The main materials of the coal mill liner are as follows:
1. Multi-element low alloy steel
At present, 40CrMnMoSiRe alloy material is widely used. After oil quenching, the material has comprehensive properties of hardness and toughness. The hardness can reach above HRC45, and the impact toughness can reach 10J/cm2 (U-shaped notch value). The material has the advantages of low price, comprehensive and stable performance. It can be cut and welded, and it is easy to install and use, and it has been widely used. But wear resistance is average.
2. Medium chrome steel material
Medium chromium steel material is also widely used in liners. This material has two treatment methods, one is oil quenching, the hardness is above HRC45, the impact toughness can reach 10J/cm2 (U-shaped notch value), the other is air cooling Or air cooling, the hardness can reach more than 45, but higher carbon content is required, and the cooling of air cooling or air cooling is generally uneven, there is a certain difference in internal and external hardness, and the stress is also large, so there is no oil quenching process. Due to the high chromium content of chromium steel and the addition of elements such as molybdenum and nickel, the wear resistance is higher than that of low-alloy materials, with better wear resistance and longer life. But the welding and cutting performance is slightly lower than that of low alloy steel.
3. High chromium cast iron series
There are mainly three kinds of high chromium liner materials: KMTBCr15Mo, KMTBCr20, and KMTBCr26. The high chromium alloy has high wear resistance due to the M7C3 type high wear resistance carbide in the structure, and of course the cost is also high. High chromium cast iron The material has poor weldability and cutability and high brittleness. It is generally used on large-scale grinders and double-in and double-out grinders that require high wear resistance.
4. High manganese steel
Menggang series materials include Mn7 (medium manganese steel), Mn13 (high manganese steel), Mn13Cr (alloy high manganese steel), Mn26 (ultra-high manganese steel), Mn26Cr (alloy ultra-high manganese steel), etc., as well as adding Other alloys are used to improve its wear resistance. Because high manganese steel has impact hardening properties, it is generally used in conditions with greater impact. In the working condition of small multi-energy impact of coal mill, most manufacturers have eliminated it.
5. Other materials
In addition, there are other alloy materials, such as 30CrMnMoSi, 40Cr2MoRe, etc., which are similar to the above low-alloy materials and are generally less used.