The effect of post weld heat treatment and distribution of residual stress in weld repaired high chromium steel (AISI 410) components

摘要

The aim of this work is to study the effect of PostudWeld Heat Treatment on the micostructural and strengthudproperties of high chromium steel [AISI 410] components.udThis work also aims to estimate the magnitude anduddistribution of the residual stress on the above type ofudwelded components.ududIn introducing this work an extensive literatureudsurvey on the historical development and the advantagesudand disadvantages of welding process has been presented.udA review of the different technique which are used touddetermine the residual stress is also presented.ududIn this work two types of Post Weld Heat Treatmentudwere used. in the first type of heat treatment, theudspecimen was kept at 316°C for 30 min, then at 427°C forud30 min, and finally, at 546®C for 2 hrs. In the secondudtype of heat treatment the specimen was kept at 760 °Cudfor 2 hrs. Two types of specimens were used to simulateudbuild-up welding and crack repair conditions, each typeudof these specimens have different parameters (thickness,udbead length and width).ududStress relaxation technique was used to detemineudthe magnitude and distribution of the residual stressesudfor the above specimens.ududThe results show that the first type of heatudtreatment reduces the hardness in the welding zone byudabout 15% of the hardness of the as welded specimen andudimproves the tensile strength. The second type of heatudtreatment decreases the hardness in the welding zone byudabout 40% but decreases the tensile strength by aboutud10%.ududThe residual stress measurements show that there isuda tensile stress around the welded zone, and that theudgreatest value recorded is about 72 N/mm*. Theseudresidual stresses decrease as the distance from theudwelding zone increases.