Welding technology of membrane water wall
Circulating fluidized bed boiler is a new power station boiler, which is widely used in small and medium-sized power stations instead of pulverized coal boiler. It has the advantages of energy saving, less pollution, low cost and can burn many kinds of coal, especially low-quality coal. At present, it is strongly advocated to replace pulverized coal boiler. However, because the water wall adopts membrane water wall, it increases many difficulties in the ground assembly of rows of pipes, the spatial position is horizontal fixation and obstacles, and the welding process has great changes. The welding process of membrane water wall of yg75 / 3.82-M1 boiler is discussed as follows.
welding technology
1. Welding method
Manual argon tungsten arc welding shall be used for backing and manual arc welding for covering. The material of the pipe is 20g and the specification is ф 60 * 5mm, pipe spacing is 20mm. Tig-j50 welding wire and J422 welding rod are adopted, with specifications of ф 2.5mm, argon purity not less than 99.95%, the welding machine adopts gs-400ss silicon rectifier welding machine.
2. Welding preparation
1) Remove the oil, rust, paint and oxide scale, grind the metal luster within 10-15mm on the inner and outer sides of the groove, and the unilateral groove is 30-35 degrees.
2) Reliable windproof measures must be taken at the argon arc welding site, and both ends of the pipe shall be blocked with pipe plugs to prevent ventilation, so as not to affect the argon protection effect.
3) According to the drawing, the weld gap is 1mm. Considering the actual effect, the gap is 2-3mm, and the lower part can be larger and the upper part can be smaller. The tack welding position is one point at the top and one point at the bottom, and the length is 20mm.
3. Welding parameters
Main welding parameters: wire diameter ф 2.5mm, welding current 75-85a, arc voltage 20-24v, gas flow 6-8l / min, DC power supply, electrode connected to positive electrode, ce-20 tungsten electrode, nozzle diameter 10mm, tungsten electrode extension length 6-8mm. Electrode diameter ф 2.5mm, current 75-85a.
Shanghai duomu Industrial Co., Ltd. is a high-tech industry specializing in power supply development, in which welding power supply is my key project. The developed series of welding machines have reached or exceeded the international advanced level, are deeply recognized by customers, and have a wide customer base and popularity. The products are specialized in welding precision parts and thin plates, surfacing of valves, rollers and picks, welding repair of molds and mechanical shafts, etc. they have been widely used in many fields such as electronics and electrical appliances, coal mining machinery, aerospace and so on.
