Effect Of The Geometry Of Under Matched Butt Join On The Bending Performance

High strength steel welding with undermatched can improve the toughness, reduce cold cracking, and reduce the preheating temperature or no preheating welding. And welded joints by low matching geometry optimization can get the same match with the other static load capacity and fatigue.and welded joints. However, undermatched weld joins of high strength steel have low bending performance which limited its wide application. Using welding-related mechanical theory combined with finite element numerical simulation, this paper presentes the method of improving the bending performance of under-matched welded joints by geometric optimiztion. And verify the results by bending test. The results show that optimizing the details of the joins size of under-matched welded joints can improve the bending performance, so the match ratio can be chosen in a wide range.By the large engineering software MSC.MARC, through finite element calculating to study the geometric parameters'impact on the bending performance and design the under-matched welded butt joints of high-strength steel. Discuss the the rheological behavior of metals and cracking tendency of conventional equal-matched level butt joints,common undermatched butt joints and optimizated undermatched butt joints. The optimizated under-matched joints'bend angles are significantly higher than the common under-matched butt joints. The optimizated joins will crack at the base metal'geometric mutations arrounding the weld fusion line and the common butt joints will crack at the surface of the weld joints.Carrying out the bending test, comparing and analysising the bending performance of optimized joints with common under-matched butt joints and equal-matched butt joints, the results show that the optimizated under-matched joints'bending performance are significantly superior to the under-matched joints with natural shape, also slightly better than the conventional equal-matched joints. The experimental results show the accuracy of the finite element method and optimization of the feasibility joints.For the butt joints with match ratio is 0.43, analyse the joint geometry parameters'influence law on the bending performance by the finite element method and obtain the optimized geometric parameters; by bending test of the optimized joints verify the correctness of the finite element method and finite element analysis optimization scheme is feasible.