GB 3087 ning kimyoviy tarkibi 20-sinf
| Baho | Kimyoviy tarkibi (%) | |||||||
| C | Si | Mn | P | S | Cr | Cu | Ni | |
| 20 | 0.17-0.23 | 0.17-0.37 | 0.38-0.65 | 0.030 dan kichik yoki unga teng | 0.030 dan kichik yoki unga teng | 0.3-0.65 | 0 dan kichik yoki unga teng.25 | 0 dan kichik yoki unga teng.30 |
GB 3087 ning mexanik xususiyatlari 20-sinf
| Baho | Devor qalinligi (mm) |
Mustahkamlik chegarasi (MPa) |
Hosildorlik kuchi (MPa) |
Cho'zilish % |
| dan katta yoki teng | ||||
| 20 | ＜15 | 410-550 | 245 | 20 |
| 15 dan katta yoki teng | 225 | |||
Tashqi diametri va devor qalinligining ruxsat etilgan og'ishi
| Po'lat quvur turi | Tashqi diametri (mm) | Tolerantlik | ||
| oddiy | rivojlangan | |||
| Issiq haddelenmiş quvur | OD | 159 dan kichik yoki teng | ±10%(min±0,50mm) | ±{0}},75%(min±0,40mm) |
| ＞159 | ±1.0% | ±0.90% | ||
| WT | 20 dan kam yoki teng | ＋15.0%(min＋0,45mm) －12,5% －0,35 mm) |
±10%(min±0,30mm) | |
| ＞20 | ±12.5% | ±10% | ||
| OD 351 dan katta yoki unga teng | ±15% | |||
| Sovuq tortilgan quvur | OD | 10-30 | ±0.40mm | ±0.20mm |
| ＞30-50 | ±0,45 mm | ±0,25 mm | ||
| ＞50 | ±1.0% | ±0.75% | ||
| WT | 1.5-3.0 | +15% -10% |
±10% | |
| ＞3.0 | +12.5% -10% |
±10% | ||
