CAJ | 학술논문

某混凝土泵车举升臂在使用过程中发生断裂。通过宏观观察、金相组织分析、显微硬度检测和能谱检测等方法对举升臂断裂原因进行了分析。结果表明：由于轴套与臂架的焊接部位在臂架一侧未开坡口，导致该处焊后存在间隙和严重的未焊透现象，成为裂纹源和应力集中点，大大降低了轴套与臂架的连接强度；同时由于焊接工艺参数选取不当，致使热影响区出现粗大的上贝氏体组织，大大增加了该处脆性，促使裂纹进一步扩展，最终导致举升臂在使用过程中断裂。
모혼응토빙차거승비재사용과정중발생단렬。통과굉관관찰、금상조직분석、현미경도검측화능보검측등방법대거승비단렬원인진행료분석。결과표명：유우축투여비가적한접부위재비가일측미개파구，도치해처한후존재간극화엄중적미한투현상，성위렬문원화응력집중점，대대강저료축투여비가적련접강도；동시유우한접공예삼수선취불당，치사열영향구출현조대적상패씨체조직，대대증가료해처취성，촉사렬문진일보확전，최종도치거승비재사용과정중단렬。
The lifting boom of a concrete pump truck fractured during usage. Analyzed the fracture reasons by macroscopic investigation, metallographic structure analysis, micro-structure hardness testing and energy dispersive spectrometer ( EDS) detection. The results showed that the crack source and stress concentration position due to the clearance and severe incomplete penetration arising from the absence of groove at the welding area of boom and sleeve were the major causes to greatly reduce the joint strength. In addition, the improper welding parameters leaded to the formation of bulky upper bainite structures in the heat affected zone, which increased the brittleness and promoted the propagation of cracks, eventually leading to the fracture of the lifting boom during usage.