The Study Of Welding Technics Of Boiler Metal Material In Numerical Simulation Way

The demand on the power is rising fleetly with the development of Chinese economy, super criteria and up- super criteria power station have been the first selection as increasing the efficiency of function, decreasing the costing and reducing pollution. As the representation of these kinds of steel, T/P91 of new grade boiler steel and TP347H of stainless steel have been developed and applied. The same characteristics of the new grade and stainless steel are the increasing of high temperature strength and stainless, and excellent parameter ability. But still there are some welding problems.In this paper through the entrance of FORTRAN subroutine in Msc.Marc, the model of T/P91 steel under TIG welding is built and it is accordant with practice. The width of 800/1000℃ (can not be gotten in practice) and stress field of welding joint are stimulated and the relation of type IV cracking to welding parameter is studied, some results are come out: decreasing line energy will decrease the width of 800/1000℃ and stress of welding joint and there is a good match in welding current, voltage and speed; the width of 800/1000℃ can be decreased obviously in decreasing line energy through increasing current and increasing speed, so the incline of type IV cracking can be decreased.Based on the similar criterion of exponential analysis and equation analysis and Gauss heat flux, the model of TIG welding temperature field was established, and it is accordant with practice; in the stimulation of residual stress fields and residual displacement field of the welded joints in the dissimilar steels of T23 and T/P91, Y residual stress of high match is low and residual displacement field also is even, Y residual stress of low match is high and residual displacement field has a peak value in the welding joint, but from operation technics, T/P23 is excellent in operation technics, low match is easy to operate and get a high quality welding joint; in the simulation of residual stress fields and residual displacement field of welded joints in the dissimilar steels TP347H and T/P91, the residual stress fields of low match is low and residual displacement field also is even, Y residual stress field and residual displacement field of high match is the highest, Y residual stress field and residual displacement field of nickel match is between low and high match, but from metallurgy, nickel match is best right.Still welding parameter of electrode of thick aluminum plate and Dissimilar electrode of copper and iron are made excellent through stimulation and are verified and corrected in test or experience. Some results are found: though using A-C TIG welding, the perfect welding joint of aluminum electrode of 20mm thick can be gotten; when welding, the current and voltage should be high a little bit; for controlling gas pore, the welding speed is not too fast;...