2) Low hardness required mold (HRC54-57) This kind of mold is often thicker in punching material (3-8mm. Its process is divided into two types: one is normal process quenching, high temperature tempering, tempering temperature and hardness are corresponding details as following: Previous page Furniture Handle,Minimalist Glass Door Handle,Copper Black Circular Handle,Zinc Alloy Modern Handle Zhaoqing Muyi Hardware Products Co., Ltd , https://www.mywjhandle.com
430 ° C tempered 57-58HRC
Tempering at 480 ° C 56 ± 0.5HRC
520 ° C tempering 54-55HRC
600 ° C tempered 53-54HRC
After tempering at a higher temperature, it can be tempered again because of the high toughness of the mold. Although a small amount of retained austenite can be converted to martensite after tempering, it can be safely used.
Another method is to use sub-temperature quenching, the process is as follows:
880 ° C heating quenching 53-54HRC
900 ° C heating quenching 56-57HRC
920 ° C heating quenching 58-59HRC
However, tempering must use 220 ° C nitrate salt tempering, can be tempered once, quenching method can obviously save energy, tempering is not due to special configuration of furnace temperature.
3) High-speed steel punch and push rod (usually 6542 or SKH9)
The hardness is HRC58-62, it does not require high hardness, because the high-speed steel is about 30% higher than Crl2MoV under the same hardness, but the material price is about 60-80 yuan/kg, and the Crl2MoV price is 16 yuan/kg. It can be tempered twice at 220 ° C or 430 ° C by quenching at 1080 ° C or 1180 ° C. (such as Forestry Tools Factory, Zhenhua Mould Factory)
The other is special materials such as high-speed punching or punching paper (300-800 beats per minute)
Hardness requirement HRC63-65
It must be heated and tempered three times in normal process (such as Jingren Electronics, Japan ALPS, Taiwan Yongan Precision Machinery, Central Asia Mould)