As the workday was winding down, I received some good news and wanted to record a video to mark the occasion. When punching 1mm-thick steel at a speed of 200, punches with minimal flange width are prone to breaking, but Yuhui 8566 crack-resistant steel can withstand 1.5 million punches.
Mr. Guo operates a high-speed punch press with a stroke rate of 200, punching 1mm-thick steel. The punch has a 2.0-mm hole, with very little clearance between the hole and the edge—just over one millimeter. Initially, he used DC53, but the punch would chip after only a few products, and this happened every day, bringing production to a standstill. Later, he purchased some second-grade 8566 locally. While it was usable—lasting 7–8 days on a good day—it would sometimes break unexpectedly, causing him a great deal of frustration.
Mr. Guo contacted me a month ago. Given that his punches had narrow flanges with minimal overlap and were consistently experiencing chipping issues, I recommended he use 8566 anti-chipping steel.
8566 offers four times the crack resistance of SKH-9 high-speed steel and twice that of D2, with a hardness of 58–60 HRC. It is specifically designed to address cracking issues that high-hardness die steels like D2, DC53, and SKH-9 cannot resolve. In particular, for stainless steel stamping, sharp-corner stamping, narrow-flange stamping, applications with minimal flange overlap—even where the punch width is less than the sheet thickness and the stamping ratio is less than 1:1—where conventional die steels are prone to chipping, 8566 has proven to be the solution.
Mr. Guo has now informed me that punches that used to break easily can now last half a month when using 8566. At a stamping speed of 200—equivalent to 12,000 strokes per hour—and an 8-hour workday, the daily output is approximately 100,000 units. With 8566, this operation can now run for 15 days, equating to the production of 1.5 million products.
When high-speed punching 1.0-thick steel at a speed of 200, where the products have minimal flash, both DC53 and standard 8566 are prone to breaking, but Yuhui 8566 can last half a month and produce 1.5 million units. I think this result is quite impressive—with such a precise case study and clear comparison—I feel I should record a video to document it.
Mr. Guo told me today that the 8566 he used to buy was very cheap—only 80–90 yuan per kilogram—but it would break after only a short time of stamping. Although it was slightly better than DC53, it still broke, and no matter how many solutions he tried, he couldn’t fix the problem. This time, I bought one of your 8566 products to try it out, and to my surprise, Yuhui 8566 didn’t let me down. The injection nozzles now last half a month, so I don’t have to keep disassembling the molds—it’s much more convenient for me, and my processing costs have gone down. I want to thank you.
8566 is not a national grade; it’s a grade of Yuhui mold steel. It is not a public standard but our intellectual property. However, due to the 8566’s high market visibility, strong sales, and customers specifically requesting it, it has attracted widespread imitation across the industry—not only “four-copy” 8566 but also “shadow” 8566 versions, and it has even become a reference standard for certain major steel mills. This has led many uninformed people to waste their money.
Take Mr. Guo, for example. While the counterfeit 8566 may seem slightly cheaper, its service life is only half as long. The actual cost of use is therefore higher. The loss extends beyond just the purchase price of the counterfeit 8566; it also includes higher machining costs, more frequent mold disassembly, increased labor fatigue, and lower production efficiency.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.