X80钢低温焊接接头组织与性能研究

Study on Microstructure and Properties of Welded Joint of X80 Steel at Low Temperature

为了研究X80管线钢在低温环境下焊接的接头性能,本文对X80钢采用焊条电弧焊模拟不同温度条件进行焊接,并对获得的焊接接头进行拉伸试验、冲击试验、硬度测试及金相观察,利用SEM观察焊接接头断口形貌。结果表明:X80钢在低温环境下焊接接头的拉伸强度、冲击韧性等力学性能都较常温环境下低,而硬度值有所上升;随着焊接温度的降低,X80钢焊接接头的断裂方式由韧性断裂逐渐转变为脆性断裂。

In order to research X80 pipeline steel welded joint under the condition of low temperature performance, X80 steel was welded at different temperature conditions by shielded metal arc welding. The tensile test, impact test and hardness test of the welded joints were carried out. The fracture morphology of the welded joint was observed by SEM. The results show that at low temperature environment, the tensile strength and impact toughness of the welded joint are lower compared with normal temperature environment and the hardness increases. With the reduction of welding temperature, the fracture mode of X80 steel welded joint gradually transforms from ductile fracture into brittle fracture.