First, the implementation standards of 20# seamless steel pipes:
- GB/T8162 seamless steel pipes for structures
- GB/T8163 seamless steel pipes for fluids
- GB/T3087 seamless steel pipes for low and medium-pressure boilers
- GB/T5310 seamless steel pipes for high pressure boilers
- GB/T6479 seamless steel pipes for high pressure fertilizer equipment
- GB/T9948 seamless steel pipes for petroleum cracking
Second, industrial details of 20# seamless steel pipes
Chemical composition of 20# seamless steel pipes: carbon: 0.17~0.23, silicon: 0.17~0.37, manganese: 0.35~0.65, phosphorus: ≤0.030, sulfur: ≤0.030, chromium: ≤0.25, nickel: ≤0.30, copper: ≤0.20.
Mechanical properties of No. 20 seamless steel pipe: tensile strength 410~530MPa, yield strength ≥245MPa, elongation after fracture, ≥20
Product specifications of No. 20 seamless steel pipe: outer diameter 10~1220mm, wall thickness 1.0~160mm.
Production methods of No. 20 seamless steel pipe: hot rolling, cold drawing, fine rolling, hot expansion.
For 20# and brand steel pipes with an outer diameter greater than 22mm~600mm and a wall thickness to outer diameter ratio of not more than 10%, a flattening test should be carried out. The flattening test plate spacing H is calculated according to the formula. After the flattening test, no cracks or cracks should appear on the sample.
Third, the expansion of 20# seamless steel pipe
According to the requirements of the buyer, after negotiation between the supply and demand parties, and indicated in the contract, for No. 20 steel pipes with an outer diameter not greater than 76 mm and a wall thickness not greater than 8mm, an expansion test can be carried out. The taper of the expansion test core is one of 30°45°60°. The expansion rate of the outer diameter of the expanded sample shall comply with the provisions of Table 9, and no cracks or fissures shall appear in the expanded sample.
Fourth, the ordering content of 20# seamless steel pipe
The contract or order for ordering steel pipes according to this standard shall include the following contents:
Standard number; product name; steel grade, quality grade if there is a quality grade; size specification; ordered quantity (total weight or total length); delivery status; special requirements. Size, shape, and weight
Fifth, the outer diameter and wall thickness of 20# seamless steel pipe
The nominal outer diameter D and nominal wall thickness S of the steel pipe shall comply with the provisions of GB/T 17395. According to the requirements of the demander, steel pipes with other outer diameters and wall thicknesses can be supplied after consultation between the supply and demand parties.
Post time: May-20-2025