热处理对ZCPC-BTMCr20高铬铸铁微观组织和硬度的影响

Effect of heat treatment on microstructure and hardness of ZCPC-BTMCr20 high chromium cast iron

某厂生产的破碎矿石用锤头,其服役寿命较低,仅20 h左右就因为磨损严重而失效。研究了不同热处理工艺对其组织硬度的影响。结果表明:锤头试样成分接近ZCPC-BTMCr20高铬铸铁,基体为较软的珠光体组织,宏观洛氏硬度仅为41.1 HRC,达不到相关标准要求。经960、985、1010℃加热保温,通过控制冷却速度可以得到马氏体或奥氏体基体,基体硬度提高,宏观硬度大于58 HRC。综合分析对于ZCPC-BTMCr20高铬铸铁,建议采用960℃空淬+450℃回火的热处理制度,其洛氏硬度可达60.1 HRC。

A hammerhead for crushing ore produced by factory had a relatively low service life,and it fails due to severe wear only in about 20 h.The influences of different heat treatment processes on hardness and microstructure of the hammerhead were studied.The results show that the composition of the hammerhead specimen is close to that of the ZCPC-BTMCr20 high chromium cast iron,the matrix is a softer pearlite structure,and the macroscopic Rockwell hardness is only 41.1 HRC,which does not meet the requirements of relevant standards.After heating and holding at 960℃,985℃,1010℃ respectively,martensite or austenite matrix can be obtained by controlling the cooling rate,and the hardness of the matrix is improved,with the macroscopic hardness greater than 58 HRC.Based on comprehensive analysis for ZCPC-BTMCr20 high chromium cast iron,it is recommended to adopt a heat treatment system of 960℃ air quenching +450℃ tempering,so the Rockwell hardness can reach 60.1 HRC.