The reason why the forming properties of stainless steel plates of different steel types vary greatl

The forming performance of stainless steel plates will vary greatly depending on the respective steel types. This is due to differences in the crystallographic structures of each. For example, the forming properties of ferritic stainless steel and austenitic stainless steel are very different, because the crystal structure of the former is body-centered cubic, while the crystal structure of the latter is face-centered cubic, so naturally the forming properties of the two are obviously different. difference.

The flange forming performance of ferritic stainless steel is related to the n value, and the deep drawing processing performance is related to the r value. The r value is determined by different tissue sets under different production processes. Using some measures to significantly reduce solid solution carbon and solid solution nitrogen can greatly optimize the r value and greatly improve the deep drawing performance of stainless steel plate materials.

Generally speaking, austenitic stainless steel has a relatively large n value. During the processing process, martensite is formed due to plastic induced phase transformation, so it has a relatively large n value and elongation, and can be used for deep drawing and processing. Flange forming. Some austenitic stainless steels will form longitudinal cracks consistent with the stamping direction over a period of time after deep drawing, which is what people call age cracks. For this purpose, the use of high-nickel, low-nitrogen and low-carbon austenitic stainless steels can effectively prevent the formation of this defect.

The nickel element contained in austenitic stainless steel can significantly reduce the cold work hardening tendency of the stainless steel material. The reason is that it can strengthen the stability of the austenite structure, reduce or remove the martensitic structure transformation during cold working, and reduce the risk of cold working. Hardening rate, strength decreases and plasticity increases.

Increasing the nickel content in duplex stainless steels reduces the martensitic transformation temperature, thereby improving cold working deformation properties. When evaluating the formability of stainless steel plates, the comprehensive formability is usually used as a symbol. The comprehensive molding performance is composed of fracture resistance, deep drawing performance, flange forming performance, edge extension performance, and bending performance that indicate the fracture limit, wrinkle resistance that indicates the compatibility between the forming mold and the material, and also indicates that after unloading Fixed shape, shape fixity, etc.