Waterproof electrode, waterproof welding
Example: Water supply with steel pipe
Company Caoxi - central pumping station Huang She Lou 800 mm steel pipe leakage. The excavation, inspection found: weld welding position of about 600 - 700 mm cracking, the bottom of the crack width of nearly 15 mm. Pipe sewage for a reason can not be drained, the water depth of about 200 mm, the sewage at a long flow.
As the top of the water welding is different from the underwater wet welding, even with the T202 underwater electrode, the front overflow will break through the arc bubble, and the welding can not be carried out.For the commonly used electrode, the water will quickly cool the electrode coating, Condensation, no longer arc.
?In order to offset the water pressure from the leak and compensate for the heat loss of the welding water cooling, the use of small diameter electrode (2.5-3.2 mm) welding current 1.5-2 times larger than usual, short arc welding. From the direction of welding to be accurate, action to be fast, arc is not easy to use scratch method, easy to use touch method. Special attention, must not be convenient at the location of welding. In this case, when the weld is gradually reduced and concentrated in the lowest part of the welding position, the water is more urgent, welding will be more difficult (in general, the pipeline should be welded from the welding position.
1, the 12 mm of steel into the crack, the outer surface and the steel than the wall flat. , At the bottom of the pipe will be reinforced and pipe wall spot welding, then the steel into the crack by paragraph, every 50 mm on both sides of the spot welding. When the crack is too small can not break into the steel, for smaller steel bars, until the basic fill the cracks, control the gap to be welded less than 3 mm. Then the amount of water is clearly reduced, can be formally welded (it is necessary to wet gloves, clothes for dry, to prevent electric shock)
3, the more the more welding when the weld, the better the location, until the leak attributed to a little. At this time according to the size of the overflow pressure can be used in different ways: 1, with a tap into the cone of the welding plug, such as holes, temporarily blocked the hole, and then welding. 2, if the hole small, but the water more urgent. At this time may wish to elongate the arc, the use of electric home hot hole around the baked, the use of peripheral metal heat expansion, temporary swelling of the pores or simply hammer the hole immediately after the welding. Require this spot welding to be quick and accurate. When the droplets will be blocked after the hole, immediately off the arc. Action to be fast, so that the droplets have been blocked quickly cooled and completed welding. If the arc is too slow, then the back of the droplets have been re-melting, re-blowing under pressure. To be a little at the hole after the cooling, according to the need for re-welding.
2, start welding should be in the vicinity of the weld without water at the arc. After the arc short arc quickly arc to the weld, with the arc to withstand some of the overflow. In the edge of the weld to form a pool after the arc immediately lead to the steel, the two sides together and gradually welded up. Under normal circumstances should be continuous arc, once the welding stopped, the tip of the electrode will not be able to lead the original arc
Sewage equipment repair with time urgency, uncertainty, characteristics of labor intensity and so on. Requiring repair personnel in the shortest possible time to complete the repair and safe and efficient tasks, to ensure smooth flow. But in the process of repair the situation is changing, and sometimes seemingly simple process often have unexpected circumstances. Such as steel pipe repair, in general, as long as the welding can be, but sometimes for some reason the water inside the pipeline can not drain, which to welding and cutting to bring great difficulties
4, the first weld after the end of the weld there are a variety of defects. Such as: welding only in the wall surface, there is no penetration, welding weld when the inclusions and welding overflow quenching and melting of molten metal and so on. These defects in the original weld even if the re-welding, can not achieve the desired results. Therefore, in order to ensure the strength of the weld, should be added in the welding ribs, plate
