Degreasing method for stainless steel pipes and fittings:
1. Degreasing method of stainless steel pipe
Since the stainless steel pipe only needs to be degreased, in addition to the degreasing method of the carbon steel pipe mentioned above, the large-diameter pipe can also be degreased by wiping. It is not suitable to use cotton yarn when degreasing by wiping method, and use cloth, silk, glass fiber fabric, etc. whose fibers are not easy to fall off. Longer pipes can be scrubbed with a clean wire tie with a two-way drag to remove oil on the inner wall of the pipe. After degreasing, the surface of the degreasing part must be carefully inspected. It is strictly forbidden for the fibers of the organic fabric to fall into and adhere to the surface of the degreasing part. After the inspection is passed, the nozzle should be blocked immediately.
2. Degreasing method of stainless steel pipe fittings and valves
According to the volume of the largest valve, use a steel plate to make a self-made degreasing container (or simply refit it with an iron drum that holds carbon tetrachloride). After removing the rust and dirt from the inner wall, wipe it with a white cloth. Wipe the stainless steel pipe fittings and valves that need to be degreased with a dry white cloth (note: the white cloth should be bought with better quality, without losing the wool), and string them with iron wire or thin steel wire rope and put them in the production container.
Inject carbon tetrachloride into the container, and soak the stainless steel pipe fittings and valves. Do not overfill when filling, and it is best to keep the liquid level at a distance of 200mm from the top of the container to prevent carbon tetrachloride from overflowing and causing pollution or personal injury. Because carbon tetrachloride is toxic and easy to volatilize, the operator should stand in the upwind position when injecting liquid to prevent poisoning by inhaling carbon tetrachloride. Then cover the container, soak it for 1h to 2h, take out the pipe fittings and valves, dry the inner and outer surfaces of the pipe fittings and valves with a silk cloth, and then air-dry them naturally. After the inspection is qualified, the pipe fittings and valves are packaged and sealed with plastic sheeting.
Before degreasing, the valve should be ground and tested to pass the pressure test, then disassembled into parts to remove rust and other debris, and soaked in carbon tetrachloride solvent for 1h to 1.5h. Bolts and metal washers are degreased in the same way.
Valve housings that are inconvenient to soak can be wiped off. When degreasing non-metallic gaskets, immerse them in carbon tetrachloride solvent for 1.5h to 2h, then take them out and hang them in an air circulation place or in a ventilation device to dry them one by one until there is no solvent smell. For the asbestos filler in the valve, it can be burned at a temperature of about 300 ℃ for 2 min to 3 min (smoky flame shall not be used), and then impregnated with the specified coating.