What are the preparations for secondary welding of 16Mn seamless steel pipes?

1. Before welding, the cleaning of joints requires that the burrs, oil stains, scales and scales that affect the quality of the weld within 30 mm on both sides of the groove must be cleaned.

2. When the construction environment temperature is below zero or the carbon equivalent of steel is greater than 0.41%, and the structural rigidity is too large, pre-welding measures should be adopted when the object is thick. The pre-heating temperature is 80 ℃ ~ 100 ℃, and the pre-heating range is 5 times the plate thickness, but not less than 100mm.

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

4. The smooth wire feeding and gas flow of the CO2 welding machine 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), stop using it.

6. Adjust the specifications according to different welding workpieces and welding positions. The usual welding specifications can use the following formula: V=0.04I+16 (allowable error ±1.5V)

If the 16Mn seamless steel pipe is welded well, its performance and advantages will be greatly improved. Sometimes it will get twice the result with half the effort, but if the welding is not good, it is prone to problems. Sometimes if the situation is serious, accidents will occur!


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