|  Standards：
GBl8248 Chinese national standard 
ASTMA519 Standard of American Society of Testing Materials
Application：
Used as seamless steel tubes of large calibers for manufacturing gas cylinders
Model
No.of major steel tubes：
4130X
Diamensional
tolerances:
|
Types of steel tubes |
Outer diameter |
Wall thickness |
|
Hot-rolled tubes |
Tube sizes(mm) |
Tolerances(mm) |
Tube sizes (mm) |
Tolerances(mm) |
|
φ559 |
±1.0％ |
17.0 |
－0％，＋25 |
Mechanical properties：
|
Standard codes |
Models of steel tubes |
Tensite strength（Mpa） |
Yield strength（Mpa） |
Yield ration |
Elongation（％） |
Absorbed-in-fracture energy（J） |
Hardness
|
|
Q/321088HGB3 |
4130X |
725～865 |
485～735 |
≤0.85 |
≥20 |
－40℃≥40 |
195～269HB | Chemical composition:
|
Standard codes |
Models of steel tubes |
Chemical compositions（％） |
|
C |
Si |
Mn |
P |
S |
Cr |
Ni |
Cu |
Mo |
V |
|
Q/321088HGB3 |
4130X |
0.25～0.35 |
0.15～0.35 |
0.40～0.90 |
≤0.020 |
≤0.010 |
0.80～1.10 |
≤0.25 |
≤0.20 |
0.15～0.25 |
≤0.08 | |
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