T91 in post-weld heat treatment before cooling temperature is not lower than 100 ℃, if cooled at room temperature, but when the environment and more humid, prone to stress corrosion cracking. In Germany: Before post weld heat treatment must be cooled to below 150 ℃. In the thicker workpiece, and the presence of fillet has geometry bad circumstances, the cooling temperature is not lower than 100 ℃. If cooling at room temperature, non-humid import t91 alloy tube, or prone to stress corrosion cracking and asked the welding T91 cooled to below the Ms point and maintain a certain time to be tempered Shanghai t91 alloy tube, cooling after welding speed of 80 ~ 100 ℃ / h. If without insulation, austenite joints may not be completely transformed, tempering heating will lead along the austenite grain boundary carbide precipitation t91, this organization is very brittle. But after welding T91 does not allow to cool to room temperature and then tempered, because of its welded joints have cooled dangerous cold cracking when the room temperature. For t91 T91 alloy for optimal starting temperature of 100 ~ 150 ℃, and the insulation 1h, can basically ensure organizational change is completed. t91 alloy tube 42x5, Dandong t91, Katherine source of steel provided by 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!