Choice of Material In order to make a full use of overseas technology,we have firstly tested microstructure,mechanical properties and chemical composition of the remaining import VAI steel plates.It is shown that the material of the import plates are made from anti-abrasion high alloy,the composition of the material is listed in the first table,that is,martensite with primary and secondary carbide bars whose hardness is HRC62-64.Besides,we have studied the commonly-used wear materials abroad and the literatures concerned, together with the operating theory of impact crushers and the research of large quantities of materials in China,we finally choose CYK high-chromium alloy cast iron as our material for the wear liners