Six years later, Mr. Wei, who had purchased 8566 die steel in 2020, returned to buy more 8566 die steel.
His first words were, “8566 die steel is a bit pricey, but the products produced through hot forging are truly beautiful—the surface finish is excellent. Of all the die steels I’ve used, none compare to it in terms of quality.”
Mr. Wei specializes in hot-forging 45 steel profiles. His dies are secured with an outer sleeve. In July 2020, when he first encountered 8566 die steel, he purchased two pieces of 8566 and tested one of the dies. The results were excellent, but due to pricing concerns, our collaboration was put on hold.
Currently, we’re using GR die steel, but it’s prone to cracking and flaking off in pieces. With customers demanding ever-higher surface finish standards, the dies crack quickly, become scrap rapidly, and incur high costs. Constant die repairs prevent us from increasing production, so we’re considering switching back to 8566 die steel.
8566 is a proprietary product of Yuhui Mold Steel. Its heat resistance is comparable to that of SKH51 high-speed steel, with a hardness of 58–60 HRC and four times the toughness of SKH51. 8566 mold steel strikes the perfect balance between high heat resistance, high hardness, and high toughness. With its high heat resistance and hardness, 8566 exhibits excellent resistance to thermal wear, resulting in products with superior surface finish.
Additionally, with toughness four times that of SKH51, this mold steel demonstrates excellent resistance to thermal fatigue, making it less prone to cracking under rapid cooling and heating conditions. Furthermore, 8566 is produced via critical gas electroslag remelting, resulting in high purity and low impurity levels. It undergoes six-sided forging—three forging and three drawing passes—which ensures uniform microstructure, high density, and finer grain size, naturally yielding products with a bright finish.
GR, on the other hand, is a tungsten-containing hot-work die steel. Materials containing tungsten generally have lower toughness and are prone to thermal fatigue cracking under rapid cooling and heating conditions, which affects product surface quality and can even lead to chipping and spalling. The fact that his GR die steel is currently flaking off in patches further illustrates this point.
Products hot-forged from 8566 exhibit excellent surface finish. This is not just Mr. Wei’s opinion; Mr. Zhang from Zhejiang also gave 8566 a five-star rating for hot-forging 304 stainless steel, noting that the surface finish is excellent and the finished product looks just like one made from a tube.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.