A viewer in the livestream asked: “The hardness of the 05 high-strength steel is 42 degrees, but now, after machining 10,000 pieces, it keeps developing burrs. What kind of die steel should I use?”
Stamping 0.5mm-thick 65Mn steel sheets with a hardness of 42 HRC involves stamping thin, hard material, which places extremely high demands on wear resistance and the ability to prevent material adhesion. This requires mold steel with high hardness and a high proportion of hard carbide phases—that is, high-carbon, high-alloy mold steel. Currently, the die wears out after only 10,000 stamping cycles. The material used should be cold-work mold steel such as Cr12MoV or DC53; otherwise, it would not wear out so quickly.
For stamping 0.5mm-thick, hard 65Mn steel sheets, 8503 die steel offers the best value for money. We have a customer stamping 1 mm thick windshield wiper components, which are also made of hardened 65Mn steel. The customer informed me that 8503 die steel offers the best cost-performance ratio; PM23 can last at most 10,000 cycles, but PM23 powdered high-speed steel costs five times as much as 8503.
Mr. Zhang also said: “We’re now using 8503 die steel for the punches, and they no longer chip at the corners. The results have been good—we’ve stamped 250,000 products without any chipping. We’ve run out of this material, so we need to buy more.”
Mr. Zhang is stamping 1.0-thick 65Mn steel toothed parts. When he used DC53 for thin-walled, sharp-cornered punches, they chipped quickly. After switching to SKH-9 high-speed steel, the results were still inconsistent—sometimes the punches chipped after 150,000 strokes, and other times after just 2,000 to 3,000 strokes.
Based on Mr. Zhang’s feedback, when stamping 1.0-thick 65 manganese steel toothed parts, thin-walled, sharp-cornered punches made of SKH-9 would chip after just 20,000–30,000 strokes. However, when using 8503 die steel, not only is the price lower, but the punches can withstand 250,000 strokes without chipping—an eightfold increase in service life. This combination of lower cost and eightfold longer service life—offering such excellent value for money—can only be achieved with non-stick 8503 die steel.
8503 is a non-stick mold steel exclusive to Yuhui, with a hardness of 55–61 HRC and chipping resistance twice that of DC53. It offers double the performance without doubling the price, plus the added benefit of non-stick properties. If you’re struggling with punch chipping while stamping thin sheets or hardened thin sheets, you should give 8503 die steel a try—it offers exceptional value for the price.
Of course, if you still feel that 8503 die steel with a hardness of HRC 59–61 is too soft, you can opt for PM23 powdered high-speed steel at five times the price, which has a hardness of HRC 64–66. It offers quite good wear resistance, though it is a bit expensive.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.