General standards and technical requirements for steel pipes and pipe fittings

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1. Main standards and specifications: https://pics2.baidu.com/feed/9c16fdfaaf51f3de494c67be4b913a15382979fd.jpeg?token=4aecdc7d24f70dc9cf3d571c5ee2cfb1 Note: This item should list in detail the current ** and industry-specific effective standards and specifications based on the specific materials. https://pics4.baidu.com/feed/4e4a20a4462309f7699039f3aa71c6f9d5cad6db.jpeg?token=539e23583260262ff83f24d134a7d8d0 Steel butt-welded seamless pipe fittings https://pics7.baidu.com/feed/8cb1cb13495409232a3a55f84f271b03b2de496b.jpeg?token=80c4750aea279e18b77aeafe2b0da2a7 Steel butt-welded seamless pipe fittings https://pics6.baidu.com/feed/79f0f736afc379318f59785b34bb7d4f43a9111d.jpeg?token=0776f76091969d9941d0c8115474fe8d Steel butt-welded seamless elbows https://pics2.baidu.com/feed/b90e7bec54e736d13e8f7587412f85c8d462692f.jpeg?token=904f97840cb1d371e9e714316c841373 Steel butt-welded seamless elbows 2. Product technical requirements 2.1 Technical requirements for steel pipes A. The working steel pipes shall be double-sided submerged arc spiral pipes; the tolerances and properties regarding the nominal diameter and outer diameter of these pipes shall comply with GB/T9711-2017, with no negative deviations allowed. B. The material used is Q235B; for spiral-welded steel pipes, it is required that they be manufactured by welding sheets of metal together. Each pipe must be formed by welding an entire sheet of metal, and it is not allowed for two or more sheets to be combined to form the pipe. The standard length of each steel pipe is 12 meters, and there are no minimum requirements regarding the wall thickness of the pipes. https://pics4.baidu.com/feed/b03533fa828ba61e90093d5fae4b5d00314e5961.jpeg?token=d8ef3d67a502e84a76e62367f4a0b9f8 Seamless steel pipes for transporting fluids https://pics2.baidu.com/feed/b3b7d0a20cf431ad86df042ea24966a52edd9826.jpeg?token=e1dabc3e9f230492d0055fcfc8c678da Steel pipes https://pics7.baidu.com/feed/f7246b600c338744c06a60b68a7013f3d52aa0d3.jpeg?token=2cf63299404efbf7bf4a6897f0279b1e Seamless steel pipes for transporting fluids C. Technical requirements for seamless steel pipes: The dimensions, shape, weight, allowable tolerances, and material of seamless steel pipes shall comply with the provisions of GB/T8163-2018. The material requirement is 20# steel. D. The two end faces of the steel pipe shall be perpendicular to the axis of the pipe; the tilt of these ends shall not exceed 5 mm, and the height of any burrs on the inner or outer surfaces shall not be greater than 0.5 mm. E. Surface quality: Depending on the corresponding manufacturing method of the pipe, its inner and outer surfaces should be smooth, with no defects such as folding, cracking, delamination, or lap welding allowed. An increase in the weld wall thickness is allowed. F. The working steel pipes shall meet the following requirements: The surface of the working steel pipes must be pre-treated to remove rust, scale, grease, dust, paint, moisture, or other contaminants. The rust removal level on the outer surface of these pipes shall comply with the Sa2.5 standard specified in GB/T8923.1. G. Upon delivery, the steel pipes are accompanied by the factory certification of conformity, material sheets, and quality verification documents such as test reports (including hydrostatic testing, ultrasound, and X-ray tests). H. Service life: The expected service life of the insulation pipe at a continuous operating temperature of 130°C is not less than 30 years. Comply with **the current highest industry standards. 2.2 Elbows, tees, and reducers 2.2.1 Elbows/curved pipes For pipe diameters of A.DN500 and above, or when the bending radius is less than 1.5D, welded elbows made of steel plates can be used (GB/T13401-2017); for elbows with a bending radius of 2D or more, seamless pipes or spiral-welded pipes are used for hot bending. Elbows with a diameter smaller than DN500 are manufactured by hot bending seamless pipes. The bending radius of elbows is generally 1.0DN, 1.5DN, 2.5DN, 4.0DN, and 6D.