When selecting stamping die steel, many people worry that the steel’s hardness is too low and its wear resistance insufficient. Even though the primary cause of die failure is chipping, they still worry that low-hardness die steel lacks sufficient wear resistance. This is worrying about wear resistance when they shouldn’t be, while neglecting the toughness they actually should be concerned about.
Take the owner of a punch manufacturing plant who came to me today to inquire about 8566 anti-chipping steel. His customer was punching 9.0mm holes in 5mm stainless steel, and he had been using SKH-51 and M42 punches—both of which were prone to breaking, even after increasing their hardness. He heard from his client that 8566 anti-chipping steel has excellent resistance to chipping. He also knows that 8566’s chipping resistance is four times that of high-speed steel SKH-9 and twice that of D2, with a hardness of 58–60 HRC. It can solve chipping problems that high-hardness mold steels like D2, DC53, and SKH-9 cannot resolve.
He had also heard that 8566 anti-chipping steel works very well for stamping stainless steel, but he was still concerned that with a hardness of 58-60 HRC, and whether it would wear out after producing only a few parts. Although he currently has customers stamping stainless steel who purchase 8566 material from me, and customers who come to him for punch grinding have reported that 8566 performs very well when stamping stainless steel, he begins to worry about 8566’s wear resistance when he has to pay for it himself.
8566 is primarily used for stainless steel stamping, sharp-corner stamping, narrow-edge stamping, and even applications where the hole diameter is smaller than the sheet thickness or the stamping ratio is less than 1:1. It resolves chipping issues that standard die steel cannot handle.
Mr. Wang was punching 8.0mm mesh holes in 5mm 304 stainless steel, with 6,000 holes per sheet. He had previously tested punches made from ASP60, ASP30, 3V, and DC53, but they all broke—one after another. He said, “I have to punch 6,000 holes per sheet. If I have to keep swapping out punches, I can’t keep up with production.” However, after switching to punches made from Yuhui 8566, he punched 36,000 holes without any breakage issues.
Many of our customers face this situation: when selecting stamping die steel, they focus solely on wear resistance. Even though the failure mode is chipping, they insist on using high-hardness steel. When chipping occurs, they lower the hardness—even after reducing it to 58 HRC, the punch still chips—yet they remain concerned that 8566 steel in the 58–60 HRC range might lack sufficient wear resistance. Those who haven’t used 8566 have all sorts of worries, but those who have actually used it know that punch chipping is a common issue. Using 8566 die steel makes all the difference—it’s like night and day.
You’re punching 9 holes in 5mm stainless steel—this is thick, hard-material stamping, which generates significant vibration. High-speed steel with excellent wear resistance is too brittle; the punch will shatter from the vibration. This is a material selection error. For thick, hard-material stamping, the punch must prioritize crack resistance; a hardness of 58–60 HRC is actually sufficient. If you let the punch wear down naturally, it will still be capable of producing many parts. Its service life will definitely be longer than that of your current high-wear-resistant SKH51 or M42 punches. Mr. Wang has already verified this—the punch remained intact after 36,000 strokes. Therefore, I still recommend using 8566 anti-fracture steel for your punches.
When punching stainless steel and the punch head fractures, using 8566 die steel makes all the difference.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.