In the pipe from the top of the arc, from top to bottom all-position welding technology, welding speed method, weld appearance, good welding quality, welding materials can be saved, reducing labor intensity is a common hand can not be more widely than now Applied to large-diameter long-distance pipe welding in the lower welding of large-diameter thin-walled tube construction of all power status has a certain promotional value.

Black steel pipe is made from steel that has not been galvanised and is called black because of the dark coloured iron-oxide scale formed on its surface. it is used in the oil and petroleum industries to transport large quantities of oil and for the distribution of gas into homes. It is used in transporting water and gas in both rural and urban areas as we as for conduits that protect electrical wiring. It is also used for delivering high pressure steam and air.

The use of epoxy powder coating in foreign countries have 30 years of history, due to a wide range of sources of raw materials, production methods are simple, cheap, good performance, do not pollute the environment, long life, is a good anti-corrosion coating. Petroleum Institute of Building Technology Corrosion in the oil pipeline in China, the successful development of the epoxy powder to fill the domestic pipeline anti-corrosion coating anti-corrosion paint blank. The coating has excellent chemical resistance, good mechanical properties, high electrical insulation properties and good toughness. Corrosion test Predict the life of the coating, intact storage of paint, oil, gas, water pipes, life expectancy of up to 15 years; make sewage and mixed water pipe coating life of up to 5-7 years. The pipe industry's construction methods, the most widely used static thermal spraying method. According to the data, the coating requirements for epoxy powder coatings are also different due to the thickness of the media delivered. Domestic oil, gas, water, sewage and other corrosive medium containing corrosion pipe is the best thick coating. Electrostatic spraying thick coating, spray thickness up to 250 ~ 350 / a, the maximum thickness of up to 500, ~ (n) electrostatic powder moraine coating is a surface treatment of solid powder, it has the equipment is simple, easy to operate, The process is simple, not subject to the size of the workpiece and other advantages.

According to the spiral submerged arc welded pipe corrosion mechanism, has put forward a variety of protective measures, this protection can basically be divided into the following types:

In the long-distance pipeline construction, the pipeline accounts for a large proportion, generally 35% to 40% of the total investment pipeline project management. How to choose a reasonable price, excellent performance of the pipeline is particularly important, a reasonable choice of pipeline construction investment savings, the construction of the pipeline system and safe operation has a very important impact. Natural gas pipe straight seam high-frequency resistance welded steel pipe, spiral submerged arc welded pipe, LSAW steel pipe.

The main difference between seamless steel pipe and welded pipe is the molding process. Generally welded steel pipe, such as water pipes, are usually bent and welded together by a flat plate, after which you can find a seam; the diameter is usually a spiral weld.

In the pipe from the top of the arc, from top to bottom all-position welding technology, welding speed method, weld appearance, good welding quality, welding materials can be saved, reducing labor intensity is a common hand can not be more widely than now Applied to large-diameter long-distance pipe welding in the lower welding of large-diameter thin-walled tube construction of all power status has a certain promotional value.

Welding method is under the conditions of welding materials, according to the design requirements of the welding components, and can meet the requirements of the scheduled service. The four factors are affected by the welding material, welding, the type of part and the usage requirements.

Steel pipe hardness and tensile strength

Effect of remanence on welding quality and its influence Gas pipeline construction and repair welding operations, sometimes appear blowing phenomenon, affecting the welding process. The formation of a magnetic strike is due to the presence of metal residual magnetism in the pipe. Usually, the magnetic induction and remanence are divided into two processes. Magnetically-induced plants tend to produce tube links such as metal smelting, handling using electromagnetic cranes, tube parking in a strong magnetic field, non-destructive testing after magnetization, and placing the tube close to the power cord and so strongly. Magneto-electric welding often occurs during the process. When assembling and using the magnetic retainer, the fixture and the DC welding pipe are connected to each other. For example, a long contact is connected to a DC power cable, a bare wire section or a short-circuit pipe welding fixture.

3PE corrosion-resistant steel pipe buried pipe life is crucial, the same material, pipe buried in the ground for decades and some non-corrosive, leaks in a few years. Because they use different outer coating.

