English | português | русский| Español

Our company


Hebei haihao high pressure flange & pipe fitting group was established in 1982, located in Mengcun County the hometown of pipe fittings in China.

Read More About Haihao Group

GB 20 carbon seamless steel for flange

This group of Chinese (GB) standard specifications covers carbon and alloy steel plates and forgings used in boilers and pressure vessels, high-strength low-alloy steels, heat-treatable steels, hot and cold-rolled plates for cold forming, steels for concrete reinforcement and prestressed concrete and the properties for railway service rails and accessories.

Standards for various types of steel pipe which specify requirements for high-temperature service, ordinary use, and special applications such as fire protection use, are also presented. Specifications for steel tubes list standard requirements for boiler and superheater tubes, general service tubes, still tubes in refinery service, heat exchanger and condenser tubes, mechanical and structural tubing. Steel casting specifications call out the standard properties for pressure purposes.

20# carbon steel is very common is china market under GB/T 699 standard. For GB/T 699 20# carbon steel, GB/T 699 20# round bar is mainly applied to machinery parts which requires high toughness and bears small stress,such as lever,axle sleeve,straining beam.

GB/T 699 20# round bar can also be used in the line of agricultural machinery or cars, to produce carburization or carbonitriding parts,such as lever shaft,plunger. GB/T 699 20# round bar is in a large need,so we henan bebon stock large quantity of forged bars in the warehouse, and various size round bars included. So if you need GB/T 699 20# round bar, pls be free to contact us.

GB/T 699 20# round bars are usually produced under the followed procedures: EAF arc furnace + LF purify affinage + VDF + ingot steel(bottom gating /argon) + forged + annealing + black polishing (turnery) + GB/T6402-92 ΙΙ UT test +  smooth edges with sawing .

GB 20# Carbon Steel Chemical Composition(WT%)

C Mn P S Ni Cr Si Cu
0.17~0.24 0.35~0.65 ≤0.040 ≤0.04 ≤0.25 ≤0.25 0.17~0.37 ≤0.25


GB 20# Carbon Steel Mechanical properties

Hardness Tensile Strength(Mpa) Yield Strength (Mpa) Elongation % An area of reduced %
GB 20# ≥420 ≥250 ≥25 ≥55


<< Back to Flanges

Haihao Group Twitter haihao group youtube haihao group facebook haihao group linkedin