Stainless steel sheet stretch wrinkles

Stainless steel products are used more and more widely in many industries due to their exquisite appearance, excellent corrosion resistance, high temperature oxidation resistance and high and low temperature strength.

Due to the high quality requirements of such products, it is very difficult to ensure that the surface of the product with high brightness is not scratched and scratched during the whole processing of the product, especially the mold selection due to the deep drawing characteristics of the stainless steel sheet. Problems such as heat treatment, processing and process lubrication directly affect product quality, output, cost and mold life.

The material selection of the mold working part, for the wrinkle problem, has been proved by practice: the use of cast aluminum bronze, hard aluminum bronze anti-adhesive effect is better; the use of tungsten carbide steel knot hard alloy to make the concave mold is better than the Cr12Mov soft nitriding to improve the die life Several times, and no sticking; if the code is 3054 alloy cast iron, only the surface of the mold is subjected to flame quenching, and no wrinkles appear on the surface of the mold.

The surface processing of the working part of the mold requires high surface quality of the stainless steel drawing die, and the low surface roughness can reduce the friction and improve the anti-adhesion. Therefore, the surface roughness of the mold is reduced, the number of times of grinding of the mold is correspondingly reduced, and the service life of the mold is correspondingly improved.

Process lubrication, from the deep drawing characteristics of stainless steel, the formation of wrinkles is because the sheet and the mold have direct contact, so the first point of choice of lubricant or coating agent is that the lubricant film does not break from the beginning during the sheet deep drawing process and For lubrication. “Anti-sticking and reducing friction” is the basic starting point for selecting lubricants.

Generally, a certain proportion of additives or solid lubricants can be added to the lubricant to achieve better results. This is mainly to improve the lubricating ability of the lubricant to the metal surface, and to produce compounds containing sulfur, phosphorus and chlorine at high temperatures. The metal surface reacts chemically to form iron sulfide, ferric chloride, etc. to enhance the strength of the oil film and enhance the adsorption capacity, and better lubricate the mold and the surface of the product.

The solid lubricant is filled into the small pit of the metal surface to minimize the dry friction contact point. In addition, the solid lubricant has high stability and can also be lubricated at high temperatures, and the mold sticking is less likely to occur. It is usually selected and formulated according to the degree of deformation of the product and the actual situation in the production (the formula can be found in the stamping manual).

In addition, fat, mineral oil, synthetic oil, grease, soap can also form a lubricant, and the effect of shallow drawing on stainless steel is good, containing water-soluble emulsion, or organic mineral oil diluted with oil can also be used for shallow Drawing, adding graphite to the lubricant can play a role in anti-adhesion. However, it is difficult to clean the graphite after adding it. For example, if the mold is made by using the code 3054 alloy cast iron, the general lubricant is better.

According to the data, the sheet material can be obtained by a salt bath to obtain a layer of metal soft mold (such as copper, zinc, lead, etc.), and no sticking phenomenon occurs during deep drawing.

In addition, in recent years, an organic polymer lubricating film mainly composed of polyvinyl butyral has been developed. The blank is treated, and an organic lubricating film is obtained on the surface, which can be deformed together with the sheet, which not only avoids the mold. Direct contact with the sheet prevents the sticking of the mold and ensures the surface quality of the product. Moreover, the friction between the mold and the sheet material is greatly weakened, and the lubricating effect is good, and the experiment shows that the effect is good.

Concerned about surprises

Label: Stainless steel products

Previous: Five Tips for Tapping of Stainless Steel Materials Next: Main Uses of Several Major Stainless Steel Materials