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SA-213TP347H high pressure boiler tube supply heat treatment status
Source:Xinsteel Date:2020/4/6
SA-213TP347H high pressure boiler tube heat treatment state: solution heat treatment
SA-213TP347H and other stainless steel pipes are mostly used in the heating surface of the boiler. During the production process, some austenitic stainless steel pipes were not subjected to solution heat treatment before delivery, or the solution treatment was not standardized, causing some boiler heating surface pipes to crack and leak to the boiler. Although safe operation poses a threat.
GB 5310-1995 (Seamless Steel Pipe for High Pressure Boiler) stipulates that the solid solution temperature of the hot-rolled tube of 1Cr19Ni11Nb (SA-213TP347H) steel should be ≥1050 ℃, and the solid solution temperature of the cold drawn tube should be ≥1095 ℃; -213M (seamless ferrite and austenitic alloy steel tubes for boilers, superheaters and heat exchangers) stipulates that all SA-213TP347H steel tubes must be solution treated, and the solution annealing temperature of hot rolled tubes is higher than 1065 ℃, then Will impair its subsequent resistance to intergranular corrosion under sensitized conditions.
The solution treatment is to heat the stainless steel to a prescribed temperature and then quickly cool it to fully dissolve the carbides and alloying elements into the austenite, thereby obtaining a uniform austenite structure. The residual stress generated in the manufacturing process is the main reason for the deformation of the boiler tube at high temperature and the stress corrosion cracking under the combined action of tensile stress and halogen ions. Choosing the appropriate solution treatment process can not only fully dissolve the alloy elements, Can also play a role in eliminating residual stress. For austenitic stainless steel, it must be heated at least at 870 ℃.
