The carbon dioxide welding process is suitable for all kinds of large steel structure engineering welding of low carbon steel and low alloy high strength steel. It has high welding productivity, good crack resistance, small welding deformation, large deformation range, and can be used for thin plate and medium plate. welding.

1. Cleaning of joints before welding requires burrs, oil stains, rust and dirt, and scales that affect the weld quality within 30 mm of both sides of the groove.

2. When the construction environment temperature is lower than zero or the carbon equivalent of the steel is more than 0.41%, and the structural rigidity is too large, the preheating measures should be adopted before the object is thick. The preheating temperature is 80 °C ~ 100 °C, and the preheating range is 5 times the thickness of the board, but not less than 100mm.

3. When the thickness of the workpiece is more than 6mm, in order to ensure the penetration strength, the V-shaped or X-shaped groove should be used at the butt joint edge of the plate. The groove angle is 60°, the blunt edge p is 0~1mm, and the assembly gap b is 0. ~1mm; when the difference in thickness is ≥4mm, the butt edge of the thicker plate should be chamfered, as shown in the figure:

4. The wire feeding of the CO2 welder and the gas flow should be carefully checked before welding.

5. If bottled gas is used, it should be drained and purified, and the gas pressure should be checked. If it is lower than 9.8×10.5PQ (10kgf/mm2), it should be stopped.

6. According to different welding workpiece and welding position adjustment specifications, the general welding specification can use the following formula: V=0.04I+16 (allowable error ±1.5V)

Welding materials

1. The purity of CO2 gas is 99.5%; the water content is not more than 0.1%; the carbon content is not more than 0.1%. 2. Welding wire grade low carbon steel and high strength low alloy steel important structure welding H08Mn2SiAH08Mn2SiA low carbon steel general structure welding using H08MnSi. Copper plating on the surface of the wire does not allow rust spots to exist.