Mr. Li from Dalang, Dongguan, just came to Yuhui Mold Steel for consultation with his product. He is a hot forged SAPH440 iron material, and now the punch has cracked after 1000 hits. What kind of mold steel is used for the punch to resist hitting?
Hot forging punches need to withstand high temperatures and form high-temperature parts. Therefore, punches require high heat resistance, high thermal wear resistance, high thermal fatigue performance, and high toughness. H13 punches with poor heat resistance are prone to mold collapse and cracking, while punch heads made of die steel with too high hardness are prone to brittle cracking.
The current punch shows thermal fatigue cracking after 1000 cycles, indicating poor heat resistance, toughness, and thermal fatigue performance of the die steel.
Based on past experience, I recommend 8566 die steel with high hardness, high heat resistance, and high toughness for hot forging punches.
The heat resistance of 8566 die steel is the same as that of high-speed steel SKH51, with a hardness of HRC58-60 and toughness four times that of SKH51. 8566 die steel softens the three aspects of high heat resistance, high hardness, and high toughness perfectly, which other mold steels cannot achieve.
Mr. Du’s mold is a motor housing made of hot-rolled No. 10 steel, with a slightly deep cavity. Originally, the punch was made of HD with a hardness of 50HRC, but after thousands of passes, the rounded corners cracked and the hardness increased to 54HRC, causing the head to fall off again. Now using the 8566 punch, the total lifespan of one punch is 200000 times, and the effect is significantly improved.
The hot forging punch cracks after being punched 1000 times, which is too short a lifespan. Constantly replacing the punch makes production difficult and inefficient. The punch is scrapped quickly, and the cost of making a punch is also high. In fact, it is not cost-effective. Just like Mr. Du, the punch used to be scrapped after being punched thousands of times. Now, an 8566 punch has a total lifespan of 200000 times. Compared with 200000 times, these thousands of times not only significantly improve the effect, but also reduce the cost of the punch and improve efficiency. It is a win-win situation.
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Wu Dejian’s tool steel, the chief of staff of the user, bought everything he had used.