stainless steel welded pipe

This technical specification is suitable for the bidding for the procurement of steel pipe projects. Executive standards The steel pipe shall meet the following standards: Quality standard like Spiral Welded Submerged Arc Welded Steel Pipes for Urban Heating CJ/T3022-1993 or Technical Delivery Conditions of Oil and Gas Industry Transportation Steel Pipes GB/T9711.1-2017 should be implemented for spiral welded pipes. Seamless Steel Pipe for Fluid Transportation GB/T8163-2008 should be carried out as quality standards for seamless steel pipes. Technical requirements for steel pipes Materials The steel pipe should be made of spiral seam welded steel pipes with Q235B.  The seamless steel pipe should adopt 20# steel. Technical specifications The quality and size of spiral seam welded steel pipes should conform to IS09330-1 or GB9711.1～2017 standards. Spiral seam welded steel pipes should ensure that the minimum yield strength is greater than 235N/mm2. Weld joints of steel pipes must meet the technical requirements of DIN1626 or GB3323-87. Specifications, weights and errors of steel pipes The supply of steel pipes shall comply with the relevant regulations in the latest GB9711.1-2017 or GB8163-2008. The normal supply length of the steel pipe should be 12m with a length deviation of 0/+25mm.  When the length of the steel pipe is less than 12m due to the valve, compensator or pipeline turning, it should be supplied according to the actual length on site. The thickness deviation requirements of the raw material steel plate of the steel pipe: when DN is 800mm, the negative thickness deviation should be smaller than or equal to 0mm.  When DN is greater than 800 and smaller than or equal to 1100mm, the thickness negative deviation should be less than or equal to 0mm.  When DN is greater than 1100 and smaller than or equal to 1200mm, the thickness negative deviation should be less than or equal to 3%. The end of the steel pipe should be grooved.  The groove angle should be 30° and the deviation 0°/5°.  The size of the blunt edge should be 1.6±0.8mm. The end surface of the steel pipe shall be perpendicular to the axis of the steel pipe.  When the nominal outer diameter is less than 508mm, the limit deviation shall not be greater than 1.5mm.  When the nominal outer diameter is greater than or equal to 508, the limit deviation shall not be greater than 2.0mm. The ovality of the steel pipe end within 100mm shall not exceed ±1%D. Requirements for manufacturers In order to ensure the quality of the project, the following requirements are put forward for the materials and manufacturers of steel pipes and fittings: The steel quality standards of steel pipes are equal to or higher than those of famous steel pipe manufacturers in China. The quality standard of the steel pipe is equal to or higher than the product standard produced by the bidder, and the selected manufacturer must be approved by the tenderer and indicate in the bidding document. At the same time, photocopies of the delivery quality certificate of the steel pipe raw materials, the quality certificate of the steel pipe, the special equipment manufacturing license (pressure pipe) that the manufacturer should have, and the inspection report issued by the local quality inspection department must be attached to the bidding documents.

It mainly uses steel wire brush and other tools to polish the steel surface, which can remove loose or raised oxide skin, rust, welding slag, etc. Generally, chemical and electrolytic methods are used for pickling treatment. Chemical pickling is only used for pipeline corrosion protection, which can remove oxide skin, rust and old coating. Sometimes it can be used as the reprocessing after sand blasting. Although chemical cleaning can make the surface reach a certain degree of cleanliness and roughness, its anchor pattern is shallow and easy to pollute the environment. Spray (throwing) rust removal is a high-speed rotation of spray (throwing) blades driven by a high-power motor, so that steel sand, steel shot, wire section, minerals and other abrasives can spray (throwing) on the ASTM A106 A53 Gr. B Carbon Steel Seamless Fluid Pipe surface under the centrifugal force, which can not only completely remove rust, oxides and dirt, but also achieve the required uniform roughness under the action of strong impact and friction of abrasives. After spraying (throwing) and removing rust, not only the physical adsorption on the pipe surface can be expanded, but also the mechanical adhesion between the anticorrosive coating and the pipe surface can be enhanced. Therefore, spraying (throwing) is an ideal way to remove rust. Generally speaking, shot blasting (sand) is mainly used for inner surface treatment of pipes, while shot blasting (sand) is mainly used for outer surface treatment of pipes.