20G, Boiler steel pipe Posted on 14 November, 2012 20G is the steel material of GB 5310- 2008. GB 5310- 2008 standard is applicable to seamless tubes for making steam boiler whose pressure is high or higher and seamless tubes used as pipelines。
Chemical Compositions(%) of 20G：
| Chemical elements | Carbon | Silicon | Manganese | Phosphorus | Sulfur | Chromium | Molybdenum | Cuprum | Nickel | Vanadium |
| Data | 0.17-0.24 | 0.17-0.37 | 0.70-1.00 | 0.03 | 0.03 | 0.25 | 0.15 | 0.2 | 0.25 | 0.08 |
Mechanical Properties of 20G：
| Properties | Data |
| Yield Strength (Mpa) | ≥415 |
| Tensile Strength (Mpa) | 240 |
| Elongation (%) | 22 |
The W.T. tolerance of 20G：
| W.T.(S) | Tolerance of W.T. | |
| <3.5 | +15%(+0.48mm min) | |
| -10%(+0.32mm min) | ||
| 3.5-20 | +15%,-10% | |
| >20 | D<219 | ±10% |
| D≥219 | +12.5%,-10% | |
MECHNICAL PROPERTIES (Minimum Values) :
| Grade | Chemical Composition | ||||||
| C | Si | Mn | P | S | Cr | Mo | |
| 20G | 0.17~0.23 | 0.17~0.37 | 0.35~0.65 | ≤0.025 | ≤0.015 | − | − |
| 20MnG | 0.17~0.23 | 0.17~0.37 | 0.70~1.00 | ≤0.025 | ≤0.015 | − | − |
| 25MnG | 0.22~0.27 | 0.17~0.37 | 0.70~1.00 | ≤0.025 | ≤0.015 | − | − |
| 15MoG | 0.12~0.20 | 0.17~0.37 | 0.40~0.80 | ≤0.025 | ≤0.015 | − | 0.25~0.35 |
| 20MoG | 0.15~0.25 | 0.17~0.37 | 0.40~0.80 | ≤0.025 | ≤0.015 | − | 0.44~0.65 |
| 12CrMoG | 0.08~0.15 | 0.17~0.37 | 0.40~0.70 | ≤0.025 | ≤0.015 | 0.40~0.70 | 0.40~0.55 |
DIMENSION TOLERANCE:
| Processing | Pipe Sizes (mm) | Tolerances | ||
| Cold Drawn | OD | ≤25.4 | ±0.15 | |
| >25.4~40 | ±0.20 | |||
| >40~50 | ±0.25 | |||
| >50~60 | ±0.30 | |||
| >60 | ±0.5% D | |||
| WT | ≤3.0 | ±0.3 | ||
| >3.0 | ±10% S | |||
INSPECTION AND TEST: Chemical Compostion Test. Mechanical Properties Test(Tensile Strength, Yield Strength, Elongation, Flaring, Flattening, Hardness, Etc). Surface And Dimension Check. Non-Destructive Test(Eddy Current Test/Ultrasonic Test), Hydraulic Test. Description: GB 5310 SEAMLESS HIGH PRESSURE TUBE FOR BOILER used for high pressure service. High pressure boiler, pressure equipment, superheater, pipeline, preheating tubes, etc. Top quality products Applications: Mainly used for high pressure service. High pressure boiler, pressure equipment, pipe line, superheater, preheating tubes, etc. Competitive Advantage: GB 5310 is one of our most popular products. We always put quality on first consideration makes us keep our qulity stable and good. Always put customer’s benefit before ours makes our good service and gain us good reputation. Advanced equipments. Sincere , truth and careful attitude on communication and production.
