Metal & Oil & Gas News – 
The Seamless steel pipe for ship building usage are mainly used for Level 1& Level 2 pressure pipe in piping system, boiler and super-heated unit of shipbuilding.
Tubes for ship building
Seamless steel tubes for ship-building refer to the ship building steel pipes which are designed and manufactured for boilers,super heaters and pressure systems of ship. The ship building steel pipes can be expansively used in various kinds of ships such as CCS,DNV,LR,GL,ABS,BV,RINA,NK as well as China national standards.
Classification of ships:
Standard for malerials and wielding from Chinese classifying society Chinese clasifying society(CCS)
Standard of DNV Det Norske Veritas(DNV)
Standard of LloydS Register of UK(LR) Lloyd’S Register of UK(LR)
Standard of Germanischer Lloyd Germanischer Lloyd(GL)
Standard of American Bureau of Shipping(ABS)American Bureau of Shipping(ABS)
Standard of BUREAU VERITAS(BV)BUREAU VERITAS(BV)
Standard of RINA Italian classification society(RINA)
Standard of NIPPON KAIJI KYOKAI(NK)NIPPON KAIJI KYOKAI(NK)
GB/T5312 Chinese national standard
Appication:
Seamless steel tubes for manufacturing marine boilers and ovemeaters as we as pressure pipes opf grade I and II.
Seamless steel pipe for ship building usage, Tubes for ship building, Tubes for shipbuilding, ASTM A519-89/ASME SA519 SEAMLESS CARBON AND ALLOY STEEL MECHANICAL TUBING
Model N0．of major steel tubes320，360，410，460，490，etc．
Types of steel tubes | Outer diameters | wall thickness | ||
Cold-rolled tubes | Rube size(mm) | tolerances (mm) | Tube sizes (mm) | Tolerances (mm) |
＞30～50 | ±0.3 | ≤30 | ±10％ | |
＞50～219 | ±0.8％ | |||
Hot-rolled tubes | ＞219 | ±1.0％ | ＞20 | ±10％ |
Mechanocal properties：
Standard code | Models of steel tubes | Tensile strength（MPa） | Yield strength（MPa） | Elongation（％） |
GB/T5312 | 320 | 320～410 | ≥195 | ≥25 |
| 360 | 360～480 | ≥215 | ≥24 | |
| 410 | 410～530 | ≥235 | ≥22 | |
| 460 | 460～580 | ≥265 | ≥21 | |
| 490 | 490～610 | ≥285 | ≥21 |
Chemical compisition:
Standard code | Models of steel tubes | Chemical compisition（％） | ||||
C | Si | Mn | P | S | ||
GB/T5312 | 320 | ≤0.16 | ≤0.35 | 0.40～0.70 | ≤0.035 | ≤0.035 |
360 | ≤0.17 | ≤0.35 | 0.40～0.80 | ≤0.035 | ≤0.035 | |
410 | ≤0.21 | ≤0.35 | 0.40～1.20 | ≤0.035 | ≤0.035 | |
460 | ≤0.22 | ≤0.35 | 0.80～1.40 | ≤0.035 | ≤0.030 | |
490 | ≤0.23 | ≤0.35 | 0.80～1.50 | ≤0.035 | ≤0.030 | |
Note：
residual elements:Cr≤0.25％，Mo≤0.10％，Ni≤0.30％，Cu≤0.30％aggregate≤0.70％
