According to GB/T8162-87, the specifications: hot-rolled pipe outer diameter 32 ~ 630mm. wall thickness 2.5 ~ 75mm. cold-rolled (cold-drawn) pipe outer diameter 5 ~ 200mm. wall thickness 2.5 ~ 12mm.
The internal and external surfaces of the steel pipe shall not be cracked, folded, rolled and folded, delaminated, haired and scarred defects exist. These defects should be completely removed from the removal of the wall thickness and outside diameter shall not be made to exceed the negative deviation.
The ends of the steel pipe shall be cut at right angles and burrs shall be removed. Wall thickness greater than 20mm steel pipe allows gas cutting and hot saw cutting. By agreement between the supply and demand sides can also not cut the head.
Expanded Information:
Hot rolled seamless pipe OD is generally larger than 32mm, wall thickness 2.5-200mm, cold rolled seamless steel pipe OD can be up to 6mm, wall thickness can be up to 0.25mm, thin-walled tubes OD can be up to 5mm wall thickness of less than 0.25mm, cold rolled than hot rolled dimensional accuracy.
General seamless steel pipe is made of 10, 20, 30, 35, 45 and other high-quality carbon steel 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other composite steel hot-rolled or cold-rolled.
10, 20 and other low-carbon steel made of seamless pipe is mainly used for fluid transportation pipeline. 45, 40Cr and other medium-carbon steel made of seamless pipe is used to make mechanical parts, such as automobiles, tractor parts of the force.
General use of seamless steel pipe to ensure the strength and flattening test. Hot-rolled steel pipe is delivered in hot-rolled state or heat-treated state; cold-rolled is delivered in heat-treated state.
Baidu Encyclopedia - Precision Seamless Steel Tube
Baidu Encyclopedia - Seamless Steel Tube