Study Of Re Compound Modification Treatment On The High Chromium Cast Iron

This article studies the effects of RE, RE-Mg, RE-Al and RE-B-V-Ti on structure, toughness, hardness, and wear resistance of high chromium cast iron by contrast experiments. Analysis methods such as scanning electron microscope (SEM), digital metallographic microscope, hammer impact machine, hardness measure apparatus,wear and tear testing machine are used to investigate the mechanic performance of high chromium cast iron by modification. The results show that RE, RE-Mg, RE-Al and RE-B-V-Ti can improve the structure, toughness, hardness, and wear resistance of high chromium cast iron. The structure of high chromium cast iron is fine when RE is inputted. Carbide changes from net to fracture net and nubbin form. The effect of modification treatment is obvious when quality fraction of adding RE is 0.6%. The size of grain is larger and the carbide distributes large net and thick lath in cast structure of high chromium cast iron without modification; adopting RE-Mg can break the carbide net and make carbide thinner. Dissevering action of basement becomes smaller and continuity of basement becomes stronger. The comprehensive performance of the material is the best when quality fraction of adding RE-Mg is 1.5%. The amount of residual austenite obviously reduces and the size of austenite greatly fine after modification. Carbide changes from thick lath form to fine lath form and chrysanthemum form; the comprehensive performance of the material is the best when the optimum quality fraction of adding Al is 0.3% and that of adding RE is 0.4%. Modification treatment of RE-B-V-Ti can decrease the content of residual austenite in the structure of high chromium cast iron, the carbide change thick net to fracture net, long strip, board and isolated nubbin. Through the comprehensive analysis of the modification effects of RE, RE-Mg, RE-Al and RE-B-V-Ti, results show that improvement of the structure, hardness, impact toughness, wear resistance of the high chromium cast iron is the best obvious; when the quality fraction of adding RE-B-V-Ti is 1%, 0.5%, 1%, 1% respectively, the comprehensive performance of the material is the best and the hardness can reach the maximum-62.2HRC; impact toughness of cast state and heat treatment state can reach 8×104J/m2 and 9×104J/m2 respectively.