What Are The Connection Methods for Seamless Steel Pipes

1. Compression type: Insert the pipe into the nozzle of the pipe fitting, tighten it with a nut, and use spiral force to compress the casing at the nozzle through the sealing ring to act as a seal and complete the connection of the pipes.
2. Welding type: The end of the pipe is grooved, and the pipe is ring-welded by manual or automatic welding.
3. Flange type: perform annular argon arc welding on the flange and the piping, and tighten them with quick clamps or bolts to make the gasket between the flanges act as a seal and complete the piping connection.
4. Clamping type: Insert the pipe into the pipe fitting and use a special installation tool to clamp the pipe wall into a hexagonal shape, and the internal sealing ring also changes into a hexagonal shape.
5. Taper thread type: The external thread and the piping are subjected to circular argon arc welding, and the internal thread pipe fittings are connected with a tapered thread for sealing to complete the piping connection.

Extended information on seamless steel pipe:
1. The production process of seamless steel pipes can be divided into two types: cold drawing and hot rolling. The production process of cold-rolled seamless steel pipes is generally more complicated than hot-rolling. The tube blanks must first be subjected to three-roll continuous rolling and then extruded. After the sizing test, if there is no response crack on the surface, the round pipe will be cut by a cutting machine and cut into a blank of about one meter in length.
2. Enter the annealing process. Annealing requires pickling with an acidic liquid. When pickling, pay attention to whether there is a large amount of bubbling on the surface. If there is a large amount of bubbling, it means that the quality of the steel pipe cannot meet the corresponding standards.
3. The delivery state of hot-rolled seamless steel pipes is generally in the hot-rolled state after heat treatment. After passing the quality inspection, the hot-rolled seamless steel pipe must undergo strict manual selection by the staff. After the quality inspection, the surface must be oiled, followed by multiple cold-drawing experiments. After the hot-rolling treatment, a perforation experiment must be performed. , if the diameter of the perforation is too large, it needs to be straightened and corrected.
4. The outer diameter of hot-rolled seamless steel pipes is generally greater than 32mm, and the wall thickness is 2.5-200mm. The outer diameter of cold-rolled seamless steel pipes can be up to 6mm, and the wall thickness can be up to 0.25mm. The outer diameter of thin-walled pipes can be up to 5mm, and the wall thickness is less than 0.25mm. , cold rolling has higher dimensional accuracy than hot rolling.
5. General seamless steel pipes are made of hot-rolled or cold-rolled high-quality carbon structural steels such as 10, 20, 30, 35, 45, 16Mn, 5MnV and other low-alloy structural steels, or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other composite steels. of. Seamless pipes made of 10 and 20-grade low-carbon steel are mainly used for fluid transportation pipelines.
6. There are three ways to connect steel pipe threads: cylindrical internal threads inserted into cylindrical external threads, cylindrical internal threads inserted into conical external threads, and conical internal threads inserted into conical external threads. Among them, the latter two methods are more closely connected and are the most commonly used connection methods.
(1) Steel flange connection. Flanged loose flanges are generally used for pipes made of similar materials such as copper pipes, lead pipes, plastic pipes, etc. When flanging, different operating methods are selected according to different materials. The flanging must be smooth and must not have cracks or wrinkles.
(2) Threaded flange connection, using an internally threaded flange to connect to an externally threaded steel pipe. This type of flange is mostly made of cast iron and can be used to connect low-pressure pipelines.
(3) Welded flange connection. The flange and the steel pipe are welded. This flange connection is widely used. The welding method is: to select a pair of flanges and install them on the two connected pipe ends. If some equipment already has flanges, select flanges of the same specification set them on the flanges, and spot weld a little first. Correct the verticality, and finally weld the flange and the pipe firmly.