The bi-metal liner offers long service life of about 800 hours, which is 2 to 3 times the lifetime of common ones in severe environment.AS one of main quick-wear parts, bi-metal liner consists of internal liner,which of made of wear-resistant high chromium alloy,and external liner,which is made of high quality carbon steel.its inner hole hardness is above HRC62 after heat treating,and it can perform a good ability of corrosion resistance and abrasion resistance in poor working condition,its normal service life is more than 800 hours.