Stainless steel plate can be used to make a lot of daily necessities, stainless steel processing technology is diverse, such as stamping, bending, shear folding, etc., this paper focuses on stamping process. The common stamping forming processes of stainless steel sheet include drawing process, bulging process, flanging process (including reaming) and bending process. The corresponding material properties are bulging forming performance, flanging formability, reaming formability and bending formability.
But before talking about the stamping process of stainless steel plate, the two factors that will affect the mechanical properties of stainless steel are also discussed. They are internal cause and external cause respectively. Internal causes are more important, that is, different chemical elements in stainless steel tissue, mainly metal elements, different types of stainless steel because the chemical composition is different, so the strength is also different.
There are generally three factors, the first is the deformation temperature, and under normal conditions, the strength is increased when the temperature is lower. For austenitic stainless steel, the decrease of temperature will make the plasticity decrease little, so it has better impact toughness at low temperature. For ferritic stainless steel, the temperature drop will greatly reduce the plasticity, so there is a low temperature brittleness. It’s just ordinary. When the temperature drops, the internal structure of stainless steel will be changed, and the abnormal phenomenon will also occur. A large number of stacking faults occur in the CrMnN stainless steel under low temperature impact, so there is a significant ductile brittle transition phenomenon. For example, 304 stainless steel bars with low carbon, chromium and nickel content will form martensite at low temperature, which will also reduce impact toughness.
The second is the deformation velocity. Generally speaking, increasing the deformation rate will reduce the toughness. For example, the temper brittleness that can not be reflected by tensile properties can be shown by impact toughness. Ferrite at the pulse speed causes ferrite free phase transformation and twinning, which will decrease the toughness of ferrite.
The third is the state of stress, the sample with notch, crack and sample thickness will change the stress state and stress concentration, thus affecting the toughness of stainless steel material.
It is because of the above mechanical properties of stainless steel material, so the processing is based on the actual needs and material properties to do targeted programs. The stamping process of stainless steel plate is introduced as follows.
Drawing process, which is a kind of stamping process method using the special mold to cut or cut the flat blank to open hollow parts. Its characteristic is that the stainless steel sheet can flow into the die under the driving of the punch, that is to say, the material is formed by the fluidity and elongation of the material.
Bulging forming process is to use the mold to force the thickness of the blank thinning and surface area increase, so as to get the geometry of the workpiece stamping method. It is characterized by that the blank is crushed by the blank holder and can not flow into the die. It is completely dependent on the extension of the material itself.
Flanging forming process is a stamping process which uses the mold to turn the hole edge or the outer edge of the blank into the vertical edge. In the middle stage of the round hole flanging, that is, the material under the punch has not been transferred to the side. If the deformation is stopped, the forming method will be shown on the right. This forming method is called reaming and is widely used in production.
The last bending forming process is actually a forming process for bending the stainless steel sheet, bar, tube or profile into fixed shape and angle parts.
Source: China Stainless Steel Plate Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)