GB/T 3087 20# seamless steel pipe is made of steel ingot or solid tube blank by piercing, then hot rolling, cold rolling or cold drawing.
GB/T 3087 20# seamless steel pipe refers to the steel with open ends and hollow section, and its length is larger than the surrounding steel. According to the production method, it can be divided into seamless steel pipe and welded steel pipe. The boiler steel pipe specification uses the overall dimension. GB/T 3087 20# seamless steel pipe can be used for pipeline, thermal equipment, mechanical industry, petroleum geological exploration, container, chemical industry and special purpose.
GB/T 3087 20# seamless steel pipe chemical composition
| Grade |
C |
Mn |
Si |
P |
S |
Cr |
Ni |
Cu |
|
20# |
0.17-0.23 |
0.35-0.65 |
0.17-0.37 |
0.035 |
0.035 |
0.15 |
0.30 |
0.25 |
GB/T 3087 20# seamless steel pipe mechanical properties
| Grade |
Tensile strength |
Yield strength |
Elongation % |
|
GB/T 3087 20# |
410-550 |
245 |
20 |
GB/T 3087 20# seamless steel pipe outside diameter tolerance
| Hot rolled |
Outside diameter, mm |
Tolerance |
|
All |
±1.0% or ±0.50mm |
|
Cold drawn |
Outside diameter, mm |
Tolerance |
|
All |
±1.0% or ±0.30mm |
GB/T 3087 20# seamless steel pipe wall thickness tolerance
| Hot rolled |
Outside diameter, mm |
Tolerance |
|
OD≤102 |
±12.5% or ±0.40mm |
|
OD>101.6, WT/OD≤0.05 |
±15% or ±0.40mm |
|
OD>101.6, 0.05 ＜WT/OD≤0.10 |
±12.5% or ±0.40mm |
|
OD>101.6, WT/OD>0.10 |
+12.5%/-10% |
|
Cold drawn |
Wall thickness, mm |
Tolerance |
|
OD≤3 |
+15%/-10% or ±0.15mm |
|
OD>3 |
+12.5%/-10% |
Production and manufacturing method of GB/T 3087 20# seamless steel pipe: the service temperature of general boiler steel pipe is below 350, and GB/T 3087 20# seamless steel pipe is often in high temperature and high pressure condition.
Under the action of high temperature flue gas and steam, GB/T 3087 20# seamless steel pipe will have oxidation and corrosion, and GB/T 3087 20# seamless steel pipe has high endurance strength, high oxidation resistance and corrosion resistance, and good structural stability.
GB/T 3087 20# seamless steel pipe is mainly used to manufacture superheater tube, reheater tube, air duct and main steam pipe of high pressure and ultra-high pressure boiler.
