Twenty days later, we received good news about 8566. Mr. Zhang said that using 8566 for punches has doubled their service life, and the results are satisfactory.
On April 18, 2026, Mr. Zhang asked: “Hello, are there any good materials for making punches that are wear-resistant and won’t break?”
After further discussion, we learned that he was using a 250-metric-ton pneumatic punch press for hot forging hollow products. The parts required a red forging punch with an inner diameter of 33 and a height of 100. The inner-bore punches were not holding up to the work, and while he was currently using GM3, GM5, and 1.2367, the results were inconsistent—the punches tended to wear down into rounded corners or develop wire-drawing marks.
After speaking with him, I recommended that he use 8566 die steel, which offers high heat resistance, high hardness, and high toughness.
The main issues with his current punches—die collapse and wire drawing—are caused by annealing. To address these, he needs to improve the punches’ heat resistance, hardness, and resistance to thermal wear; therefore, I recommended 8566 die steel, which offers high hardness, high heat resistance, and high toughness.
The heat resistance of 8566 die steel is comparable to that of SKH51 high-speed steel; it has a hardness of HRC 58–60, and its toughness is four times that of SKH51. 8566 strikes the perfect balance between high heat resistance, high hardness, and high toughness, whereas other die steels cannot simultaneously achieve these three characteristics. Therefore, when 8566 is used for hot forging of stainless steel, it does not collapse, crack, or wear out easily, resulting in a long service life.
Regarding the hot forging of 304 stainless steel, Mr. Zhang gave 8566 a five-star rating, noting that the product’s surface finish is excellent and that the finished product looks just like one made from a tube.
But after our conversation, we heard nothing more. It wasn’t until September 11 that Mr. Zhang finally placed an order for 10 pieces of 8566 round bar to make hot-forged punches.
This afternoon, 20 days later, Mr. Zhang called to say: “The 8566 punches are working well. We can now produce about 8,000 pieces, compared to the previous 4,000 that were only rounded and brushed. The improvement is significant—it’s definitely making a difference.”
Based on Mr. Zhang’s feedback, the 8566 punches have doubled their service life from 4,000 to 8,000 pieces.
I can tell from Mr. Zhang’s enthusiasm that, for high-volume production like ours, what matters most is long punch life—not the low price of die steel. As long as the punches perform consistently, improve production efficiency, and produce the desired products, even the most expensive die steel is worth the cost and a sound investment.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.