Question from a viewer in the live stream: What type of die steel is suitable for drawing? I’m cold rolling 1mm-thick material, and there are always drawing marks.
Stretch dies are most susceptible to stretch marks, and die steel of poor smelting quality is also most prone to them. He is currently drawing 1 mm-thick cold-rolled sheet, and drawing marks keep appearing. This indicates a problem with the material used for his die; the microstructural uniformity is certainly very poor, and the die steel likely has segregation and fine cracks—otherwise, the marks wouldn’t keep appearing. Alternatively, he may be using substandard die steel, such as Cr12MoV, in which case drawing marks are inevitable.
Stretch marks on drawing dies are an extremely common phenomenon; I encounter this situation every other day or so. A couple of days ago, Mr. Liu also came to consult me. He’s drawing 0.35-thick cold-rolled sheet and is currently using Cr12MoV. A small die core is sticking to the material, which increases friction. After polishing, the issue goes away, but the material sticks to the die after just 300 products. What’s the cause?
Stringing in drawing dies is a classic case of adhesive wear caused by material adhesion. You need to use die steel with high-quality smelting and no microcracks. I’d like to recommend a high-value-for-money drawing die steel—Wear-Resistant Steel 6077. Not only does it have excellent smelting quality, but it also has a proven track record of success in drawing dies for ferrous materials.
Wear-Resistant Steel 6077 is an electroslag steel with few and small impurities. The smaller the impurities, the better the mirror-like finish of the die steel—a property essential for drawing dies. Furthermore, 6077, which undergoes six-sided forging with a “three-forge, three-draw” process, features excellent microstructural uniformity and minimal microscopic cracks, making it less prone to sticking and wire drawing when used in drawing dies. With a hardness of 60–63 HRC, its wear resistance is guaranteed; its resistance to spalling is three times that of chromium steel, ensuring the die will not crack.
Mr. Tan said that the 6077 wear-resistant steel he bought last time worked quite well. I used it to deep-draw 0.7mm galvanized sheet metal into motor housings with a drawing height of 30mm, and have already produced 3 million units without a single customer complaint. In the past, when I used DC53 for drawing dies, they would start showing wire marks after producing only a few products, and I’d get scolded by customers. Now that I’m using 6077 wear-resistant steel, the dies can produce a total of 3 million products, and they don’t even need a coating—I’m completely satisfied. As a die manufacturer, I’m happy as long as there are no customer complaints.
Yuhui Wear-Resistant Steel 6077—in terms of smelting quality, microstructure, and performance—fully meets the three key requirements for steel drawing dies: high hardness, adequate toughness, and resistance to material adhesion. Moreover, it is reasonably priced, ensuring a long mold life and offering excellent overall value for money. It resolves the issue of drawing marks commonly associated with the use of Cr12MoV, SKD11, and DC53 in iron drawing dies, making it the top choice for such applications. Furthermore, since no coating is required, you’ll avoid a lot of hassle and save a significant amount on coating costs.
The heat treatment for Wear-Resistant Steel 6077 involves high-temperature tempering in a dedicated furnace, with a tempering temperature far exceeding the 450°C required for PVD coating. Even if you do decide to apply a surface coating, the results will be achieved with half the effort.
The user who asked about the 1-thick cold-rolled sheet experiencing persistent stretching marks should definitely give Wear-Resistant Steel 6077 a try.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.