GB/T8163 Seamless Steel Tube for Liquid Transpotation 20 Q345
Application of Seamless Steel Tube: for Liquid Transpotation
Production method: Hot - rolled /Cold - drawn /cold - rolled)
Permissible Tolerance of Outer Diameter and Wall Thickness (mm)
|Type of steel Tube||Dimension of steel tube||Permissible tolerance|
|Average class||High class|
(extruded and expanded) tube
|Outer diameter D||All||±1%|
|Cold-drawn (cold-rolled) tube||Outer diameter D||6~10||±0.2||±0.15|
|Note: For hot-expanded tubes with outer diameter≧35mm,the permissible
tolerance of wall thickness is±18%.|
Technical Specifications :
Steel tubes are made of Grade 10, 20, Q205, Q345 steel.
Steel tubes of other grades can be produced as required by the
client and through mutual discussion between the client and the
Method of manufacturing :
hot-rolled (extruded and expanded) and cold-drawn (cold-rolled)
Steel shall be made by electric furnace, Martin furnace or oxygen
converter. When the client specified a certain method of
manufacturing, it shall be indicated in the contract.
Steel tubes shall be manufactured by hot-rolled (extruded and
expanded) and cold-drawn (cold-rolled) seamless process. When the
client specified a certain method of manufacturing, it shall be
indicated in the contract.
Hot-rolled (extruded and expanded) steel tubes are delivered in
hot-rolled or heat-treated status while cold-drawn (rolled) steel
tubes are delivered in heat-treated status.
Longitudinal Mechanical Properties of Steel Tubes
|NO.||Steel Grade||Tensile Strength(Mpa)||Yield point(Mpa)||Elongation after breaking(%)|
|Not less than|
Hydrostatic pressure test
No crack, folding, rolled scrimp, separation layer and scab are
allowed to exist. These defects shall be completely removed and the
removal depth shall not exceed the negative tolerance of the
nominal wall thickness.