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用热模拟方法研究了中碳低合金高强度钢45CrNiMo1V的焊接半熔化区。结果表明,在半熔化区的原奥氏体晶界上富集了大量溶质元素Si、Mn,Cr、Mo、V、s和P等。晶界上存在孔洞和微裂纹,因此,晶界变得脆弱,半熔化区的韧性显著下降。本文指出原奥氏体晶界溶质元素的富集与下列因素有关:①钢中的偏析带;②固液共存条件下的扩散。
The semi - melting zone of 45CrNiMo1V for medium carbon low - alloy high strength steel was studied by means of thermal simulation. The results show that a large amount of solute elements such as Si, Mn, Cr, Mo, V, s and P are enriched in the former austenite grain boundaries in the semi-melting zone. There are holes and micro-cracks in the grain boundaries, so the grain boundaries become brittle and the toughness of the semi-melted regions drops significantly. This paper points out that the enrichment of solute elements in the original austenite grain boundaries is related to the following factors: segregation zone in steel; diffusion under solid-liquid coexistence conditions.