消失模铸钢件表面局部合金化研究

Part-alloying on the Surface of Cast Steel by the Evaporation Pattern Process

在泡沫模表面涂覆富钒涂层 ,利用液态铸钢浇铸时的高温和液态钢水的作用 ,使涂层被烧结成合金层 ,同时 ,涂层中的钒渗入铸钢基体组织中 ,形成渗钒层。结果表明 ,该工艺可以使钒渗入到铸钢基体中达 15 0 0～2 0 0 0 μm ,烧结层和渗钒层均为α (Fe ,V)单相组织 ,基体为铁素体和珠光体 ,渗钒层显微硬度与基体硬度相当 ,当涂层粉体粒度 <4 7μm时可得到理想的合金化渗层。涂层粉体粒度越小 ,钒原子在涂层中的扩散越容易 ,渗钒层中钒含量越高 ,渗钒层越厚。

The coat including plenty of vanadium was painted on the surface of the evaporative pattern.The coat would be sintered as alloy layer and the vanadium atoms would infiltrate into the liquid steel and become vanadizing layer by the interreaction between the liquid steel and coat,when the liquid steel was poured into mold.The depth of vanadizing layer had been 1500～2000μm,and the microstructures of sinter layer and vanadizing layer were single-phase,α-(Fe,V).The microstructure of the core were ferrite and pearlite.The microhardness of vanadizing layer was almost equal to that of steel matrix.The ideal alloy layer could be achieved when the size of coat powders was less than 47μm.The vanadium atoms infiltrating in the coat are easier,the smaller the size of the coat powders and the depth of the vanadizing layer is thicker,the higher the content of vanadium in the vanadizing layer.