Oxygen flame gas welding operation
Manual Pen,Tattoo Makeup Pen,Comestic Tool Kiay Trade Cosmetology Co., Ltd. , http://www.chinatattoomachines.com
November 17 16:04:53, 2018
(1) Preheating If the heat welding method is used, there are many preheating methods, and the workpiece can be slowly heated to 600 to 650°C by using an electric furnace, an oil furnace, a floor furnace, or the like. (2) Welding rods and welding powders There are two grades of cast iron rods commonly used for gas welding. QHT-1 (including C3.3~3.9%, Si3; .0~3.8%, Mn0.5~0.8%, S≤0.08% , P0.15 ~ 0.4%) for hot or cold welding thin pieces; QTH-2 (including C3.3 ~ 3.9%, Si3.8 ~ 4.5%, Mn0.5 ~ 0.8%, S ≤ 0.08%, P0 .15~0.4%) is suitable for cold welding. The unified grade of gas welding powder is powder 201. Can also be homemade welding, commonly used are: borax 56%, 22% sodium carbonate, potassium carbonate 22%; borax 50%, 50% soda ash; dehydrated borax 100%. (3) Flames and Torches Castings Gas welding often uses neutral or weakly carbonized flames. The oxidizing flame is available at the bottom of the defect and at the opening of the bevel, and the weld can be slowly cooled by the carbonization flame at the end of the welding. If the wall thickness of the casting is 20-50mm, the diameter of the welding nozzle hole is 3mm, the oxygen pressure is 6kg/cm2; when the wall thickness of the weldment is less than 20mm, the welding torch with the nozzle diameter of 2mm is selected, and the oxygen pressure is 4 Kg/cm2. (4) Welding process 1 Before the welding, the oil and oxide around the defects must be removed. The sanding can be used to expose the substrate to the original metallic luster. And then in the welding site open groove, the general groove depth of the weldment wall thickness of 2/3, the groove angle of 70 to 120 degrees. If it is hot welding, it needs to be warmed up. Pay attention to the preheating temperature of 600-650°C, and do not exceed 700°C. 2 welding. Firstly, the bottom of the groove and the circumference of the weld seam are heated by the flame. When the matrix metal begins to melt, a small amount of solder powder is added to thoroughly clean the surface of the substrate, effectively removing impurities until pure molten iron appears in the molten pool. During the filling process, care must be taken to ensure that the metal of the base metal is filled with the electrode metal. When a white bright spot (SiO2) is found in the bath, the filler metal should be stopped, the appropriate amount of solder powder should be added, and the inclusions should be removed with a welding rod before continuing the welding. Filling requires continuous welding, once filling the groove, welding near the end, should start shaping, so that the weld slightly higher than the surface of the weldment, and scrape off the surface layer containing more impurities to facilitate post-welding processing.