Study Of Microstructures And Mechanic Properties Of Novel High Alloy Cast Irons With Wear Resistance And Corrosion Resistance

Concrete lines produced by conventional process are of low toughness and wearresistance, leading to short service life. The paper aims to figure out this problem by designing a material with novel component and through inoculation and heat treatment. The microstructures and properties were investigated by OM, SEM, TEM, XRD, and HR-150 A hard meter, JB294/147 A impact tester. The erosive wear tests were conducted in MCF-30 tester.The results show that the casting structures were composed of Sorbite, martensite, residual austenite and eutectic carbides with and without inoculation treatment. After composite inoculation treatment, the matrix structures transformed from columnar dendrites into tiny equiaxed dendrites, the carbides became more smaller, and carbide network appeared necking phenomenon, the hardness and impact toughness were simultaneously increased.The heat treated structures were composed of tempered martensite, a small amount of residual austenite, and carbide with or without inoculation treatment. After heat treatment the structures further refined, the columnar dendrites and long flake carbides disappeared, and the matrix was transformed into equiaxed grain, the carbide distribution improved obviously, and transformed from short rod into small chrysanthemum shape. The hardness increased tremendously through heat treatment. Heat treat project A is optimum owing to its promotion of impact toughness.The mechanical properties were improved by combination of inoculation and heat treatment. The hardness increased by 21.4%, from HRC52.7of as cast alloy without inoculation treatment to HRC64.0 of alloy which treated by project A with inoculation treatment; and the impact toughness is increased by 43.3%, from 3.0 J/cm2 to 4.3J/cm2.In the erosive wear test, with the increase of rotational speed, erosive wear morphology was deteriorating, the crack appears when the speed increased to 400 r/min, the wear volume and rate were increased with the promotion of rotational speed. Alloy which treated by project A with inoculation treatment showed up the optimum erosive wear resistance.Through component design, inoculation and heat treatment, the carbide morphology of concrete lines was improved, the mechanical properties and erosion wear resistance were increased, make it more stable and longer service life.