● Classification of Ships
CCS Rules for Classification and Construction of Ships
BV Rules for Classification of Ships
LR Rules and Regulations for Classification of Ships
DNV Rules for Classification of Ships
ABS Rules for Classification of Ships
NK Rules for Classification of Ships
GL Rules for Classification and Construction
● Standard
GB/T5312-2009
● Uses
For the manufacture of marine boilers, superheaters and pressure-resistant pipes
● Deviation
Allowable deviation of outer diameter and wall thickness
| Outer diameter D | Hot rolled tube | Diameter size mm | ≤ 159 | ＞ 159 | |
| Allowable deviation % | ± 1.0 | ± 1.25 | |||
| Cold-drawn tube | Diameter size mm | ≤ 30 | ＞ 30~50 | ＞ 50 | |
| Allowable deviation | ± 0.20mm | ± 0.30mm | ± 0.8% | ||
| Wall thickness S | Hot rolled tube | Wall thickness mm | 3 ＜ S ≤ 20 | S ＞ 20 | |
| Allowable deviation % | +15-10 | ± 10 | |||
| Cold-drawn tube | Wall thickness mm | 1.5~3 | ＞ 3 | ||
| Allowable deviation % | +12-10 | ± 10 | |||
