During last night’s 298th live stream, a viewer asked which die steel would be more durable for machining 0.6 301 stainless steel. Currently, they’re using SKH-51 high-speed steel, but it breaks easily.
The product has sharp corners and is a hard material; combined with these three factors, the first material that comes to mind is 8566 chipping-resistant steel.
8566 die steel offers four times the chipping resistance of SKH-9 high-speed steel 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. In particular, for stainless steel stamping, sharp-corner stamping, narrow-flange stamping, and thick-sheet stamping—especially in narrow-flange conditions where the punch width is less than the sheet thickness or the stamping ratio is less than 1:1—chipping issues that standard die steels cannot resolve are all addressed using 8566.
Our customer, Mr. Liu, was stamping 0.4-thick 304 stainless steel—a hard material with a hardness of 400 HV and a relatively complex product structure featuring narrow edges. He used 8566 to perform 150,000 stamping cycles without experiencing any fractures or wear issues. Mr. Liu was very pleased.
Regarding the 0.6-thick 316 stainless steel mentioned by this user—a material with some hardness and sharp corners—SKH51 is prone to fracture under these conditions. Since the die conditions are similar to Mr. Liu’s, 8566 anti-chipping steel can resolve the issue; this is precisely the type of application where 8566 excels. Using 8566 die steel for punch chipping makes all the difference—it’s like night and day.
Second option: If you feel that 8566 is too soft and prefer a higher hardness, then go ahead and pay three times the price for PM23 powdered high-speed steel.
PM23 has a hardness of 64–66 HRC. Thanks to advanced powder metallurgy processes, this die steel offers both high hardness and high strength. PM23’s resistance to chipping and wear is 2–3 times that of SKH-51.
We have a customer who stamps 1.5 304 stainless steel into 1.5 × 2 mm narrow strips. The original die was a major headache—a set of punches and dies could only produce a maximum of 50,000 parts before burrs appeared, and the resulting metal shavings even damaged the products. After he contacted me, I recommended he use PM23.
The results with PM23 were excellent—they could now stamp 200,000 products in a single run without damaging the parts. PM23 increased the die life from the original 50,000 strokes (which included damage issues) to 200,000 strokes, effectively quadrupling the service life.
Regarding the 0.6-thick 301 stainless steel with sharp corners that this viewer mentioned—SKH51 is prone to breaking in such cases. If you don’t want to use 8566 chipping-resistant steel, then spending three times as much on PM23 is a perfectly viable option.
Since I couldn’t see the product’s structure during the livestream, I could only offer him these two material options. The specific choice of mold steel is up to the viewer to decide; they should weigh their options based on their mold’s production cost.
I don’t sell products in the livestream, so there’s no need to send virtual gifts. If you have questions about mold steel, feel free to ask. As long as you clearly describe the mold’s operating conditions, I’ll definitely provide you with 2–3 material selection suggestions. You can then choose the appropriate mold steel grade based on your mold’s cost and service life requirements. This way, you won’t be torn between options, won’t take any detours, and won’t have to learn the hard way.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.