1）This process is suitable for the welding of various large steel structures 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 welding of thin and medium thickness plate parts.
1. Joint cleaning before welding requires that burrs, oil, rust and dirt affecting weld quality within 30mm 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, the object is thick, preheating measures should be adopted before welding, preheating temperature is 80℃~100℃, preheating range is 5 times of 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, groove Angle is 60°, blunt edge p is 0~1mm, assembly gap b is 0~1mm; When plate thickness difference ≥4. Depending on your welding position if it is full position welding, the plate is not thick, the current is between 100 and 200. Voltage BETWEEN 18 and 25. It depends on the performance of your welder and the wire used.
2）How should the welding current of the second welding technology be adjusted?
Two welding arc position: generally at the beginning of the welding end 15-20mm arc, from the end of the normal welding, this is based on the thermal ionization of gas away from the design, because the higher the temperature, the easier the thermal separation, arc easy to produce. Call it: preheating method arc. Render. Generally, the current coarse adjustment and fine adjustment 1 grade, 2 grade, fine adjustment has 10 grade and wire feeding speed is proportional to, the more crisp the welding sound, the better the welding effect of the specific current adjustment has a formula, familiar with the current can be large or small, see their own technique. To see the thickness of the welding base metal and adjust, the voltage is proportional to the current, the voltage is too high splash will be more, and too low, the welding wire and the base metal does not melt.
3）How to operate the technology of secondary protection welding
Left welding, current voltage with good, stable arc combustion, welding wire end with a slightly larger than the wire diameter of the small molten ball is appropriate. As for how thick the base material with how much current can only be mastered in practice. Two welding welding skills, welding torch low, the protection of the gas, generally used left and right swing or swing back and forth, forward welding. Keep your hands steady.
Matters needing attention:
1. The joints with vertical or inclined openings must be welded from bottom to top, and the thin plate butt and vertical fillet welding without opening openings can be welded downward; Flat, horizontal and vertical butt joints can be welded to the left.
2. When the wind speed is greater than 1m/s, take windproof measures.
3. A reasonable welding sequence must be selected according to the structure of the welder.
4. Arc-starting and arc extinguishing plates with appropriate size should be set at both ends of the butt joint.
5. Clean up the dirt and spatter in the hose regularly.
6. Groove groove seam, especially thick plate multi weld, welding wire swing on both sides of the groove should be slightly stopped, the thickness of each layer of serrated strip is not more than 4mm, in order to make the weld fusion good.
7. According to the diameter of the welding wire, choose the electrode of the welding wire correctly, and the length of the welding wire should be controlled within 10 times the diameter of the welding wire.
8. When welding the wire feeding hose, it must be pulled smoothly, not coiled, and the radius of the wire feeding hose should not be less than 150mm. The remaining impure gas in the air supply hose should be discharged before welding.
9. The aperture of the conductive nozzle increases after wear, resulting in unstable welding. It is necessary to replace the conductive nozzle.
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