What’s the best material for stamping 3mm stainless steel? We’re currently using Cr12MoV, as asked by a viewer during the 300th live stream.
Stamping 3mm stainless steel involves stamping thick, hard material. The stamping process generates significant vibration, which can easily cause the punch to fracture or the retainer to snap. Cr12MoV is too brittle—it is bound to fracture. You must use 8566 anti-fracture tool steel. Using 8566 tool steel for punches makes a world of difference compared to the old method.
Cr12MoV is a high-carbon steel with a carbon content of 1.5%. As a high-carbon, high-chromium cold-work die steel, after heat treatment, its microstructure contains a large number of microscopic cracks invisible to the naked eye. During stamping vibrations, these microscopic cracks propagate. Once the propagation accumulates to a certain extent, breakage or chipping occurs. Furthermore, high-carbon die steels inherently lack impact toughness. When using Cr12MoV to punch 3mm-thick stainless steel, the punch will either break at the tip or snap at the shank—making it completely unusable. For punching 3mm-thick stainless steel, I recommend 8566 anti-chipping steel.
8566 offers four times the chipping resistance of high-speed steel SKH-9 and twice that of D2, with a hardness of 58–60 HRC. It is primarily designed to address chipping issues that high-hardness die steels such as D2, DC53, and SKH-9 cannot resolve. This is particularly true for stainless steel stamping, sharp-corner stamping, thick-sheet stamping, fine-blanking dies, and even narrow-flange stamping—where the punch diameter is smaller than the sheet thickness and the stamping ratio is less than 1:1. Chipping issues that standard die steels cannot resolve are all addressed by 8566.
I recall Mr. Chen mentioning that using 8566 to punch stainless steel yields satisfactory results; it can easily handle 30,000 punches when blanking 3mm-thick stainless steel.
Additionally, Mr. Li was punching four 6.8mm × 6.8mm square holes in 4mm-thick 201 stainless steel. With the original DC53 punch, after punching 800–1,000 parts, the tip of the punch would snap clean through the middle. Every time Mr. Li received this order, he had to cut a whole basketful of punches and have a technician stand by the press to replace them at a moment’s notice. This customer was also left with no choice but to place orders with four suppliers simultaneously—all four had to deliver at the same time to meet production demands.
However, after Mr. Li secretly switched to Yuhui 8566 anti-fracture steel, the punches stopped fracturing. He consistently delivered the largest quantities on time for each order, and eventually, the client awarded him all orders for this product. He told both the client and his peers, “I’m using DC53 punches too, but mine are of higher quality—they undergo a special heat treatment process that prevents fracturing.” Both his client and industry peers began to look at him with newfound respect.
Mr. Li told me: “The 8566 chipping-resistant steel not only solved my punch chipping problem and improved production efficiency, allowing me to secure orders I wouldn’t have otherwise, but it also let me hold my head high in front of my customers and peers.”
If you’re stamping 3mm stainless steel using Cr12MoV, SKD11, DC53, D2, or SKH-9, the punches are bound to crack—there’s no way to prevent it. You should give 8566 anti-cracking steel a try.
Use 8566 die steel for punch cracking. It’s like night and day compared to the old methods.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.