预制层中合金粉末粒度对WC/钢基表层复合材料复合效果的影响

Effect of Alloy Powder Granularity in Preformed Layer on Complex Performance of WC/Steel Surface Composites

在以高铬钢为基材,WC颗粒为增强颗粒,使用不同合金粉末粒度的预制层的条件下,利用真空实型铸渗法制备了WC/钢基表层复合材料,重点研究了预制层中的合金粉末粒度对表层复合材料铸渗过程及复合效果的影响。采用XRD、SEM对表层复合材料的组织进行了研究。结果表明：随着高碳铬铁粉末粒度的减小,WC颗粒在基体中的熔解程度增大,铸渗层的厚度增加,过渡层变化平缓,表面质量也日趋完好,当粉末粒度为200~320目时,所制备出的表层复合材料铸渗层完整,无裂纹,铸渗层的厚度为3mm。经分析可知,金属液带来的热量与浇铸后高温状态保持的时间长短对复合效果起到了关键性的作用。

Using the high-chromium steel as substrate, WC as reinforced particles and preformed layer with different alloy powder granularities, the steel-based surface composites were fabricated by Vacuum-Evaporative Pattern Casting （V-EPC） and the study was concentrated on effect of alloy powder granularity on the composites and infiltration casting process. The microstructures of the composites were studied by XRD and SEM. Results show that with decrease of alloy powder granularity, the meltage of WC particles increases, the infiltration layer becomes thicker, transition layer is smooth, and the quality of surface becomes better. When the granularity of high carbon-Cr iron powder is 200 to 320 meshes, the WC/steel surface Composites has intact and flawless infiltration layer, which is 3 mm thick. As a result, two key factors determining the performance of the composites are respectively the heat quantity of molten steel and the holding time of high temperature after casting.