China · GB
20Mo
GB/T 32970:2016 — Longitudinal submerged-arc welded steel pipe for high pressure service at high temperatures
Chemical composition
| Element | min | max | Similar | Remarks |
|---|---|---|---|---|
| C | 0.15 | 0.25 | ||
| Cr | 0.3 | |||
| Cu | 0.2 | |||
| Mn | 0.4 | 0.8 | ||
| Mo | 0.44 | 0.65 | ||
| Ni | 0.3 | |||
| P | 0.025 | |||
| S | 0.015 | |||
| Si | 0.17 | 0.37 | ||
| V | 0.08 |
Mechanical properties
| Heat treatment / condition | Yield strength | Tensile strength | Elongation | Reduction of area | Impact energy | Hardness |
|---|---|---|---|---|---|---|
| steel tubes | ≥220 | 415–665 | ≥22 | ≥40 | HB ≤201 |
High/low temperature
| Condition | Temperature ℃ | min |
|---|---|---|
| steel tubes | 500 | 150 |
| steel tubes | 450 | 160 |
| steel tubes | 400 | 169 |
| steel tubes | 350 | 177 |
| steel tubes | 300 | 182 |
| steel tubes | 250 | 187 |
| steel tubes | 200 | 199 |
Heat treatment
| Type | 3 | 4 |
|---|---|---|
| Heat-treatment process | Normalized | 890℃~950℃ |
| Heat-treatment process | 淬火+回火 | 590℃~730℃ |