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Preparation before welding aluminum welding

Addtime:2014��10��24��  Times:
Processing 1 groove 
     Thickness of 3 mm or less in time to open groove butt welds, just at the back of the weld down a 0. 5 ~ 1 mm angle can be, it is a good gas emissions and avoid the back of the groove. Back chamfering impact on whether the weld. Aluminum alloy plate bevel angle larger than the steel. I generally use a single slope of 55 ° bevel, bevel bilateral using 35 ° bevel on each side. This allows to improve the accessibility of the welding, and can reduce the generation probability of lack of fusion defects. 
     For thick T-joints in HV or HY fittings required to fill slope estuary, plus a fillet weld, the weld thickness not less than the total size of S T. 
Before welding cleanup 
     Welding aluminum requires the cleanest preparation work, or drop their resistance to corrosion, and prone to porosity. Welding aluminum welding steel should be used to thoroughly distinction. Welded steel tools have been used, use non-welded aluminum. Trimming region oxide film impurities, as far as possible the use of stainless steel brush or cleaned with acetone. Grinding wheel can not be used, because the use of grinding wheel will make the surface of the oxide film fused welding consumables, but not really removed. And if the use of a hard grinding wheels, wherein the impurities into the weld, resulting in thermal cracking. Further, since the Al2O3 film and the bulk will be regenerated in a very short time, the oxide film in order to influence as little as possible the weld should be cleaned immediately after completion of welding. 
3 preheat temperature and surface temperature control 
     When the thickness within 8 mm thick plate welding, preheating should be carried out before welding, preheating temperature control between 80 ℃ ~ 120 ℃, interpass temperature control between 60 ℃ ~ 100 ℃. Preheat temperature is too high, in addition to the harsh operating environment, there are likely to impact on the performance of aluminum alloy, appear joints soften, forming undesirable phenomena such as weld appearance. Increase in temperature will make the inter-layer aluminum welding hot cracking generation probability. 
4. reasonable choice specification parameters 
     Physical and chemical properties of aluminum alloy and steel far, want to test and determine the welding parameters according to the welding characteristics of aluminum alloys. 
The thermal conductivity of aluminum itself large (about four times stronger than steel), fast heat dissipation. Thus, the welding speed in the same, the amount of heat input than when the aluminum welding heat input amount 2 to 4 times the steel when welded. If the heat input is insufficient, inadequate or incomplete fusion penetration problems, particularly in the weld start position prone. 
5 wire feed speed should be appropriate to increase 
     Wire feed speed is closely related to the current and voltage specification parameters, and matched. When the welding current increase, wire feed speed should be increased accordingly. 
6 to select the welding speed 
     For thin weld seam in order to avoid overheating, generally smaller welding current and welding speeds; For thick welds to the weld and weld fusion fully sufficient gas to escape, welding using a larger welding current and a slower speed. 
7 torch angle selection 
     In the welding direction, torch angle is generally controlled at about 90 °, is too large and too small will cause welding defects. Too torch angle caused by insufficient gas porosity; angle is too small to make the liquid aluminum is also possible to reach the front arc, the arc can not produce a direct effect on the weld lack of fusion.