Technical Study Of 15CrMoR Steel On Webbing Pessure Vessel

Webbing pressure vessel almost run in the temperature and pressure ,it must endure great load.So,welding line and HAZ of pressure vessel must request hign intensity,thermal stability and toughness, and are assured no crack.Pressure vessel researched in the project adopts 15CrMoR steel to weld.Therefore,to solve the problem of 15CrMoR steel welding crack and to acquire high quality welding joint with high strength, plasticity and flexibility are critical technology issue which determine the success of the overall design in developing and producing of pressure vessel and it must be settled.For 15CrMoR Refractory steel,We calculated its the welding crack susceptibility and analysed its crack mechanism and welding.Conbined to pratical production instance, We establish the target, and we made Gas Melt Arc Welding technology research as emphases.In this paper,the finite element analysis of temperature fields and stress fields in the multi-pass welding of 15CrMoR steel mid-thick plates is accomplished and three-dimensional temperature fields and stress fields are modeled based on the ANSYS.This paper analyzes how temperature fields in the different time and residual stress of the different directions.it can assist people to choose the right welding parameters in 15CrMoR steel.In the technical design of welding,wo adopt different preheating temperature ,welding current and welding velocity to weld and process X-radial test,mechanical performance test,microstructure analysis for welding line. It accords with demand of pressure vessel we research. Wo analyse its microstructure , microstructure of welding line and heat affected zone are pole type ferrite,banite and martensite.We optimized the dependable and effective welding technology after welding,We validated the dependability of welding technology by orthogonal test.Results studied are showed, When 15CrMoR steel welds in the preheating temperature 150～200℃, interbedded 200℃, welding voltage 22～26V,welding current 220～240A,welding velocity 16～18cm/min,postheating 250℃,preservation 1h, heat treatment temperature 680±10℃, heat preservation 1h,its joint strength obtains 560Mpa,impact of heat effect zone arrives at 82J.It absolutely accords with demand of pressure vesse we research in the project.We find by the research that thermal imput affects the microstructure and...