SSAW Pipe

　　Coat-Plating Methods of Galvanized steel Pipes 　　Hot dip galvanizing can protect steel pipes very well. When zinc is in liquid state, plate the steel with a thick layer of pure zinc after the complicated physical and chemical interaction and thus will make the hot dip galvanizing come into being. Also a zinc and steel alloy layer will be generated during this process. With this kind of layer and corrosion resistance feature, galvanized pipes can be applied to different severe corrosion environments, such as strong acid, alkali frog, etc., which is incomparable to other electro galvanizing. 　　Advantages of hot dip zinc galvanized pipes： 　　First, in general atmosphere, a very thin and dense layer of zinc oxide will be formed on the surface of zinc coating. It is hard to dissolve in water, therefore plays a certain protective effect to steel substrate. So, if the surface of steel pipe is covered with a quite thick and dense pure zinc layer, the steel substrate will be protected fr...

　　 Hot Dip Galvanizing 　　Since the standard electrode potential of zinc is lost to iron, galvanized layers in water and humid air have sacrificial anodes to protect the steel base, which can greatly extend the service life of the steel. Commonly used in the industrial galvanized layer of hot-dip galvanized, electro-galvanized, mechanical galvanizing and thermal spraying (plating) zinc, which accounted for about 95% of the total amount of hot-dip galvanizing, Accounting for 40% of zinc production in the world, accounting for about 30% of China's zinc production. 　　 Hot dip galvanized steel pipe , stainless steel, cast iron and other metals immersed in molten liquid metal or alloy in a coating technology. Hot-dip galvanizing, also known as hot-dip galvanizing, is a method in which a steel member is immersed in a molten zinc solution to obtain a metal coating. With the rapid development of high-voltage transmission, transportation and communication, the requirements for the protec...

　　Galvanizing Pickling and Washing 　　1, pickling steel pipe: 　　1) pickling workers must wear good labor protection before work, at work to seriously check the work site has no barriers, harness is intact, to confirm the good before the work. 　　2) pickling Mainly pickling hydrochloric acid, the use of water to the preparation of hydrochloric acid, hydrochloric acid content of 18 to 20% more appropriate. 　　3) pickling work before the first understanding of the concentration of acid, temperature and the tank pickling pipe tonnage. 　　4) hanging pipe when the two harnesses to leave the end of the first 1.3 meters to prevent hanging bending pipe, resulting in galvanized steel pipe leakage; in the acid tank to the next tube, the pipe to tilt 15 °, the first stand under their own end to prevent spray Acid wounding. 　　5) Each pickling of steel pipe , the weight of 2 to 5 tons is appropriate, time 5 to 15 minutes. 　　6) steel pipe in the pickling to frequent vibration in the process...

　 　Uses of Welded pipe 　　1. General welded pipes are used for the transportation of generally lower pressure fluids such as water, gas, air, oil and heating steam. 　　2. Ordinary carbon steel wire casing pipe (GB3640-88) is a steel pipe used to protect electric wires in electrical installation projects such as industrial and civil construction, installation machinery and equipment. 　　3. Straight seam welded pipe (YB242-63) is a steel pipe whose weld is parallel to the longitudinal direction of the steel pipe. Usually divided into metric electric welded pipe, welded thin-walled pipe, transformer cooling oil pipe and so on. 　　4. Spiral-slit submerged arc welded pipe (SY5036-83) for pressurized fluid conveying is a hot-rolled steel strip coil for tube blank, which is often spiral-formed by a double-sided submerged arc welding method for spiral conveying of pressurized fluid. Seam steel pipe. The steel pipe has strong pressure bearing capacity and good welding performance. It is saf...

　　Surface striated defects are important indicators affecting the surface quality of cold-rolled products . It is very difficult to solve the problem of surface ridges in many cold rolling mills in China, especially galvanizing units and continuous retreating units. The cause and solution of surface grain defects are an important part of the development of high-end cold-rolled product production technology. 　　How is the surface grain pattern formed? When the strip is subjected to a sudden transition from the elastic zone to the plastic zone by the stress exceeding the yield limit, due to the effect of the yielding platform, unevenness and local flow deformation will occur on the strip section, and the surface yielding transverse stripes will occur. The microscopic cause is due to the "nail anchor" effect of the Kodak air mass. When the solute atoms interact elastically with dislocations, they eccentrically gather around the dislocations to form a so-called "Kod's a...

　　 Steel pipes are the most widely used pipes in urban gas projects. Its main advantages are: high strength, good toughness, large load bearing stress, good impact resistance and tightness, good plasticity, easy welding and hot processing, thin wall thickness and metal saving. However, its corrosion resistance is poor and proper anti-corrosion measures are required. The steel pipes used in gas engineering are generally made of high quality low carbon steel (generally referred to as Q235B) or low alloy steel (generally referred to as Q345B). 　　1. Material selection of steel pipes 　　The steel pipes used for urban gas pipelines mainly include two types of seamless steel pipes and welded steel pipes. The strength of seamless steel tubes is very high, but limited by the production process and cost, it is generally small diameter steel pipes below DN200. There are many types of welded steel pipes, which can be divided into straight seam welded steel pipes (LSAW) and spiral seam welded s...

　　There is a certain relationship between the service life of the spiral steel pipe and the surface decarburization of the spiral pipe. If the surface is decarburized, the strength and wear resistance of the spiral steel pipe will be reduced, which directly affects the service life of the spiral steel pipe. If the decarburized layer on the spiral pipe is not cleaned, the surface layer hardness and wear resistance of the spiral steel pipe will be correspondingly reduced, and in the process of quenching, the surface of the workpiece will be caused by the change of the volume of the inner and outer layers. A crack is formed. 　　In order to solve the decarburization problem of the surface, the heat treatment process is mainly processed because the decarburization and the oxidation of the spiral steel pipe are simultaneously performed. Therefore, in the process of heat treatment, the spiral steel pipe should not be in contact with the air as much as possible. This can improve the phenomeno...