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本文用Y型坡口拘束抗裂试验等方法,评定了Mn-Mo-Nb型压力容器用低合金高强钢消除应力(SR)裂纹的敏感性,并使用扫描电镜、X 光结构分析、α粒子径迹照相等综合测试技术,研究了微量硼对Mn-Mo-Nb 钢SR 裂纹敏感性的影响。文中指出,微量硼明显地提高Mn-Mo-Nb 型钢SR 裂纹敏感性,其影响程度主要取决于碳硼化物在焊接热影响区粗晶晶界的析出形态和集聚行为,以及由此而引起的热影响区粗晶区高温蠕变延性的降低程度。该结论被含硼钢SR 裂纹的独特形貌所证实。本文在探讨微最硼对Mo-Mn-Nb 钢SR 裂纹形成机制的基础上,提出了控制“硼相”和防止SR 裂纹产生的措施。
In this paper, Y-groove restrained crack test and other methods to evaluate the Mn-Mo-Nb pressure vessel low alloy high strength steel to eliminate stress (SR) crack sensitivity and scanning electron microscopy, X-ray structural analysis, α particles Track photography and other comprehensive testing techniques to study the impact of trace boron on SR crack susceptibility of Mn-Mo-Nb steel. It is pointed out that the trace amount of boron obviously improves SR crack sensitivity of Mn-Mo-Nb steel, and the degree of influence depends mainly on the precipitation morphology and agglomeration behavior of carbides in the coarse grain boundaries in the HAZ, and the consequent The extent of high temperature creep ductility in the heat affected zone. This conclusion is confirmed by the unique morphology of SR crack in boron-containing steel. In this paper, based on the discussion of micro-boron on the formation mechanism of SR crack in Mo-Mn-Nb steel, the measures to control the “boron phase” and prevent SR crack are put forward.