“What type of tool steel should be used for drawing dies to prevent wire marks?” This has been a frequently asked question recently in live streams and by online users. Some people use Cr12MoV+TD or other coatings for their drawing dies, but string marks appear after producing only a few parts. Others even use DC53 with a surface coating, yet string marks still form easily. This has left many people puzzled, unable to identify the cause or determine which die steel to use. Today, I’m making a video to explain which die steel is best for drawing dies to prevent string marks.
The formation of wire marks on drawing dies is generally due to poor metallurgical quality of the die steel, which contains a large number of microscopic cracks invisible to the naked eye. When the die comes into contact with the part during drawing, adhesive wear occurs, leading to the formation of wire marks.
Although coating can cover some of these microscopic cracks on the surface and help resolve this stringing issue, in cases where the die steel suffers from severe segregation and an excessive number of microscopic cracks, the coating cannot fully mask them—and thus fails to solve the stringing problem.
Furthermore, coating is an extremely costly process—for example, TD treatment costs 80.00 per kilogram. This coating cost far exceeds the price of the die steel itself. If wire-drawing issues arise, the die must be sent back to have the coating removed and the process repeated, which is not only a waste of time but also very costly and troublesome. That’s why many people ask me which die steels are less prone to wire-drawing issues in drawing dies.
Based on the performance requirements for drawing dies and successful case studies from past users, I’d like to recommend three types of die steel here.
First: If you’re drawing ferrous materials, use wear-resistant steel 6077 or non-stick 8503 die steel with a hardness of HRC 60–63.
Second: If you’re drawing stainless steel, the die dimensions aren’t too large, and you want the die steel to have a higher hardness, then you can choose Yuhui SKH51 high-speed steel or PM23 powdered high-speed steel, which has superior smelting quality, with a hardness of HRC 62–66.
Of course, when making drawing dies, if your budget allows and you can afford cemented carbide, it is definitely the most ideal choice.
If you’re drawing iron materials, have strict cost control requirements, and want to avoid wire drawing, then wear-resistant steel 6077 and non-stick 8503 are good choices. For the next level up, you can use SKH51 high-speed steel or PM23 powdered high-speed steel. For top-tier performance, go straight for cemented carbide.
The specific choice of die steel depends on a comprehensive evaluation of the die’s structure, dimensions, and production costs. However, regardless of which die steel you use, preventing wire drawing in drawing dies is a top priority. This means the die steel you purchase must be of high metallurgical quality—free of segregation and microcracks—as these are prerequisites for use in drawing dies.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.