外径和壁厚的允许偏差
钢管种类 | 钢管尺寸 /mm | 允许偏差 | ||
普通级 | 高 级 | |||
热轧(挤压扩)管 | 外径D | <50 | ±O.50mm | 土0.40mm |
≥50 | ±1% | ±O.75% | ||
壁厚s | <4 | ±12.5%(*小值为±O.40mm) | ±lO%(*小值为±O.30mm) | |
≥4~20 | +15% -12.5% | ±10% | ||
>20 | ±12.5% | ±lO% | ||
冷拔(轧)管 | 外径D | 6~10 | ±O.20mm | 士O.10mm |
>lO~30 | ±O.40m | ±O.20mm | ||
>30~50 | ±O.45mm | ±0.25mm | ||
>50 | ±1% | ±O.5% | ||
壁厚s | ≤1 | ±0.15mm | 士O.12mm | |
>1~3 | +15% -lO% | 士lO% | ||
>3 | +12.5 -10% | ±lO% |
注:对外径不小于35lmm的热扩管,壁厚允许偏差为±18%。