不同预热温度下马氏体钢焊接性及力学性能研究

Weldability and mechanical properties of martensitic steel at different preheating temperatures

针对火箭发动机在重复利用中机架等结构焊接件的可靠性提升问题,用G232焊条焊接10Cr13Ni2马氏体钢,通过冷裂纹敏感性、拉伸、冲击试验,研究在不同工艺对钢材的焊接性及焊接接头力学性能的影响,获得最佳焊接工艺对焊接接头受力载荷的影响。结果表明:预热温度为0~250℃时,接头产生冷裂纹倾向小;预热温度由150℃升至250℃时,焊接接头抗拉强度增加,断口由韧性的韧窝-准解理断裂变为接近脆性的韧窝-准解理断裂,经610℃回火后抗拉强度下降;3种工艺对焊接接头热影响区冲击韧性影响均小。

In order to improve the reliability of structural weldments such as middle frame of rocket engine in reuse,G232 electrode was used to weld 10Cr13Ni2 martensitic steel.By conducting cold crack sensitivity tests,tensile tests,and impact tests,the effects of different process conditions on the weldability of steel and the mechanical properties of welded joints were studied,and the optimal welding process on the stress load of welded joints were obtained.The results show that when the preheating temperature is between 0‐250℃,there is little tendency for the joint to produce cold cracks.When the preheating temperature increases from 150℃to 250℃,the tensile strength of the welded joint increases,and the fracture changes from dimple‐quasi‐cleavage fracture with good toughness to dimple‐quasi‐cleavage fracture with near brittleness.After tempering at 610℃,the tensile strength decreases.The three process conditions have little effect on the impact toughness of the heat affected zone of the welded joint.