Formability tests

There are many metal forming processes: rolling, drawing, extrusion, stamping, forging, etc. To obtain good results, it is important to use sufficiently powerful tools and to limit deformations to avoid the formation of defects such as tears. Tests have therefore been developed to ensure that these conditions are met. They can reproduce the intended shaping process more or less faithfully. However, with the development of increasingly sophisticated and easy-to-use numerical calculation tools, it is often more convenient and cost-effective to use computer-aided design.

These calculations require knowledge of the material's behavior laws. These can only be determined by testing. When it comes to shaping, processes are unique in that, on the one hand, plastic deformations can reach large amplitudes, and, on the other, they are often carried out at high temperatures and speeds. This makes it difficult to use tensile tests, which are disrupted too early by striction. In such cases, it makes sense to use compression tests.

However, the torsion test proves convenient to use. Its use can be recommended for determining hot behavior laws. Compression tests have already been described in the files devoted to the determination of behavior laws. , we will confine ourselves here to the presentation of hot torsion tests. Simulation tests for forming processes are extremely varied. In general, they are not standardized. We'll concentrate here on stamping tests. In order to understand the differences between them, we will begin by analyzing the biaxial expansion test using oil pressure and the swaging test, which represent two contrasting situations. This is followed by a description of a number of other tests. Although not all of them are commonly used, they are at least of historical interest. Finally, the bending test, which provides useful qualitative indications while being particularly simple to perform, will also be described.