石油方钻杆窄间隙焊接接头断裂韧性

研究了40CrMnMo石油方钻杆窄间隙脉冲焊接接头动态断裂韧性(KId)的测试及计算方法.结合石油方钻杆的使用方法、管体结构尺寸与焊接特点,试验选用多次冲击三点弯曲试验方法,对方钻杆的焊接接头的断裂韧性进行测定.试验过程采用多次冲击加载方法,用显微镜测量裂纹深度,用FORTRAN语言编程计算a值及KId.结果表明,焊缝的KId为母材的96%,但熔合线的KId值仅为母材的89%,通过分析试件的断口及接头的金相组织,发现熔合线粗大的魏氏组织是导致该区KId值下降的主要原因.

Fracture toughness of square drill pipe joint by narrow gap welding

The test and calculation methods for the dynamic fracture toughness of 40CrMnMo square drill pipe joint produced by narrow gap pulsed metal arc welding were studied.Combined with the use of square drill pipe,pipe size and welding characteristics,the repeated impact 3-point bending test was used to test the fracture toughness of the square drill pipe joint.The crack depth was measured by using a microscope.and KId values were calculated with a FORTRAN program.The experimental results show that KId of the weld is 96% of that of the base material,but KId of the fusion line is only 89% of that of the base material.The analyses on the fracture surface and cross-sectional microstructure indicate that the bulky Widmanstatten structure near the fusion line is the main reason for a lower KId.