CAJ | 학술논문

针对以Q450NQR1钢(中梁)为基板、B级钢(上心盘)为腹板模拟实际工装位置,疲劳断裂与货车运营实际工况不符的问题,提出以B级钢为基板、Q450NQR1钢为腹板进行三点弯曲疲劳试验,诱使疲劳裂纹向B级钢侧扩展,研究了MAG气体保护焊B级钢/Q450NQR1钢搭接接头的疲劳性能.结果表明:B级钢/Q450NQR1钢搭接接头的疲劳裂纹多出现在B级钢侧,与货车运营的实际工况相符.在循环次数2x106、存活率95%、置信水平90%时,搭接接头焊态、打磨态、喷丸态的疲劳强度分别为201.89、225.36、232.69MPa;表面机械打磨、喷丸工艺能够较好改善B级钢/Q450NQRI钢搭接接头的疲劳性能.
침대이Q450NQR1강(중량)위기판、B급강(상심반)위복판모의실제공장위치,피로단렬여화차운영실제공황불부적문제,제출이B급강위기판、Q450NQR1강위복판진행삼점만곡피로시험,유사피로렬문향B급강측확전,연구료MAG기체보호한B급강/Q450NQR1강탑접접두적피로성능.결과표명:B급강/Q450NQR1강탑접접두적피로렬문다출현재B급강측,여화차운영적실제공황상부.재순배차수2x106、존활솔95%、치신수평90%시,탑접접두한태、타마태、분환태적피로강도분별위201.89、225.36、232.69MPa;표면궤계타마、분환공예능구교호개선B급강/Q450NQRI강탑접접두적피로성능.
The result of the fatigue frature was different from the actual work condition in the simulation of the factual tooling position under the condition that Q450NQRl steel was used as base plate,B-grade steel(top center plate)was used as web plate.To solve the problem,a three-point bending test was put forward.The fatigue cracks spreaded laterally and the fatigue properties of the lap welded joints of B-grade steel/Q450NQR1 were investigated.The test result shows that the fatigue cracks of the improved sample mostly occurrs on the side of B-grade steel that is corresponding to the situation of the actual work condition of the freight train.The fatigue strength of original butt joints,blasting shot joint,sanding joint are 201.89 MPa,225.36 MPa,232.69 MPa,respectively under the condition that cycle index is 2 x106fraction surviving is 95%,confidence is 90%.The fatigue properties of the lap welded joints of the B-grade steel/Q450NQR1 greatly improve through treating surface with mechanically polishing and blasting shot.