LSAW Steel Pipe

　　Residual stress is the member which has not been exposed to the initial stress loads on the section member already exists many causes, wherein the welding residual stress is a very important one, in addition to the steel in the process will produce stresses involved during welding is a weldment local heating process and then gradually cooled, non-uniform temperature field will allow each part of the weldment uneven deformation, resulting in a variety of welding residual stresses. Internal stress of welded components generated by the welding called welding stresses the role of time can be divided by the instantaneous welding stress and welding residual stress. A welding process, welding stress is called instantaneous instantaneous welding stress, which change over time. After remaining in the weldment welding residual stress is called stress. For steel, the welding residual stress and deformation structure is an important factor affecting the fracture strength, fatigue strength and st...

　　Water supply is essential for the use of steel pipes and conical steel pipes to cause “secondary pollution” in pipeline transportation. In daily life, the quality of drinking water and the safety of water pipes are the core of people's lives. Metal pipes have four major drawbacks: easy to rust, perishable, easy to leak, and prone to scaling. When the galvanized tapered steel tube is corroded, it will breed various microorganisms. Conical steel pipe. Bacteria in tap water are like tangible killers that constantly force people to be healthy. 　　In the past 10 years, some wealth-prone countries have enacted legislation or established industry regulations to stop the use of double-sided lsaw steel pipes as drinking water pipes, and it is recommended to use green pipes as the main body, without rust, corrosion and leakage. Excellent pipelines have no scale. 　　The standards for the implementation of straight seam steel pipes are those allowed by the standards and standards allowed b...

　　Cold drawn seamless tube is used for high dimensional accuracy mechanical structure, hydraulic equipment and good surface finish cold drawn or cold rolled precision seamless steel tubes. High-precision drawing denotes the outer diameter size precision (tolerance) strict and external surface finish, roundness, straightness good thickness uniformity. 　　Heat treatment of cold drawn seamless steel pipe : 　　(1)cold drawn steel annealing: refers to the metal material is heated to the appropriate temperature, to maintain a certain time, and then slowly cooled heat treatment process. Common annealing process are: recrystallization annealing, stress relieving, ball annealing, fully annealed and so on. The purpose of annealing: mainly to reduce the hardness of the metal material, to improve the plasticity, or cutting processing to Liqie pressure processing, reduce the residual stress and improve the uniformity of microstructure and composition, heat treatment, after possible or tissue prep...

　　Because ssaw steel pipe can be made by a coil width continuous forming welding production, easy automation, and using double-sided automatic submerged arc welding type, there are a variety of testing method to check weld quality assurance checks. Therefore, when laying oil pipelines, spiral welded pipe has been widely used. However, in forming the welding process, the process by mistake or due to other reasons mature operation, resulting in a variety of pipe defects generated. 　　Lack of fusion 　　No penetration weld means between the base metal and the base metal, not the spaces left by the arc melting, the double-sided spiral welded pipes produced generally in the middle of the weld. Due to the use of double-sided spiral submerged arc welded pipe, it is not automatic weld penetration welded joints of the causes, which is too small for the gap, too small welding current and welding speed is too fast, or if improper wire angle welding arc is caused by partial blow When it is not p...

　　3PE anti-corrosion steel pipe for buried pipeline life is critical, the same material pipes buried in the ground for decades and some non-corrosive, and some years it leaks occur. Because they use different outer coating. 　　In which ordinary steel for use in harsh environmental conditions, there will be severe corrosion, which will reduce the life of the steel pipe, steel pipe anti-corrosion insulation life is relatively long, generally, it can be used under normal circumstances for 30-50 years, and the proper installation and use is also possible to make the pipe network maintenance costs low, anti-corrosion pipe insulation can also set an alarm system, automatic leak detection pipe network failures, accurate knowledge of fault location and will automatically alarm. 　　3PE anti-corrosion steel pipe insulation performance is good, heat loss is only 25 per cent of the traditional pipe, long run can save relatively large resources, significantly reduce energy costs, and still has a ...

　　The first one is flux-cored wires. When welding out of position on thick-walled welded steel pipe, it is better to choose gas-shielded flux-cored wire to achieve high deposition rates. This kind of filler metal can weld out of position without a special power, and the flux coating on the wire can be considered as a dam which can hold the molten weld pool in place. Therefore, the flux –cored wires are useful for improving productivity. However, there are some disadvantages when using the flux-cored wires in the welded steel pipe . Higher levels of smoke may be produced and a slag may be generated by the wires. Then both between passes and after the cap pass, the welding operators will need to chip or grind in, which in turn leads to greater downtime for cleanup. 　　The other kind is metal-cored wires. When welding welded steel pipe, the metal-cored wires are accepted more and more widely. The available diameters of the metal-cored wires range from 0.035- to 1/16-inch. In order to wel...

　　In the welding process of large welded steel pipe, we should pay great attention to the melted region of the work piece and form a molten solder, because the melted region is the connection of cooling and solidifying the material after the pool is formed. Usually, the pressure is required by large diameter thick-walled pipe in welding process. There are many welding energy sources, for example, a gas flame, electric arc, laser, electron beam, friction and ultrasonic. 　　The first one is a board probe. In the process of welding welded steel pipe, after the welded steel pipe enters the production, the manufacturers use it to manufacture large diameter submerged arc welding of steel pipes. In addition, whether there are internal defects pipe can be checked by the first full-board ultrasonic test. 　　Then, the milling, which can ensure the width of welded steel pipe reach to target diameter when the milling machine is through the two-sided edge of the milling pipe, so the width of the...