Seamless steel tube for low medium
Pic-(Seamless steel tube for low medium)
Standard of implementation： Chinese GB3087
Application: used in low-pressure boiler (working pressure is generally greater than 5.88Mpa, working temperature at 450 below) of the heating surface pipe, collecting box and steam pipe
Major steel grade ： Grade10 、 20 （After consultation, can also provide other special grade of steel pipe）
Chemical composition and mechanical properties ：
Chemical composition and mechanical properties ：
| Standard | Steel grade | Chemical constituents (%) | ||||||
| C |
Mn
|
Si | Cr | Ni | Cu | P.S | ||
| GB3087 | 10 |
0.07～0.14
|
0.35～0.65 | 0.17～0.37 | ≤ 0.15 | ≤ 0.30 | ≤ 0.20 | ≤ 0.030 |
| 20 | 0.17～0.24 | 0.35～0.65 | 0.17～0.37 | ≤ 0.25 | ≤ 0.25 | ≤ 0.20 | ≤ 0.030 | |
| Mechanical properties | Tensile strength (MPa) | Yield strength (MPa) | Elongation (%) | |||||
| 10 | 335～475 | ≥ 195 | ≥ 24 | |||||
| 20 | 410～550 | ≥ 245 | ≥ 20 | |||||
Dimensional tolerance:
|
Type of steel tube
|
Steel tube size
mm
|
Deviation | ||
| Ordinary grade | Senior | |||
| Hot rolling (squeeze) tube | Outside diameter D |
≤159 | +1.0%(The minimum value is+0.50mm) | +1.0%(The minimum value is+0.5mm) |
| >159 | +1.0% | +1.0% | ||
|
Wall thickness S |
≤20 |
+15%(The minimum value is+0.45mm)
|
+1.0%(The minimum value is+0.30mm) | |
| -12.5%(The minimum value is-0.35mm) | ||||
| >20 | +12.5% | +10% | ||
| >20 | +12.5% | +10% | ||
| D≥351Heat expanding steel tube | +15% | |||
| Cold drawing (rolling) tube |
Outside diameter D |
10~30 | +0.40mm | +0.20mm |
| >30~50 | +0.45mm | +0.25mm | ||
| >50 | +1.0% | +0.75% | ||
|
Wall thickness S |
1.5~3.0 | +15% | +10% | |
| -10% | ||||
| >3.0 | +12.5% | +10% | ||
| -10% | ||||
