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TP304H austenitic stainless steel
Source:Xinsteel   Date:2020-04-12
TP304H is austenitic stainless heat-strength steel, with good bending pipe, welding process performance, high endurance strength, good corrosion resistance and organizational stability, cold deformation ability is very high. Steel grades equivalent to TP304H include China's 1Crl9Ni9, OCrl9Ni9, American TP304, Japanese SUS304, SUS304TP, etc.
Production Process
   (1) Heat processing: the initial forging temperature is 1130∽1180 ℃, the final forging temperature is ≥850 ℃, and the air is cooled after forging. Due to the poor thermal conductivity of austenitic steel, it should be heated evenly, and a larger reduction and a higher final forging temperature should be used.
(2) Cold processing: excellent cold deformation ability and deep drawing performance. Because the cold work hardening ability of steel is very strong, when the amount of deformation in the cold working process is large, it is recommended to insert an intermediate solution heat treatment. For the boiler steel tube, after cold forming, a solution treatment of 1066 ± 28-C and at least 30 minutes of heat preservation should be carried out.
(3) Heat treatment: use in solid solution. All oil film, grease and other compounds should be removed before heat treatment and furnace installation to prevent carbon increase. My country's GB 5310-1985 standard stipulates the solution treatment temperature for boiler steel pipes to be ≥1040 ℃; GB 13296-1991, GB 1220-1984, GB 1221-1984 standard stipulates the solution treatment temperature to 1010∽1150 ℃; The temperature of solution treatment of cold drawn boiler steel pipe specified by Industrial Steel Pipe Manufacturing Co., Ltd. is 1120∽1165 ℃, at least 2∽6min of heat preservation, water cooling; American Combustion Engineering Company stipulates that cold drawn steel pipe for boiler should be 1066 ± 14 ℃ for 15∽30min of solution treatment. After all welding and forming processes are completed, 1066 ± 28 ℃ for at least 15min of solution treatment should be carried out.
(4) Welding: The welding performance of this steel is very good, you can use various methods such as automatic hydrogen arc welding (GTAA), molten electrode gas shielded welding (GMAA), manual hydrogen arc welding (GTA) and manual arc welding (SMA) For welding, manual welding can use Austrian 102, Austrian 107, Austrian 137 or American grade E308-15 electrode; ammonia arc welding wire uses HOCrl9Ni9. Solution treatment after welding can improve the thermal strength and resistance to intergranular corrosion of the joint.
Uses: TP304H and its equivalent steel can be used for the superheater tube and superheater tube of ultra-supercritical boiler, and the wall temperature of the reheater tube is allowed to be ≤650 ℃.