By adding serrations to the bolts, the service life of 8566 die steel is 20 times that of DC53, and mold costs are reduced by 80%.
Last night, I received a message from Mr. Chen: “Hello, General Manager Wu! We verified today that 8566 steel has 20 times the service life of DC53.”
Seeing a 20-fold increase in service life, my eyes lit up, so I asked him, “How many products can 8566 produce now? I remember you said that the original tungsten steel could only produce a little over 10,000.”
Mr. Chen’s mold is used for cold heading fasteners—specifically, carbon steel hex bolts. The process involves forming 68 teeth on the back of the bolt, similar to a lock washer. The forming process requires 150 tons of force. Currently, using tungsten steel, the mold can produce over 20,000 units at peak capacity, but typically cracks after producing just over 10,000. Each mold costs 6,000 yuan, which equates to a mold cost of 2 yuan per product—a cost that is simply too high. The current tungsten steel dies either develop longitudinal cracks at the fillet transitions or suffer large-scale peeling at the 68-tooth areas, with some cases of longitudinal cracking as well. Die life is inconsistent, and the costs are extremely high—we simply cannot sustain this.
Mr. Chen replied that the first DC53 insert lasted only 300+ cycles, while the second one, using your 8566 insert, lasted over 6,000 cycles. Compared to the price of tungsten steel molds, the cost-effectiveness is high.
Cost-effectiveness is what factories strive for, which is a good thing.
I asked Mr. Chen further: “Have you calculated how much the mold cost is allocated per part for 8566 or DC53?”
Mr. Chen added that when tungsten steel molds have a short lifespan, the cost is allocated at 2 yuan per part; on average, it’s around 1 yuan. Based on yesterday’s first use of the 8566 insert, the allocation was approximately 0.2 yuan.
Based on Mr. Chen’s response, DC53 inserts wear out after 300+ shots, while 8566 inserts have a lifespan of over 6,000 shots. The tooling cost per part for tungsten steel molds is around 1 yuan, whereas for 8566 molds, it’s approximately 0.2 yuan.
In other words, the service life of 8566 mold steel is 20 times that of DC53, and the tooling cost is reduced by 80%.
From this perspective, cheap mold steel has a short service life—it becomes scrap after just 300 products—so no matter how cheap it is, it ends up being expensive.
On the other hand, high-performance mold steel may cost a little more per kilogram, but in reality, it lasts 20 times longer and reduces costs by 80%. No matter how you look at it, it’s a better deal.
Sadly, many business owners only focus on the price difference per kilogram; they fail to calculate the total mold cost, let alone consider the expenses of mold machining or the time lost due to mold replacement.
8566 die steel offers four times the crack resistance of high-speed steel SKH-9 and twice that of D2, with a hardness of 58–60HRC . It resolves cracking issues that high-hardness mold steels like D2, DC53, and SKH-9 cannot address; This is particularly true under harsh conditions such as stainless steel stamping, sharp-corner stamping, narrow-flange stamping, and operations where the hole diameter is smaller than the sheet thickness or the stamping ratio is less than 1:1. Cracking issues that standard mold steels cannot resolve are all addressed using 8566 anti-cracking steel.
For cold heading tooth-forming dies with sharp corners, the requirements for crack resistance are extremely high. Tungsten steel has very high hardness and excellent wear resistance, so it is normal for it to crack easily. Moreover, tungsten steel is very expensive, making die costs high; once a die cracks, it is highly uneconomical and results in significant losses.
DC53, on the other hand, is a cold-work tool steel with a carbon content of 1.0% that can achieve a hardness of 60–62 HRC. While it is cost-effective, it is too brittle to withstand impact. The fact that it fails after cold heading just 300 products further confirms that DC53 is unsuitable for cold heading dies with sharp gear corners.
Using 8566 die steel for cold heading applications is like night and day compared to the old approach. For cold heading dies prone to cracking—especially those with sharp corners, such as this toothed lock washer—this steel is the ideal choice. It extends die life by 20 times while reducing tooling costs by 80%. This dual-benefit model of increased longevity and reduced costs is highly cost-effective and unmatched by other tool steels.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.