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采用插销实验和扫描电镜观察方法详细研究了焊缝扩散氢含量和非金属夹杂物对10Ni5CrMoV低碳中合金高强钢焊接热影响区氢致裂纹断口微观形貌的影响。结果得出,扩散氢含量是影响氢致裂纹断口微观形貌的主要因素,在插销净截面应力300～800MPa的范围内,加载应力对延迟扩展区断口形貌无明显影响。钢中硫化物夹杂的增加使扩展区形貌从IG_(HE)向MVC_(HE)转变,而含氧化物夹杂钢则转为QC_(HE)。作者提出了一个新的适于解释氢致裂纹扩展第Ⅱ阶段断口微观形貌的竞争开裂模式,从而从氢致裂纹本质机制上圆满说明了上述实验结果。
The influence of weld hydrogen diffusion and non-metallic inclusions on the microstructures of hydrogen-induced fracture of HAZ in 10Ni5CrMoV low carbon medium-high strength steel was studied in detail by means of plug test and scanning electron microscope observation. The results show that the diffusible hydrogen content is the main factor that affects the microstructure of the fracture caused by hydrogen cracking. In the range of 300-800 MPa of net cross-section stress, the loading stress has no significant effect on the fracture morphology of the delayed propagation zone. The increase of sulfide inclusions in steel changed the morphology of the extended zone from IG HE to MVC HE, while the oxide inclusions changed to QC HE. The authors propose a new competitive cracking mode suitable for explaining the microscopic morphology of the second-order fracture of hydrogen induced crack growth, and thus illustrate the experimental results from the essential mechanism of hydrogen induced cracking.