Most of the currently used carbon steel welding arc welding. To improve the crack resistance of welded joints should be used in low-hydrogen electrodes. Individual circumstances, may also have calcium-based titanium and ilmenite acidic electrode, but this time the process should take strict measures, such as preheating before welding, to reduce the fusion ratio (reduced weld carbon content), etc.
Arc welding of carbon steel rod of choice when Special circumstances, can be used in chrome-nickel steel welding Stainless Steel Electrode, such as E0-19-10-16 (A102), E0-19-10-5 (A107), E1-23-13-16 (A302), E1-23-13-15 (A307), E2-26-21-16 (A402), E2-26-21-15 (A407), etc., due to the plasticity of austenitic weld metal sound, can reduce the welded joints stress, even if no preheating before welding weldment, heat affected zone can also be generated to avoid cold cracking.
In the process piping installation, welding is the primary means of connecting pipelines. Pipeline installation in the mouth of the weld because of its fixed operating conditions and environmental constraints become an important part of quality assurance. In a fixed population, the level of the fixed pipeline welding because it contains the Yang-welding, vertical welding, horizontal welding positions, such as call all-position Welding Electrode, so we fixed the horizontal pipe welding as the welding quality control Focus. The training of welders. The level of the fixed pipe welding pipe is fixed in space horizontal position, welding pipe does not move, welder welding along the seam. As the welding process, welding in different positions for each point, a level also includes the overhead position welding welding (weld the bottom), vertical welding (weld both sides), flat weld (weld at the top) three welding position. So the level of the weld ring is a kind of technique difficult welding techniques. Using manual GTAW for all-position pipe welding with arc stability and control models, both inside and outside the wall forming a good weld, easy to operate and so on. Operating points: prior to welding, the first tube end according to process requirements for the corresponding groove and clean up the groove edge of the 20-30mm. Counterpart of the top and bottom for tack welding, the correct operation of the method and welding torch using the angle to create a good line of sight, from the welding location from the overhead position welding welding, welding in flat position closing arc. From welding, with his left hand holding the torch of the first three hands, ring finger and small organizations to support the pipe wall as a fulcrum, the tungsten extreme head alignment groove roots, gently rotate the wrist to move closer to the Ministry of tungsten extreme tubing, Press the power switch on the torch, the use of high-frequency high-pressure device, triggering the arc ignition, arc after the arc is 2-3mm, press and hold the nozzle side of the welding torch parts for cyclical swing, and warm-up 2 - 3 seconds After filling began welding wire. Left to send wire welding, the molten metal should be sent to the groove root, so that both sides of the weld full shape. Arc welding process to take root and turn the heating wire groove ends of the methods of operation. Appropriate for the pipe weld gun nozzle tangent angle was 10-15 degrees, the angle should not be too large, or reduce the protective effect of argon gas, welding wire and welding torch angle is 90 degrees, should be observed during the welding process control groove penetration on both sides evenly. Semicircle on the flat weld seam welding position, should reduce the amount of filler metal, the weld flat, so flat after the semi-circular connectors, the first half circle in the welding had to be at the apex of 8mm extinction. Extinction before continuous feeding 2-3 drops of fill metal in order to avoid shrinkage, and argon to move one side of groove, and then turn off the arc. The welding position should be left circle in the right half circle from the welding position to put in about 4 - - 5mm. To ensure that the weld overlap, the left end of lap welding, the weld should be with the right half circle overlapping 4-5mm. After welding, the weld should be polished with polishing paste and remaining high until the metallic luster to grind up.