Steam pipe welding methods

Rendering using TIG backing, backing thickness not less than 3mm; often used when backing weld small flashlight to check whether or not the root of the weld penetration phenomenon; welding to "Positioning block" when the "positioning block "get rid of, and with a grinder pads worn away, leaving no scars and other traces of welding, and after the naked eye or with a low-power magnifier check to make sure no cracks and other defects, can continue welding; to improve the protective effect of argon fight tear a little bit at the end when welding aluminum foil tape; after bottoming end the self-test should be carefully and, if the defect should be immediately removed. After passing the self-test should be carried out under a layer of solder, to prevent cracks.

Fill and cover surface with SMAW, preheat temperature 200-300℃, inter-layer temperature 300℃-350℃; to reduce the amount of welding deformation should be symmetrical double welding; multi-pass welding joints should be staggered when 10- 15mm, each bead wire diameter is about control; swing width single pass welding electrodes used no more than four times the diameter; welders welding should be carefully observed in the base metal and welding consumables molten state, pay attention to the quality of the pool and closed arc to avoid crater cracks. Cover surface level fixed welded bead arrangement, at least three seam welding layer, the middle to have a "annealing Road" is appropriate, in order to facilitate improvement of weld metal microstructure and properties.

Notices of steam pipe welding: Do not play on the tube and test current arc; welding the pipe must not have drafts; welding rod, wire and hand tools are not allowed on the pipe; weld should be continuous weld end, must be taken in case of unexpected interruption after the hot, slow cooling, insulation and other measures should be carefully examined and then welded to ensure no cracks after only continue in accordance with the requirements of the welding process; the two can not be combined in a closed head, to avoid local overheating affect the welding quality. Each channel after each weld is completed, the application grinder or a wire brush to welding slag, spatter and other debris clean (with particular attention to the middle joint and bevel edge), after self-qualified before welding sub-layer.