were used. The mechanical properties of the laser-welded blanks were determined by tensile tests and formability by Erichsen cupping tests. In addition, the pore formation during the laser welding process was analyzed. The microstructural analysis confirmed the formation of the favorable structure of the weld metal and the heat-affected zone without the presence of martensite. The obtained results showed that it is possible to produce TWBs with suitable mechanical properties by laser welding. Full article

In this study, the deep drawability of SAE 6114, being a low carbon steel, was investigated. The materials with thickness varying from 0.67 mm to 2 mm were subjected to tensile tests and then R (average vertical anisotropy coefficient) and n (stain hardening exponent) values were determined. At the same time, h (the height of the cup) and F (the reaction force) values of the materials were found by subjecting them to Erichsen test A sheet with 2 mm thickness was cold rolled in 6 different deformation ratios and the tests were applied to it Results obtained from the tests were compared with each other and ANN application was performed for these results.
It was proved that, there was an ANN solution to obtain new values of % deformation rate and thickness properties of deep drawing of low carbon steel sheets which were found by experiment The obtained values satisfied our estimation. Full article