GB/T 3087 Grade 20 Seamless Boiler Tubes
GB 3087 Grade 20 Seamless Boiler Tubes,GB 3087 Grade 20 Seamless steel pipe for low and medium pressure boilers

Description

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

 

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%