T91 weld tempering holding time of not less than 1 h, in order to ensure their organization is completely transformed into tempered martensite. In order to reduce the residual stress T91 steel welded joints, must control its cooling rate is less than 5 ℃ / min. T91 steel welding process is illustrated in Figure 3 shows. ① preheated 200 ~ 250 ℃; ② welding t91, interpass temperature 200 ~ 300 ℃; ③ After welding cooling rate of 80 ~ 100 ℃ / h; ④100 ~ 150 ℃ incubated 1 h; ⑤730 ~ 780 ℃ tempering 1 h ; ⑥ no greater than 5 ℃ / min cooling rate by T91 steel alloying principle, especially adding a small amount of niobium, vanadium and other trace elements, high-temperature strength, oxidation resistance compared with 12 Cr1MoV steel has greatly improved, but its weldability poor. Bolt tests showed Shanghai t91 alloy tube, T91 steel has greater tendency to cold cracking of Island t91 alloy tube, select Preheat 200 ~ 250 ℃, interpass temperature 200 ~ 300 ℃ import t91 alloy tube, which can effectively prevent cold cracks. T91 weld heat treatment before, must be cooled to 100 ~ 150 ℃, holding 1 h; tempering temperature 730 ~ 780 ℃, holding time of less than 1 h. Domestic t91 alloy tube steel _ Xiangtan t91_ Katherine source provided by the source Pipe Co., Ltd. Liaocheng trillion. Liaocheng Katherine source Pipe Co., Ltd. (www.lczygg.com) strong, credible, Liaocheng in Shandong steel industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving Katherine source of innovative ideas will lead pipe and you work into the brilliant, for a better future!