Diver underwater welding underwater operation

Diver underwater welding underwater operation

Diver underwater welding underwater operation

There are three types of underwater welding methods: dry method, wet method, and local dry method. This is a method of covering the welded object with a large gas chamber and welding by the welder in the gas chamber. Because the welding is carried out in a dry gas phase, the safety is very high. If the depth exceeds the range of air intrusion, the local oxygen pressure in the air environment increases, which can easily lead to the occurrence of Mars. Therefore, please use inert gas or semi inert gas in the gas chamber.

In the case of dry welding, welders must wear special high-temperature protective clothing. Compared with wet and local dry welding, dry welding is safe, but it has a greater limit of use and should not be widely addressed.

Partial dry welding is the process where the welder welds water and manually discharges the water around the welding area. The safety measures for underwater welding methods are similar to those for wet welding.

Due to the ongoing research on local dry methods, their use is not yet widespread. Wet welding is a welding process where the welder directly welds in water, rather than manually draining the water around the welding area. Electric arcs burn in water similarly to submerged arc welding, burning in bubbles. The coating placed on the welding rod during combustion forms a sleeve to stabilize the bubbles and arc. It is necessary to ensure stable combustion of the welding rod in water. A certain thickness of coating must be applied to the welding rod core, and the piston rod must be waterproofed by impregnating it with paraffin or other waterproof substances. Bubbles come from hydrogen, oxygen, water vapor, and other oxides generated by the combustion of the welding coating and the mixing of bubbles and smoke. In order to overcome the difficulties of arc initiation and stable arc initiation caused by water cooling and pressure, the arc initiation voltage must be higher than the arc initiation voltage in the atmosphere, and the arc current must be 15% to 20% higher than the welding current in the atmosphere.

Wet welding is more commonly used in underwater welding than dry and local dry welding, but its safety is inferior. Because water has conductivity, preventing electric shock has become one of the main reasons for wet underwater welding.