JIS G3458-alloy steel boiler pipes
JIS G3458 Standard is made for heat resistant alloy steel pipes that are used for high temperature conveying fluid pipes for heaters and boiler tubes.
Manufacture Method:
| Grade | Heat treatment |
|---|---|
| STPA 12 | Low temperature annealing isothermal annealing, full annealing, normalizing full annealing, normalizing or normalizing followed by tempering |
| STPA 20 | |
| STPA 22 | |
| Low temperature nnealing, isothermal annealing, full annealing or followed tempering | |
| STPA 23 | |
| STPA 24 | |
| Isothermal annealing, full annealing or normalizing followed by tempering | |
| STPA 25 | |
| STPA 26 |
Chemical Composition:
| Grade | Chemical Composition % | ||||||
|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | Cr | Mo | |
| STPA 12 | 0.10~0.20 | 0.10~0.50 | 0.30~0.80 | 0.035 max. | 0.035 max. | - | 0.45~0.65 |
| STPA 20 | 0.10~0.20 | 0.10~0.50 | 0.30~0.60 | 0.035 max. | 0.035 max. | 0.50~0.80 | 0.45~0.65 |
| STPA 22 | 0.15max. | 0.50 max. | 0.30~0.60 | 0.035 max. | 0.035 max. | 0.80~1.25 | 0.45~0.65 |
| STPA 23 | 0.15max. | 0.50~1.00 | 0.30~0.60 | 0.030 max. | 0.030 max. | 1.00~1.50 | 0.45~0.65 |
| STPA 24 | 0.15max. | 0.50 max. | 0.30~0.60 | 0.030 max. | 0.030 max. | 1.90~2.60 | 0.87~1.13 |
| STPA 25 | 0.15max. | 0.50 max. | 0.30~0.60 | 0.030 max. | 0.030 max. | 4.00~6.00 | 0.45~0.65 |
| STPA 26 | 0.15max. | 0.25~1.00 | 0.30~0.60 | 0.030 max. | 0.030 max. | 8.00~10.00 | 0.90~1.10 |
Mechanical Properties:
| Grade | Mechanical Properties | |||||
|---|---|---|---|---|---|---|
| Tensile strength | Yield point or proof stress | Elongation % | ||||
| kgf/mm2 {N/mm2} | kgf/mm2 {N/mm2} | No. 11 or No.12 test piece | No. 5 test piece | No.4 test piece | ||
| Longitudinal | Transverse | Longitudinal | Transverse | |||
| STPA 12 | 39{382}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
| STPA 20 | 42{412}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
| STPA 22 | 42{412}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
| STPA 23 | 42{412}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
| STPA 24 | 42{412}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
| STPA 25 | 42{412}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
| STPA 26 | 42{412}min. | 21{206} min. | 30 min. | 25 min. | 24 min. | 19 min. |
