Calculation method of structural steel pipe
Calculation method of structural steel pipe: (outer diameter - wall thickness) * wall thickness * 0.02466 = weight of steel pipe per meter 1. Seamless steel pipe for structure: gb8162-2008 2. Ground seam steel pipe for fluid transmission: gb8163-2008 3. Seamless steel pipe for boiler: gb3087-2008 4. High pressure seamless pipe for boiler: GB5310-2008 (ST45.8 - type III) 5. High pressure seamless steel pipe for chemical fertilizer equipment: GB6479-2000 6. Seamless steel pipe for geological drilling: yb235-70 7. Seamless steel pipe for oil drilling: yb528-65 8. Seamless steel pipe for petroleum cracking: GB9948-2006 9. Special seamless pipe for petroleum drill collar: yb691-70 10. Seamless steel pipe for automobile axle shaft: gb3088-1999 11. Seamless steel pipe for ships: gb5312-1999 12. Cold drawn cold rolled precision seamless steel pipe: gb3639-1999 13. Various alloy pipes 16Mn, 27SiMn, 15CrMo, 35CrMo, 12CrMoV, 20g, 40Cr, 12Cr1MoV, 15CrMo In addition, there are GB / t17396-2009 (hot rolled seamless steel pipe for hydraulic prop) Gb3093-1986 (high pressure seamless steel pipe for diesel engine) GB / t3639-1983 (cold drawn or cold rolled precision seamless steel tubes) GB / t3094-1986 (cold drawn seamless steel pipe, special-shaped steel pipe) GB / t8713-1988 (precision inner diameter seamless steel tubes for hydraulic and pneumatic cylinders) Gb13296-2007 (stainless steel seamless steel pipe for boiler and heat exchanger) GB / T14975-2002 (stainless steel seamless steel pipe for structure) GB / T14976-2002 (stainless steel seamless steel pipe for fluid transportation) GB / t5035-1993 (seamless steel pipe for automobile axle sleeve pipe) API Spec 5ct-1999 (Specification for casing and tubing), etc. Cold drawn (rolled) structural pipe: round pipe blank → heating → perforation → heading → annealing → pickling → oil coating (copper plating) → multi pass cold drawing (cold rolling) → blank pipe → heat treatment → straightening → hydrostatic test (flaw detection) → marking → warehousing. Hot rolling (extruded structural pipe): round pipe blank → heating → perforation → three roll cross rolling, continuous rolling or extrusion → pipe stripping → sizing (or reducing) → cooling → blank pipe → straightening → hydrostatic test (or flaw detection) → marking → warehousing.The following is an overview of the process flow of two structural pipes
The cold drawn structural pipe uses the hot-rolled steel coil as the raw material and carries out cold continuous rolling after acid pickling to remove the oxide scale. The finished product is the rolled hard coil. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of the rolled hard coil increase and the toughness and plasticity index decrease. Therefore, the stamping performance will deteriorate and can only be used for simple deformed parts. The hard rolled coil can be used as the raw material of the hot-dip galvanizing plant, because the hot-dip galvanizing units are equipped with annealing lines. The weight of rolled hard coil is generally 6 ~ 13.5T, and the inner diameter of steel coil is 610mm. Generally, continuous annealing (CAPL unit) or bell furnace annealing shall be carried out for cold rolled plates and coils to eliminate cold work hardening and rolling stress, so as to meet the mechanical property indexes specified in corresponding standards. The surface quality, appearance and dimensional accuracy of cold-rolled structural pipe are better than those of hot-rolled structural pipe, and its product thickness is right rolled to about 0.18mm, so it is favored by the majority of users. Taking cold rolled steel coil as the base structure pipe for deep processing of products, it has become a high value-added product. Such as electro galvanizing, hot galvanizing, fingerprint resistant electro galvanizing, color coated steel coil, vibration damping composite steel plate, PVC coated steel plate, etc., so that these products have beautiful, high corrosion resistance and other excellent quality, and have been widely used. Cold rolled steel coil must be finished after annealing, including head cutting, tail cutting, edge cutting, leveling, leveling, rewinding, or longitudinal shear plate. Cold rolled products are widely used in automobile manufacturing, household appliances, instrument switches, construction, office furniture and other industries. The weight of each bundle of steel plates is 3 ~ 5 tons. The weight of flattening coil is generally 3 ~ 10 tons / coil. The inner diameter of steel coil is 610mm. The hot-rolled structural pipe uses continuous casting slab or blooming slab as raw material, which is heated by stepping heating furnace and descaled by high-pressure water before entering the roughing mill. The roughing material enters the finishing mill after cutting head, tail and then enters the finishing mill for computer-controlled rolling. After final rolling, it is rolled into straight hair coil through laminar cooling and coiler. The head and tail of straight hair curl are often tongue shaped and fish tail shaped, with poor accuracy of thickness and width, and there are often defects such as wave shape, hem, tower shape and so on. The coil weight is heavy and the inner diameter of the steel coil is 760mm（ Generally, the pipe industry likes to use it.) After the straight hair coil is processed by head cutting, tail cutting, edge cutting, multi pass straightening, leveling and other finishing lines, it is then cut or rewound to become hot-rolled steel plate, flat hot-rolled steel coil, longitudinal cutting belt and other products. The hot-rolled finishing coil will become hot-rolled pickling coil if the oxide scale is removed by pickling and coated with oil. The product has the tendency to partially replace the cold-rolled structural pipe, with moderate price, and is deeply loved by the majority of users.