The Seamless steel pipe for ship building usage is mainly used for Level 1 & Level 2 pressure pipe in piping system, boiler and super-heated unit of shipbuilding.
Seamless steel pipes 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 Lloyd’S 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 pipes for manufacturing marine boilers and ovemeaters as we as pressure pipes opf grade I and Ⅱ．
Model N0．of major steel tube320，360，410，460，490，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％
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