GB 3087 Grade 20 Seamless Boiler Tubes
GB 3087 Grade 20 Seamless Boiler Tubes
Standard:GB 3087
GB 3087——Seamless steel pipe for low and medium pressure boilers
GB 3087 standard is applicable to the manufacture of high-quality carbon structural steel hot-rolled (extruded, expanded) and cold drawn (rolled) seamless steel tubes for various structural low-pressure and medium-pressure boilers and locomotive boilers.
GB 3087 Grade 20 Seamless steel pipe for low and medium pressure boilers
GB 3087 Grade 20 Seamless Boiler Tubes Quick Details
Manufacture:Seamless process ,Hot-finished or Cold-finished
Wall thickness(WT): 3.2 mm——21 mm.
Outer diameter (OD): 33 mm——323 mm
Length: 6M or specified length as required.
Ends: Plain End, Beveled End, Treaded
Additional Info
Port of Shipment: Tianjin, China
Payment Terms:T / T, LC
Delivery: 7-15 days after payment
Surface: Tubes will be varnished (Outside only) to prevent rust.
Marking: Standard + Steel Grade + Size + Heat No + Lot No
Package: Bundles (hexagonal),Wooden Boxes,Crates (steel/wooden) or as required
Manufacturing methods
(1)Method of manufacturing steel
Steel are manufactured by electric furnace, oxygen converter or open hearth method.
(2)Manufacturing method of tube blank
The tube blank can be produced by a hot rolling method, and a continuous casting billet or a steel ingot can also be used.
(3)Manufacturing method of steel pipe
The steel pipe can be manufactured by a hot rolling (extrusion, expansion) or cold drawing (rolling) seamless method.
Delivery status
Steel pipes shall be delivered in hot rolled or heat treated condition.
The finishing temperature of the steel pipe delivered in the hot rolled state shall not be less than Ar3.
Chemical composition of GB 3087 Grade 20
| Grade | Chemical Composition(%) | |||||||
| C | Si | Mn | P | S | Cr | Cu | Ni | |
| 20 | 0.17～0.23 | 0.17～0.37 | 0.38～0.65 | ≤0.030 | ≤0.030 | 0.3～0.65 | ≤0.25 | ≤0.30 |
Mechanical properties of GB 3087 Grade 20
| Grade |
Wall thickness (mm) |
Tensile strength (MPa) |
Yield Strength (MPa) |
Elongation % |
| ≥ | ||||
| 20 | ＜15 | 410～550 | 245 | 20 |
| ≥15 | 225 | |||
Allowable deviation of outer diameter and wall thickness
| Type of steel pipe | Outer diameter(mm) | Tolerance | ||
| ordinary | advanced | |||
| Hot rolled tube | OD | ≤159 | ±10%（min±0.50mm） | ±0.75%(min±0.40mm) |
| ＞159 | ±1.0% | ±0.90% | ||
| WT | ≤20 |
＋15.0%(min＋0.45mm) －12.5% －0.35mm) |
±10%（min±0.30mm) | |
| ＞20 | ±12.5% | ±10% | ||
| OD≥351 | ±15% | |||
| Cold drawn tube | OD | 10～30 | ±0.40mm | ±0.20mm |
| ＞30～50 | ±0.45mm | ±0.25mm | ||
| ＞50 | ±1.0% | ±0.75% | ||
| WT | 1.5～3.0 |
+15% -10% |
±10% | |
| ＞3.0 |
+12.5% -10% |
±10% | ||
Testings
(1)Hydraulic test
The steel pipe should be hydraulically tested one by one.
(2)Flattening test
Steel pipes with an outer diameter of more than 22mm to 400mm and a wall thickness of not more than 10mm shall be subjected to a flattening test.
(3)Flaring test
The steel pipe with a wall thickness of not more than 8 mm can be subjected to a flare test with a top taper of 30°, 45° or 60°.
(4) Bending test
Steel pipes with an outer diameter of not more than 22 mm will be subjected to a bending test
(5)Non-destructive testing
According to the requirements of the purchaser, the steel pipe will be ultrasonically tested one by one.
Surface quality
The inner and outer surfaces of the steel pipe do not have cracks, folds, creases, crusting or separation, and these defects should be completely removed. The clearance depth shall not exceed the negative deviation of the nominal wall thickness, and the actual wall thickness at the cleaning site shall not be less than the minimum allowed by the wall.
Packaging, marking and quality instructions
The packaging, marking and quality specifications of steel pipes shall comply with the provisions of GB/T 2102.
Photos of GB 3087 Grade 20 Seamless Boiler Tubes
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