?the 20# seamless steel pipe material quality is the 20# steel, the strength ratio 15 steel is slightly high, very little quenches, non-temper brittleness. The cold-work plasticity high, generally for curving, the rolling, curved side and the hammer arches and so on processings, the arc welding and the contact welding welding performance is good, when gas welding thickness is small, the contour request strict or on the shape complex workpiece easy to have the crack. The cutting workable cold draw or the hot condition compare the annealed condition to use in well, making the stress generally but toughness requests high not greatly. ??the 20# seamless steel pipe's material is: High quality carbon structural steel ??Trademark: 20 steel ??Standard: GB8162-2008 GB/T8163-2008 GB3087-2008 GB9948-2006 ??The strength ratio 15 steel are slightly high, very little quenches, non-temper brittleness. The cold-work plasticity high, generally for curving, the rolling, curved side and the hammer arches and so on processings, the arc welding and the contact welding welding performance is good, when gas welding thickness is small, the contour request strict or on the shape complex workpiece easy to have the crack. The cutting workable cold draw or the hot condition compare the annealed condition to use in well, making the stress generally but toughness requests high not greatly. ??* chemical composition: ??Carbon C: 0.17~0.24 " silicon Si:0.17~0.37 manganese Mn:0.35~0.65 sulfur S: ?0.035 phosphorus P: ?0.035 chromium Cr:?0.25 nickel Ni:?0.25 copper Cu:?0.25 ??* mechanical properties: ??Tensile strength ?b (MPa):?410(42) yield strength ?s (MPa):?245(25) elongation ratio ?5 (%): ?25 reduction of area Psi (%): ?5, degree of hardness: Not heat treatment, ?156HB, test specimen size: Test specimen size 25mm ??* heat treatment regime and Microstructure: ??Heat treatment regime: Hot, 910?, air cooled. Microstructure: Ferrite + pearlyte. ??* delivery state: By not heat treatment either heat treatment (annealing, normalizing or high tempering) condition delivery. The request heat treated condition delivery should indicate in the contract, not indication according to not heat treatment delivery. ??20# seamless steel pipe related knowledge ??1.1 steel pipe nominal outer diameter is 88.9mm, nominal wall thickness is 6.45mm. ??1.2 steel pipe's outer diameters and wall thickness allowable deviation should conform to Table 1 stipulation. Shows outer diameter allowable deviation + 0.50mm - 0.20mm wall thickness allowable deviation + 0.97mm - the 0.77mm 2 steel pipe's normal lengths is 9400mm~9750mm. ??3 contour 3.1 steel pipe's bendings do not be bigger than 1.0mm/m. ??3.2 steel pipe both sides end surface should with the steel pipe spool thread vertical, the margin burr should give the elimination. ??4 weight steel pipes according to the actural weight delivery, may also according to the theoretical weight delivery. The steel pipe each meter theoretical weight is 13.115kg/m. ??5. steel pipe's end product chemical composition allowable deviation should conform to the GB/T 222 concerned requirements. ??6. delivery state steel pipe by hot rolling condition delivery. ??7. the mechanical properties after the suitable heat treatment, steel pipe's mechanical properties should achieve in API SPEC 5CT the N80 grade of steel request. ??8. the dense steel pipe should chase the root to carry on the turbulent flow crack detection take to examine steel pipe's dense, the turbulent flow crack detection contrast test specimen artificial defect through hole diameter as ?2.2mm±0.01mm. list go?steel pipe,steel suppliers,steel tubing,steel tubing prices
