The neutral flame or slight carbonation flame of fast oxygen B should take excessive oxidation with oxygen flame will make aluminum strong oxidation if the acetylene excessive, will lead to weld porosity, the size of the tip size selection in accordance with the time. Thin pieces easy to burn, you want to select a smaller nozzle welding the same thickness of steel plate, welded aluminum thick pieces welded steel pieces due to substantial heat is about to select a large number of tip. Operating essentials: 1) the inclination of the nozzle and the wire nozzle inclination of the wire at 30 ° ~ 45 ° angle of about 40 ° -50 °, when welding thick rice I nozzle inclination angle should be at about 50 °, wire angle should be 40 °: When welding thin rice ~~ workpiece cold, 50 ° from the welding nozzle inclination should be big this final welding already at high temperature, inclination should be small, to avoid angle is too large, otherwise not blow open slag. 2) positioning welding: welding tack welding the relative position of the weldment fixed, you can use a the flame slightly larger than welding welding nozzle angle of 50 °. 3) welding direction: a thin aluminum should be left welding method, is conducive to the prevention of the molten bath overheating and heat-affected zone grain growth, the welding thickness greater than 5mm weldment right welding method, The right welding method allows high temperature Heating weldments to accelerate melting, more conducive to the observation of the molten pool and operation. 4) the operation of the nozzle and the wire: welding, the welding torch side of the forward side of the bounce up and down, when the operation to the bottom, the base material of the flame heated and melted, and by flame blowing force formed molten pool, when the movement to the upper flame heating wire, so that the ends melted to form a droplet, Thus, the material of the wire and the groove at the base material is periodically in a heat melted, thereby forming a weld, the wire feeder, the wire ends should be inserted into the molten pool front portion, and thereupon dragged outside the bath and mechanical action by the wire when applied to destroy the bath surface of the oxide film, and stirring the molten pool of metal, the impurities is discharged, and the droplet metal and molten bath would be a fusion. When a different thickness or different melting material welding, the flame should be pointing to a large thickness, a high melting point side, before welding should be a large thickness weldment preheated.