Heat-resistant Steel T91 P91 Welding Technology

For many years,the domestic and international efforts to further improve the use of heat-resistant steel.T91/P91 steel used for temperature 600~620 ? superheater pipes,heat exchanger pipes and again pipes.The chromium content of the steel is 9%~12%.The steel has higher chemical stability and organizational stability,and has better heat resistance.However,the content of the ganghe element is high.The welding hardening tendency is large,and the welding is difficult.The main welding problem is cold crack.In this paper,the process evaluation of welding,inquiry and P91,the different welding current and welding line energy,impact,tensile,bending,hardness,metallographic,and welding line energy on welding and welding line energy on welding scanning electron microscope experiment to analyze the influence of welding current and welding line energy on welding performance.During the experiment of T91/P91 heat resistant steel by argon arc grounding.Arc electrode filling cover welding current.T91/P91 heat resistant steel welded joints has great influence.When the welding process with high welding current,with the increase of welding current,welding heat input increases,the effect of the welding thermal cycle.The weld metal and heat affected zone,grain growth,resulting in the strength and hardness of welded joints increased.While the impact toughness in the welding process,so we should strictly control the welding current,welding current in backing welding I=80~95A,filling cover and mechanical I=90~110A.Microstructure and properties of weld ideal.Welding line energy had a greater impact on the microstructure and mechanical properties of welding.Welding line energy increases to 15 KJ/cm,filling capping 22 KJ/cm,carbide precipitates in the grain boundary segregation,and the impact toughness of welded joints.Welding line energy is low,when argon arc bottoming is 10 KJ/cm,filling capping at 17.5 KJ/cm.The weld metal is typical tempered sorbite with uniform and fine grain microstructure and the mechanical properties of welded joints are excellent.Therefore,the welding process has great influence on the properties of SA213-T91 and SA335-P91 welded joints,and strictly control the welding current and welding line energy.