Residual stress is an important factor affecting the mechanical properties and service life of welded pipes. It arises due to non-uniform heating and cooling during the welding process.

Anti-corrosion steel pipe refers to a 3-layer structure polyolefin coated anti-corrosion steel pipe, which is a commonly used anti-corrosion pipeline in China. Let's take you to have a deeper understanding of anti-corrosion steel pipes. First, the anti-corrosion structure of anti-corrosion steel pipes and then the advantages of anti-corrosion steel pipes.

How does the thick-walled seamless steel pipe produce residual stress during cold drawing? The uneven deformation of the thick-walled seamless steel pipe under the additional stress cold drawing results in the residual stress after cold drawing.

Galvanized pipe is a galvanized pipe made by bending the strip steel or coil into a spiral shape and welding the inner and outer seams with double-sided submerged arc automatic welding. It is widely used in manufacturing industries such as construction, machinery, coal mining, chemical industry, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery, etc. Let's take a look at the advantages and disadvantages of galvanized pipes.

Straight seam steel pipes are a type of welded steel pipe. It refers to a steel pipe whose weld is parallel to the longitudinal direction of the steel pipe. After the hot-rolled steel coil is formed by a forming machine, the steel coil is deformed into a cylindrical shape. The high-frequency current skin effect and proximity effect or arc burning under the flux layer is used for welding, so that the edge of the tube blank is heated and melted under a certain extrusion pressure, melted, and finally cooled and formed. Yes. It is widely used in oil and gas transportation, low-pressure water-gas transportation, mine fluid transportation, belt conveyors, automobile drive shafts and other industries in petroleum, metallurgy, construction, coal mining, ports, machinery and other industries.

What are the specific processes for the heat treatment of seamless steel pipe? What precautions should be taken?

Double-sided submerged arc LSAW steel pipe is widely used in oil and gas pipeline projects, South-to-North Water Diversion Project, subway projects, West-to-East Gas Pipeline and other major projects. But do you know its production process flow?

Zinc is soluble in acids and alkalis, so it is called an amphoteric metal. Zinc is almost unchanged in dry air. In humid air, the zinc surface will generate a dense alkaline zinc carbonate film. In containing sulfur dioxide, hydrogen sulfide and marine atmosphere, zinc corrosion resistance is poor, especially in high temperature and high humidity containing organic acid atmosphere, zinc coating is very easy to be corroded.

Spiral steel pipe manufacturers produced by the spiral steel pipe varieties, in the loading and unloading process it is inevitable that steel pipe damage occurs, the specific matters are as follows:

Hot-dip galvanized steel pipe product standard name for the “low-pressure fluid transport with hot dip galvanized welded steel pipe”, is based on welded steel pipe inside and outside the hot-dip galvanized, so that the inside and outside walls of the steel pipe at the same time coated with zinc, greatly improving the corrosion performance of the steel pipe, up to the ordinary steel pipe about 20 times.

Straightening of LSAW steel pipe is an important process in the production of LSAW steel pipe. Especially for the higher quality requirements of API standard oil casing and oil and gas pipe, machinery and equipment special pipe, these kinds of steel pipe not only in the steel grade and weld quality has strict requirements, the straightness of the steel pipe also has high requirements.

After the steel pipe is descaled by shot blasting, before the next process of high-pressure electrostatic spraying of epoxy powder, the dust treatment device is used to carry out secondary treatment on the external surface of the steel pipe to remove the residual rust powder and dust on the external surface of the steel pipe, and the epoxy powder coating should be carried out within 4 hours, and if it takes more than 4 hours or the surface of the steel pipe appears to return to the rust, the surface must be re-treated. When the surface of steel pipe is treated with fine dust, the induced draft fan on the dust removing device should be started first, and then the dust removing motor should be started; if the production needs to be interrupted, the dust removing motor stop button should be pressed first, and then the induced draft fan should be stopped.

Seamless steel pipe welding process dissolved in the high temperature liquid metal gas in the cooling process will be in the form of bubbles overflow. If the slag viscosity of the seamless steel pipe is too large, the bubbles can not pass through the slag and are blocked near the surface of the weld metal to form pores. Steel pipes can be processed by adjusting the chemical composition of the flux and changing the viscosity of the slag.

After air drawing, the surface area of the outer surface of the seamless steel pipe increases, the surface area of the inner surface decreases, and a neutral layer is required between the inner and outer layers. After the deformation of the layer between the outer surface and the neutral layer, all the surface area increases, and the outer surface layer increases relatively more. After each layer between the neutral layer and the inner surface is deformed, the surface area decreases, while the inner surface decreases more. Divide both sides by D to obtain this formula.

Processing characteristics of seamless steel pipe fine casting: Since the shortening of seamless pipe steel pipe fine casting greatly exceeds the shortening of cast iron, in order to avoid the disadvantages of shrinkage and shrinkage of seamless pipe steel pipe, most of the casting process uses risers, cold irons and subsidies to complete the sequential condensation.