Heat treatment of JIS G3462 STBA23 Alloy boiler and heat exchanger tubes
| Designation of grade | Heat treatment a) |
| STBA23 | Isothermal annealing, full annealing or normalizing followed by tempering b) |
Notes : Low temperature annealing shall not be applied to the electric resistance welded steel tube.
The tempering temperature for JIS G3462 STBA22 Alloy steel tubes shall be 650°C or higher.
Chemical Composition of JIS G3462 STBA23
| Standard:JIS G3462 | Grade | Chemical Composition Limits (%) | ||||||
| C | Si | Mn | P | S | Cr | Mo | ||
| STBA23 | ≤ 0.15 | 0.50-1.00 | 0.30-0.60 | ≤ 0.030 | ≤ 0.030 | 1.00-1.50 | 0.45-0.65 | |
Mechanical Properties of JIS G3462 STBA23
| Designa tion of grade |
Tensile strength a) N/mm 2 |
Yield point or proof stress N/mm 2 |
Elongation % | ||||
| Outside diameter | |||||||
| Under 10 mm | 10 mm or over to and excl. 20 mm | 20 mm or over | All diameters | ||||
| Tensile test piece | |||||||
| No. 11 test piece | No. 11 test piece | No. 11 test piece or No.12 test piece | No.4 test piece | No.14A test piece | |||
| Tensile test direction | |||||||
| Pararell to tube axis | Pararell to tube axis | Pararell to tube axis | Pararell to tube axis | Pararell to tube axis | |||
| STBA23 | 410 min. | 205 min. | 22 min. | 25 min. | 30 min. | 24 min. | 21 min. |
