大型SA508.Gr3低合金钢锻件夹杂物断裂行为分析

通过模拟拉伸试验，研究焊接热循环条件下大型SA508.Gr3低合金钢锻件夹杂物断裂行为，结果表明，大型SA508.Gr3低合金钢锻件在焊接热循环条件下，当锻件母材中微小冶金为近似圆形或孔洞时，母材在存在有圆形缺口的条件下，仍有较好的塑性变形能力，断后伸长率达到20%以上，高温拉伸中不易产生裂纹；锻件母材中微小冶金存在尖锐角度且夹杂物超过临界尺寸时，母材在热循环作用下会产生0.2%应变损失，在锐角处容易诱发裂纹. 在实际生产中需要对母材中超过临界尺寸的尖锐角度的缺欠应进行消缺处理.

Fracture behavior analysis of inclusions in large forgings of SA508.Gr3 low alloy steel

The fracture behavior of inclusions in large SA508.Gr3 low alloy steel forgings under welding thermal cycling was studied by simulating tensile test. The results show that the large SA508.Gr3 low alloy steel forgings with circular notches still have good plastic deformation ability under welding thermal cycling conditions, and more than 20% elongation is obtained. Cracks are not easy to occur in high temperature tension. When the micro-metallurgy in the forging base metal has sharp angle and the inclusions exceed the critical size, the base metal will have 0.2% strain loss under thermal cycling, and the cracks are easy to induce at the sharp angle area. In actual production, it is necessary to eliminate the deficiency of sharp angle exceeding critical size in base metal.