Research On Casting Penetration Formation Technology And Impact Wear Resistance Of Cast-Infil Tration Layer On The Cast Steel

In this paper, by combining conventional sand casting with penetration technology, a wear-resistant tungsten-hi-Cr cast iron compound layer can be gained on the cast steel in order to prolong the serving life-time of train coupler according to the work conditions of train coupler. The elements of molding process of cast penetration are also discussed. The major influenceable process parameters on the quality and property of cast-penetrating composite materials are optimized. Influence rules of pouring temperature , pouring position, alloy granularity , alloy power percentage, coat thickness and cement on the quality of cast penetration are also discussed. By using SEM, EPMA and XRD, the microstructures, appearances of carbides and changes of chemical composition have been studied. The formation mechanisms of the wear-resistant composite layer are also disccused. The results showed: high temperature molten steel has infiltrated into the alloying layer and a part of alloy powder melted and molten steel diffuse each other. An excellent metallurgical combination existed between the cast-infiltration layer and the steel base. The structure of the composite-layer is similar to that of high chromium cast iron with the carbide of tungsten. The carbide particle-strengthened structures of the cast-infiltration layer are( Fe,Cr)₇C₃,Fe₃W₃C and WC mainly. The hardness of the composite layer is tested. The result showed: the hardness of the cast-infiltration layer is about HV1000, matrix is about HV200, there is a hardness grads from the composite-layer to the steel base. The impact wear resistance of the composite layer is tested and wear mechanism is analyzed. The result showed: the composite layer has the better impact wear-resistance when the volume percentage of WC particles is about 20³0% and that of Cr-Fe is about 30⁵0% in the composite layer. Compared with cast steel, impact wear resistance of the composite is greatly superior to the cast steel. So it has a good prospect.