Stress-Relieved Annealed Tubes
When stress-relieved tubes are specified, ASTM A213 seamless steel tubes shall be given a heat treatment at 1500 to 1650 °F [815 to 900 °C] after roll straightening. Cooling from this temperature range may be either in air or by slow cooling. No mechanical straightening is permitted after the stress-relief treatment. Straightness of the tubes shall be a matter of negotiation between the purchaser and supplier.
ASME SA213 Austenitic Stainless Steels
All ASTM A213 stainless steel tubes shall be furnished in the heat-treated condition, and shall be heat treated in accordance with the requirements. Alternatively, immediately after hot forming, while the temperature of the ASTM A213 heat exchanger tubes is not less than the minimum solution treatment temperature specified, tubes may be individually quenched in water or rapidly cooled by other means (direct quenched).
Superheater Tubes Stabilizing Heat Treatment
Subsequent to the solution anneal required, Grades TP309HCb, TP310HCb, TP310HCbN, TP321, TP321H, TP347, TP347H, TP348, and TP348H shall be given a stabilization heat treatment at a temperature lower than that used for the initial solution annealing heat treatment. The temperature of stabilization heat treatment shall be at a temperature as agreed upon between the purchaser and vendor.
| Grade | UNS | Heat Treat Type | Austenitizing / Solutioning Temperature, min or range °F [°C] | Cooling Media | ASTM Grain Size No. B |
| Designation | |||||
| TP304 | S30400 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP304L | S30403 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP304H | S30409 | Solution treatment | 1900 °F [1040 °C] | water or another rapid cool | 7 |
| TP309S | S30908 | Solution treatment | 1900 °F [1040 °C] | water or another rapid cool | . . . |
| TP309H | S30909 | Solution treatment | 1900 °F [1040 °C] | water or another rapid cool | 7 |
| TP310S | S31008 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP310H | S31009 | Solution treatment | 1900 °F [1040 °C] | water or another rapid cool | 7 |
| TP316 | S31600 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP316L | S31603 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP316H | S31609 | Solution treatment | 1900 °F [1040 °C] | water or another rapid cool | 7 |
| TP317 | S31700 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP317L | S31703 | Solution treatment | 1900 °F [1040 °C]F | water or another rapid cool | . . . |
| TP321 | S32100 | Solution treatment | 1900 °F [1040 °C]F,H | water or another rapid cool | . . . |
| TP321H | S32109 | Solution treatment | cold worked:2000 [1100] | water or another rapid cool | 7 |
| hot rolled: 1925 [1050]H | |||||
| TP347 | S34700 | Solution treatment | 1900 °F [1040 °C]F,H | water or another rapid cool | . . . |
| TP347H | S34709 | Solution treatment | cold worked:2000 [1100] | water or another rapid cool | 7 |
| hot rolled: 1925 [1050]H |
ASTM A213 Heat Treatment notes:
F: Quenched in water or rapidly cooled by other means, at a rate sufficient to prevent re-precipitation of carbides, as demonstrable by the capability of tubes, heat treated by either separate solution annealing. Note that Practices A262 requires the test to be performed on sensitized specimens in the low-carbon and stabilized types and on specimens representative of the as-shipped condition for other types. In the case of low-carbon types containing 3 % or more molybdenum, the applicability of the sensitizing treatment prior to testing shall be a matter for negotiation between the seller and the purchaser.
H: A solution treating temperature above 1950 °F [1065 °C] may impair resistance to intergranular corrosion after subsequent exposure to sensitizing conditions in the indicated grades alloy steel tubes. When specified by the purchaser, a lower temperature stabilization or resolution anneal shall be used subsequent to the higher-temperature solution anneal prescribed in this table.
