A viewer named Deng Sheng asked in the live stream: “Punching and blanking 3mm-thick T2 red copper sheets tends to cause burrs. Could you recommend materials for the upper punch and lower die? We’re currently using DC53.”
Burrs during the stamping of red copper sheets are caused by adhesive wear resulting from material adhesion. Since red copper sheets are not particularly hard, the dies do not require high hardness; instead, they need to have non-stick properties.
DC53 is a high-carbon steel with a carbon content of 1.0%. Poorly smelted DC53 suffers from severe segregation and contains a large number of microscopic cracks invisible to the naked eye. When these microscopic cracks come into contact with soft red copper during stamping, copper permeation occurs, leading to sticking and burrs on the product. The solution is to select a die steel that prevents material adhesion.
Mr. Deng asked about punching and blanking 3mm-thick T2 copper sheets; using DC53 tends to cause burrs. There are two solutions:
1) Apply a coating to the existing DC53 to improve surface finish. The coating will cover the steel’s inherent microcracks, resolving the issue of copper adhesion and eliminating burrs.
2) Switch to 8566 die steel. Yuhui’s 8566 is produced through high-quality smelting in a critical gas electroslag furnace, resulting in low impurity content. It undergoes six-sided forging on a 4,500-metric-ton press—with three forging and three drawing passes—ensuring uniform microstructure and eliminating segregation and microcracks. This naturally prevents copper powder adhesion. Additionally, 8566’s high thermal conductivity allows heat generated during stamping to dissipate quickly, further reducing the risk of copper powder adhesion.
Mr. An is stamping 1.55mm-thick 62 copper electrical plugs. He uses DC53, SKH-9, and D2 punches, but after several thousand strokes, copper powder adheres to the scrap material, causing damage to the products. Mr. An reported today that the 8566 punches he purchased from you last time for copper stamping performed very well—they lasted for 300,000 strokes without requiring any die repairs.
These two solutions apply to both punches and dies.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.