The material used for the stainless steel welding duct is steel plate or strip steel, which is divided into furnace welded pipe, electric welding (resistance welded) pipe and automatic arc welded pipe due to different welding processes. Due to the different welding forms, it is divided into straight seam welded pipe and spiral welded pipe. Because of its shape, it is divided into round welded pipes and special-shaped (square, flat, etc.) welded pipes.
The production process depends mainly on the product variety. From raw material to finished product, a series of processes are required. To complete these processes, various mechanical equipments and welding, electrical control and testing devices are required. These equipments and devices are required according to different process requirements. There are a variety of reasonable arrangements, the typical process of high-frequency welded pipe duct: unwinding - stripping leveling - head and tail shearing - strip butt welding - looper storage - forming - welding - removing burrs - sizing - flaw detection - flying cut ―Initial inspection-steel straightening-pipe section processing-hydraulic pressure test-inspection detection-printing and coating-finished products.
What are the processes for welding stainless steel tubes?
The spiral air duct process of stainless steel pipe welding is: preparation for installation → prefabrication processing → installation of dry pipe → installation of riser pipe → installation of branch pipe → pipeline anticorrosion and heat preservation → pipe flushing and pressure test.
Here are some of the steps to explain.
According to the drawings, draw sketches of the pipeline's shunt, pipe diameter, variable diameter, reserved nozzle and valve position, and mark it, then mark the actual accurate size. Pre-processing according to the drawings, grouping according to the pipe sections, and the valve can only be used after being tested.
2. Installation of the main pipe
(1) General pipe welding should use manual argon arc welding to ensure the cleaning inside the pipe; the cutting wheel cutting machine should be used when cutting.
(2) When the wall thickness of the pipe is not more than 4mm, the groove may not be opened. When welding, there shall be a gap of 2-3mm between the two pipes; when it is greater than 4mm, a single edge or V-shaped groove shall be opened. The mouth is about 65 degrees, and there should be a gap of 2-3 mm between the two tubes when welding.
(3) When the pipe group is opposite, the inner and outer walls should be flush, and the total amount of misaligned edges should not exceed 2 mm.
(4) When the pipeline is installed, the deviation per meter is not more than 1mm, and the total length deviation should be no more than 10mm.
(5) Pipe hangers and hangers should be made of angle steel for on-site processing to control the quality of the brackets.
3. Installation of riser
The risers are layered by number and installed in order. At least one pipe card should be set up for each floor when installing. After installation, use the line to hang straight.
4. Water test
Irrigation test requirements: the irrigation height should not be lower than the ground height, the time is 20 minutes, the liquid level does not drop, it means that the pipeline does not leak, it is qualified.
Passing ball test requirements: using a hard empty plastic ball, the ball diameter is 2/3 - 3 / 4 of the inner diameter of the pipe. Put the ball from the top and check it at the bottom. Pass the water inside the tube. If the test ball is unobstructed, it is acceptable.
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