Experimental Research On Welding Residual Stress Testing Of Large-scale Slider-shoe Mill

The residual stress produced by welding is an important factor that has an influence on the intensity and performance of welding strcture. There are many factors which affect welding residual stress. Moreover, the complexity of welding process and diversity of welding structure bring much trouble for the residual stress research of welding structure. However, in order to guatantee the reliability of the welding structure, knowing the size and distribution rule of residual stress are the important topic which is urgent needs to solve.At present, we haven't seen the related reports about residual stress tests of mill welded joint. This dissertation uses blind-hole method to have a test and anlysis of residual stress based on the welding process parameters. The size and distribution of it have been acquired, then the results can be used to instruct production and optimization of welding process. Therefore, the research work of this dissertation is about residual stress test and analysis, and the main results are as follows:(1)This dissertation narrates forming mechanism of welding residual stress from three aspects, such as residual plastic strain and the hot contraction strain, based on the certain experimental quantity and the supposition of certain distribution function, then takes an introduction of related theory about residual stress. The above work can help to understand the forming reasons of residual stress, and ultimately lays a theory foundation for the test of welding residual stress;(2) This dissertation introduces residual stress test methods, uses blind-hole method combined with engineering characters and facts, then carries on detailed introduction of its test principle and process to prepare for welding residual stress test;(3)For the sake of knowing the size and distribution of residual stress of mill welded joints, this dissertation separately manufactures a T shape weld joint and butt joint selecting raw material of mill, the size of test plates is same to tube body and slider-shoe thickness. Then uses blind-hole method to experiment on the T shape weld joint and butt joint based on the actual welding process.At last, the size of residual stress on the surface of welded sim and its near region of the experimental models in the condition of non-annealing and annealing has been acquired;(4) This dissertation finally carries spot test on the surface of welded sim and its near region of mill produced by CBMI CONSTRUCTION CO., LTD. The size and distribution rule of residual stress is obtained through the contrast of same test position in the condition of non-annealing and annealing, and this provides a base for the practice and summarization of residual stress distribution rule.