Classification and Production Methods of Welded Steel Pipe

Eddy current testing features are as follows: Advantages of eddy current testing 1, When test, the coil does not require contact with the workpiece, but also without the coupling medium, so the detection speed.

The following hs code apply to all kinds of steel pipe products, such as seamless pipe, welded pipe(erw pipe, ssaw pipe, lsaw pipe), stainless steel pipe, pipe fittings, etc.

Steel pipes are ubiquitous and can be found in underground and residential walls, laboratories, and commercial and industrial structures. Pipes transport fluids, including water, natural gas, waste and air. There are three manufacturing methods for the production of steel pipes. The seamless steel pipe is produced by extrusion die. The welded steel pipe is produced by rolling the steel plate into the pipe and welding.

Due to the strong bending ability of carbon steel pipe factory, so in recent years, the stadium building roof truss, beam, column, the steel structure housing, with the development of steel structure manufacturing industry in the construction of more and more use of steel structure, household appliances, furniture, plumbing, HVAC, gas, transportation and agriculture equipment the manufacturing industry, coal, oil and gas exploitation of underground resources, gun, air and space rockets, artillery, missile etc.. Iron and steel can not be separated, so the development of the national economy on the pipeline is closely related to the living standard of the people.

Galvanized steel surface coated with a layer of zinc is generally low carbon steel, galvanized layer is generally 20um thick. At 419 ° C, the melting point of zinc is about 908 ° C. During welding, zinc is melted into the liquid that floats on the surface of the cell or the root of the weld. Zinc is more soluble in iron and the zinc corrosion solution will enter the weld metal along the grain boundaries, forming a "low melting point of liquid metal embrittlement." At the same time, brittle intermetallics of zinc and iron may form, and these brittle phases, Tensile stress cracks in the weld metal plasticity decreased. If the weld, fillet weld is the most easy to penetrate the crack. When welding galvanized steel, the zinc layer oxidizes, melts, evaporates and even volatilizes white smoke and steam at the bevel surface and edges at the arc heat, easily causing the weld pores.

Hot galvanized is the addition of some auxiliary material to the molten zinc at a high temperature, and then attaching the zinc-dip bath metal structure to the metal member on the zinc layer. Hot-dip galvanizing with anti-corrosion ability, coating adhesion, good hardness and so on. Cold galvanized is the use of the degreased workpiece electrolysis device, the pickling component is zinc salt solution, and connected to the cathode electrolysis device; zinc electrolysis device placed on the front of the connecting plate, the power supply is reversed, moving from the positive to negative direction current The use of it to deposit a layer of zinc on the workpiece.

galvanized zinc sheet appears on the surface, that is, those rough small particles do not polish, which not only affect the appearance of small particles, but also affect the use. This is because the bottom of the dregs is too agitated and the surface temperature of the galvanized sheet is too high because of the good affinity with the aluminum, aluminum and zinc in the zinc solution, except for the bottom ash float process Together, attached to the galvanized sheet surface. For example, the bottom ash is often treated to maintain the cleanliness of the galvanized steel. The temperature of the zinc-plating solution is not too high and is maintained at a suitable temperature of 440 to 450 degrees Celsius. Liquid zinc aluminum content is not high, maintained at about 0.1% is appropriate, but also pay attention to inventory will increase oxidation, etc. In short, as long as the strict production of zinc, or can be eliminated.

The advantages of galvanized pipe are as follows: 1, Galvanized pipe can be protected by hot galvanized surface, and the inner cavity of the tube or any other coating angle difficult to enter, deepen the zinc easily covered to the top, so that the entire galvanized pipe is protected.

Low-carbon steel pipe generally rolled into angle, channel, I-beam, steel, steel or steel. It is widely used in various building components, containers, huts, stoves and agricultural machinery. Low-carbon high-quality steel rolled into thin-sheet production car cab, hood and other deep wahsed products. It can also be rolled into strips for dmanding production of machine parts. Mild steel is generally not used after heat treatment, when the carbon content by carburizing or cyanindation of 0.15% or more, can be used for shafts, bushings, sprockets and other parts of the surface temperature requirements, wear-resistant.