Due to the different actual conditions of the solution condensation process, the carbide morphology, size and quantity of high chromium cast iron obtained after casting are uneven. It is necessary to improve the carbide morphology, size and quantity by heat treatment.
As shown in the figure, the heat-treated microstructure of high chromium cast iron before and after modification is compared by 1000 ° cx3h air extraction +450 ° cx2h tempering: figure a and figure C respectively show the heat-treated microstructure of high chromium cast iron without modifier; Figure B and figure D respectively show the heat-treated microstructure of the modified high chromium cast iron.
As shown in the figure, the metallographic structure of high chromium cast iron after heat treatment is mainly tempered martensite and massive carbides, as well as carbides with fine particle dispersion distribution and a small amount of residual austenite. The effect of modifier on the refinement of high chromium cast iron as heat treated is also very obvious. Compared with the as cast structure, after heat treatment, the carbide shape is round, fine and dispersed, and the continuity of the matrix structure is greatly improved.