CrMn Hardware Tool Steel Sheet

 

CrMn steel is a commonly used grade of low-quality tool steel and steel for measuring tools. The chemical composition of this steel is the same as that of low-conformity cutting tool steel. The carbon content is as high as 0.9%~L5%, and it is added with elements such as Cr Mn that improve hardenability. Because of its high hardness (more than 56HRC) and wear resistance, high size stability and small heat treatment deformation, the size does not change during storage and use.

 

Due to the high hardness (greater than 56 HRC) and abrasion resistance, high dimensional stability and small heat treatment deformation, the size does not change during storage and use. CrMn steel is a commonly used low-grade tool steel grade, measuring steel. The chemical composition of the steel is the same as that of the low-cutting tool steel, and the element with the weight fraction of carbon up to 0.9% to L5% and the hardenability of the element is Cr Mn. 

 

The choice of quenching temperature is to reduce the wear resistance of the deformation wells, CrMn steel should take 830 ~ 850 ° C. The size of the mold is larger or the hardenability of the lower mold, may be appropriate to improve the quenching temperature; precision demanding high mold, may be appropriate to reduce the quenching temperature, from the mold to reduce the amount of deformation and internal stress.

 

Chemical Somposition:

 

  • C: 0.90%~1.05%
  • Si: ≤0.40%
  • Mn: 0.80% -1.10%
  • Cr: 0.90% ~1.20%
  • P: ≤0.030%
  • S: ≤0.030%.

 

Process specification:

 

Positive norms

Normal temperature 900~920°C, holding time: salt bath furnace: 25~30s/mm, air 70~90s/mm, air cooling, hardness 321~415HBw.

 

Spherical retreat norms

780~800°C×2~4h, 700~720°C×4~6h, cooling rate of 30°C/h, furnace cooling to 500~600°C, out of furnace air cooling. Hardness 197~241HBW.

 

Ordinary quenching and returning specifications:

  • The quenching temperature is 840~860°C, the quenching hardness is 63~66HRC, the return temperature is 130~140°C, and the return hardness is 62~65HRC.
  • The quenching temperature is 840~860°C, the quenching hardness is 63~66HRC, the return temperature is 160~180°C, and the return hardness is 60~62HRC.

 

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