Good customers are reasonable. Yuhui’s PM23 punch extended the service life by 1.5 times, which made Mr. Liang very happy.
Mr. Liang was punching two 5.2mm holes and one 6.8mm hole in 3.7mm-thick stainless steel, all of which were pilot holes for tapping. The dimensional tolerances were strict. With standard PM23 punches plus coating, the punches would wear out and the coating would peel off after 5,000 to 8,000 punches.
These operating conditions are quite harsh. Mr. Liang was aware of this when designing the die; given the thickness of the stainless steel, he would have been satisfied if the punch could simply handle mass production. However, the PM23 punches with coating purchased from the punch manufacturer began losing their coating after just 5,000 strokes, and by 8,000 strokes, the punches were scrapped. They couldn’t even last a single day’s production run. Once the punches wore out, they had to be replaced, requiring mid-production shutdowns to swap them out, which is quite troublesome and very time-consuming.
Mr. Liang has purchased our die steel before and knows that our die steel is of high quality with guaranteed performance. Last time, he commissioned our company to procure PM23 powdered high-speed steel to wire-cut the punches. Although the machining process is a bit more complicated, it’s worth it as long as the punches perform well.
Mr. Liang told me today that by using Yuhui PM23 for his punches, he can now achieve 12,000 strokes—a 1.5-fold increase in punch life. I can run the press all day without needing to replace the punches, which I’m satisfied with and find acceptable. I was just wondering if you could help me see if there’s any room for further improvement.
When using die steel of the same grade to stamp the same product, service life increases by 50%, which is attributable to the quality of the smelting process. PM23 is a high-carbon, high-alloy high-speed steel produced using advanced powder metallurgy techniques, with a carbon (C) content of 1.3%, tungsten (W) content of 6.5%, and vanadium (V) content of 3.0%; it features a favorable carbide structure. However, if the smelting quality is poor and the microstructure exhibits segregation, microcracks will form, leading to adhesive wear caused by material sticking. Uneven carbide distribution will also affect wear resistance. The fact that the coating begins to peel off after 5,000 stamping cycles and the punch becomes unusable after 8,000 cycles—with powder debris adhering to the punch—further corroborates this point.
In contrast, high-quality PM23 produced through superior smelting processes exhibits no microstructural segregation. The resulting carbides are fine and uniformly dispersed, which not only enhances wear resistance but also improves strength and fracture resistance. Yuhui PM23 has now increased punch life by 50%, further corroborating this point.
What pleased me even more was when Mr. Liang said, “We all know that General Wu’s mold steel is of excellent quality. Although it’s a bit more expensive, its performance is absolutely guaranteed. It has never disappointed us, so I’ll use your mold steel for all my needs.”
Good customers are reasonable; they don’t haggle over price, but they do value reason.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.