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.

The appearance of the steel pipe shows regular folding in the form of triangular, double-seam straight line, single-seam straight line or irregular sheet folding.

When performing straight seam steel pipe cutting, there are several important considerations to know and follow to ensure quality and safety of the cut. The following are some of the precautions

LSAW steel pipe is a kind of welded steel pipe. Steel pipe parallel to the longitudinal direction of the steel pipe. After the hot rolled steel coil is formed by forming machine, the said coil is converted into a cylinder and welded by using high frequency current skin effect and proximity effect or arc combustion under the flux layer, so that the edge of the pipe billet is heated, melted, fused and cooled to form under a certain extrusion pressure, correct, petroleum, metallurgy, construction, coal mine, port, machinery, and other industries are widely used in the transportation of oil and gas, low-pressure water and gas transportation, mine fluid transportation , belt conveyor, automobile drive shaft and other industries.

First, the premise should be polished However, the galvanized layer of the weld must be polished off, otherwise it will produce bubbles, trachoma, false welds and so on. It will also make the weld brittle and less rigid.

Spiral pipe, also known as spiral steel pipe or spiral welded pipe, is a low carbon structural steel or low alloy structural steel steel strip according to a certain angle of the helix (called molding angle) rolled into a billet, and then welded the pipe joints made of it, it can be used to produce large diameter steel pipe with a narrower strip.

Steel pipe can be divided into two categories according to the production method: seamless steel pipe and seamed steel pipe. Seamed steel pipe is referred to as straight seam pipe. 1.Seamless steel pipe can be divided into two categories according to the production method: hot rolled seamless pipe, cold drawn pipe, precision steel pipe, hot expanded pipe, cold rolled pipe and extruded pipe. Seamless steel pipe is made of high-quality carbon steel or alloy steel, hot rolled, cold rolled (drawn).

1, tungsten can improve the red hardness and thermal strength of spiral steel pipe, and can improve the wear resistance of spiral steel pipe. 2, silicon; it can improve the hardness of spiral steel pipe, but plasticity and toughness decline, electrician spiral steel pipe contains a certain amount of silicon, can improve the soft magnetic properties.

Welding current In LSAW pipe multi-wire submerged arc welding, all the wire welding current increases, the height of the weld will increase, but different wires increase to different degrees. Usually the first wire of the welding current in all the wire in the largest, it changes relative to other wires will cause a large change in the height of the residual, and the middle of the wire relative to the last wire to be a little stronger. Similarly, the first wire welding current on the weld depth of fusion also has the greatest impact, the middle wire as a weld filler on the weld depth of fusion is relatively small, the last wire has almost no effect on this. This point in the automation forum has also seen related reports. Therefore, in the preparation of multi-wire submerged arc welding welding process, should be the first wire welding current is the largest, followed by the middle, the last one is the smallest.

First, how to categorize spiral steel pipe according to the working method? Hot expanded steel pipe pipeline irrigation system based on the work in the method can be divided into portable, semi-fixed and fixed.

Seamless steel pipe hot dip coating surface in the solidification of the coating metal crystallization pattern, this crystallization pattern of galvanized seamless pipe is particularly obvious, showing the appearance of beautiful zinc crystals, and thus become an important feature of the appearance of hot-dip galvanized seamless pipe, usually referred to as this crystallization pattern for the “zinc flower”. When the galvanizing solution contains other metal impurities, zinc flower is produced. Zinc flower size and shape depends on the type and amount of impurities contained in the galvanizing solution, common impurities are lead, aluminum, antimony, bismuth, tin and other metals.

(A) rolling groove weld cracking 1, will be the mouth of the pressure groove part of the inner wall of the weld rib grinding, reduce the rolling groove resistance. 2, adjust the axis of the steel pipe and rolling groove equipment, and require the steel pipe and rolling groove equipment level. 3, adjust the pressure groove speed, pressure groove molding length can not exceed the provisions of the uniform, slow application of force.