Welding process of straight seam welded steel pipe

The straight seam steel pipe adopts a small specification model, which can avoid crack and deformation. The welding current is 20% lower than that of high carbon steel. In order to ensure the ignition of electric arc, DC reverse connection is adopted. In multi-layer welding, the temperature shall be controlled. After welding, forced water cooling can be adopted without arc outside the groove. The wire joints shall be connected correctly, and the weld deformation can only be corrected by cold drawing.

 Arc welding: arc welding is used for straight seam steel pipe, with good high temperature performance, high connection index, good welding forming, no slag shell and smooth surface. Argon arc welding is used for welding 0.5 ~ 3mm stainless steel plate. The composition of electrode is usually the same as that of welding part. Pure argon in industrial production is usually used to maintain steam. In order to prevent transverse shaking during welding, It needs to speed up as much as possible. Argon arc welding can be used for plates with a thickness of more than 3mm. It has high arc welding output rate, small welding deformation, good corrosion resistance and easy operation.

Gas welding: gas welding is convenient and has strong cooperation ability. It is used for welding indoor space parts. For some straight seam welded steel pipe components, such as thin plate structure and thin-wall pipe, gas welding can sometimes be applied without corrosion resistance. In order to avoid overheating, the ultrasonic mold is generally smaller than electric welding to weld high carbon steel of the same thickness. The gas cutting flame adopts neutral flame, The left electric welding method is adopted for electric welding. The inclination between the top of the welding gun and the welding material is 40 ° ~ 50 °. The welding gun shall not swing horizontally along the molten pool with the flame. The welding shall be faster and the fracture shall be reduced as much as possible.

Submerged arc welding: it is suitable for medium level thin, left and right straight seam welded steel pipes. The output rate of submerged arc welding is high, but it is easy to cause segregation and residue of aluminum alloy elements.

Hand welding: hand welding is a common welding process. The arc length depends on the gap between metal electrode and steel sheet. In addition, when used as arc carrier, metal electrode is the raw material for welding.

The welding process of straight seam steel pipe is simple and can be used for electric welding of all raw materials. It has good adaptability. Most DC welding machines can adopt tungsten argon arc welding. In electrode welding, if the gap between electrode and steel is changed, the arc length can also be changed.

The metal electrode is composed of aluminum alloy or aluminum alloy core wire and electrode coating. In addition to stabilizing the arc, the coating is also used to maintain gas damage, stainless steel electrode and titanium electrode, which depends on the thickness and composition of the skin. The titanium electrode is easy to weld, smooth and beautiful. In addition, the electrode is easy to be removed, the electrode storage time is long, and it needs to be baked again.