|
外径和壁厚的允许偏差
|
钢管种类 |
钢管尺寸 |
允许偏差 |
|
|
|
普通级 |
高级 |
|
|
|
|
热轧(挤，压)管 |
外径 D |
<50 |
± 0.50 mm |
± 0.40mm |
|
≥50 |
± 1 % |
± 0.75 % |
|
|
|
壁厚 |
〈4 |
± 12.5 % (最小值为±0.40mm) |
± 10 % (最小值为±0.30mm) |
|
|
≥4~20 |
+15% -12.5% |
± 10 % |
|
|
|
>20 |
± 12.5% |
± 10% |
|
|
|
冷拔(轧)管 |
外径 |
6~10 |
± 0.20 mm |
± 0.10 mm |
|
>10~30 |
± 0.40 mm |
± 0.20 mm |
|
|
|
|
>30~50 |
± 0.45 mm |
± 0.25 mm |
|
|
>50 |
± 1 % |
± 0.5 % |
|
|
|
壁厚 |
≤1 |
± 0.15 mm |
± 0.12 mm |
|
|
>1~3 |
+ 15 %, - 10 % |
± 10 % |
|
|
|
>3 |
+ 12.5, - 10 % |
± 10 % |
|
|
注:对外径不小于351mm的热扩管，比后允许偏差为± 18 %+
