Because stainless steel plate has high yield point, strong hardness and cold hardening effect, there are many characteristics to be noticed when doing deep drawing. First, because the thermal conductivity of stainless steel plate is weaker than that of ordinary low carbon steel, the deformation force is high.
Secondly, when drawing deep, the plastic deformation of the stainless steel plate is hardened and the sheet drawing is easier to wrinkle and the edge pressure is stronger. The third is the springback caused by bending and reverse bending at the fillet corner of the drawing die, which usually causes concave deformation on the side wall of the product, which results in higher dimensional accuracy and shape requirement. The last one is that the stainless steel plate is easy to produce the bond in the drawing process.
And how do you solve the problem?
The first step is to choose the working parts of die materials better, in order to solve the problem of tumor bond practice shows that, with cast aluminum bronze, aluminum bronze, anti sticking effect is better, the use of tungsten carbide alloy die manufacturing than the service life of the die with Cr12Mov soft nitriding improved several times, also won’t stick to die; and such as the use of code 3054 alloy cast iron, as long as the flame quenching on the surface of the mould, mold will not appear on the surface of tumor adhesion.
The surface of the working part of the mold should also be processed. Because the surface quality of the stainless steel drawing die is very high. The lower surface roughness can reduce friction and enhance the adhesion resistance. Therefore, to reduce the surface roughness of the die, the number of molds will also be reduced, which helps to improve the service life of the die.
But also for the lubrication of the process, from the characteristics of stainless steel drawing to understand tumor is due to generation of bonding sheet and the mold have direct contact, so the choice of primary point lubricant or coating agent is in sheet deep drawing process of lubricating film can not break from first to last for lubrication.
A good effect can be obtained by adding a certain proportion of additives or using solid lubricants in the lubricants. This is mainly to enhance the lubricating ability of lubricant on the surface of metal compounds, sulfur, phosphorus and chlorine to form at high temperatures and the metal surface chemical reaction, formation of iron sulfide, chloride, to strengthen the oil film strength and enhanced adsorption capacity, better lubrication and surface mold products.
Solid lubricants are filled into small pits on the metal surface, so that the dry friction contact points are reduced to a minimum. In addition, solid lubricants are highly stable, and can also play a lubrication role at high temperature, and die bonding is not easy. In general, different proportions are selected according to the deformation degree of the product and the actual situation in the production.
Source: China Stainless Steel Plates Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)