Simulation Of TA2 Titanium Plate Butt Welding And Its Properties

Due to the poor working environment,the equipment of crude oil constant roof oil-gas heat exchanger often fails during operation.In order to improve the service performance of the equipment,it is decided to use industrial pure titanium TA2 where the equipment often fails.In this paper,the distribution law of temperature field and stress field of different welding currents is analyzed by numerical simulation,and the optimal current value is obtained.On this basis,the distribution law of temperature field and stress field of welded joints of different welding materials is analyzed,and the protective towing cover is designed according to numerical simulation to improve the accuracy of welding test,Combined with the post weld test,the changes of microstructure,mechanical properties and corrosion resistance of the welded joint are analyzed,and the conclusion is drawn.Through the SYSWELD finite element software,the temperature field and stress field of different welding currents are analyzed.It is concluded that with the increase of welding current,the heat input increases,the width of heat affected zone increases,the residual stress of welded joint increases,the welding current is too large,the width of heat affected zone increases obviously,the welding current is small,and the weld stress concentration is obvious,Finally,the welding current of 180 A is determined to be the best.The numerical simulation results of different welding materials show that when the welding current is 180 A,the peak temperature of TA1 welding material is higher than TA2 welding material,the width of heat affected zone is greater than TA2 welding material,the residual stress value is higher than TA2 welding material,and the uniformity of residual stress along the weld direction is better than TA2 welding material.The results of post weld inspection show that there are no cracks in the welded joints of bending test;The tensile test shows that the mechanical properties of TA2 welding material are the best.The microstructure observation shows that with the increase of welding current,the content of acicular martensite in weld increases and the width of heat affected zone increases.When the current is 200 A,the acicular martensite in weld changes to strip shape and the width of heat affected zone increases obviously;Under different welding materials,the distribution of acicular martensite in the weld of TA2 welding material is closer and the heat affected zone is narrower,indicating that the more acicular martensite in the weld and the narrower the width of the heat affected zone,the better the mechanical properties of the welded joint.The corrosion resistance of the four groups of welded joints is also different.Under different welding currents,the welding current of 180 A has the best corrosion resistance.Among different welding materials,the corrosion resistance of TA1 welding material is better than that of TA2 welding material.