Steel tubes are an essential component in various industries, including construction, manufacturing, and transportation. These tubes are made using various processes depending on the desired properties, size, and shape. In general, steel tubes are made by forming steel into a cylindrical shape and then welding, rolling, or drawing the metal to the desired thickness and length. The following is a detailed description of the various processes used to make steel tubes:

1. Seamless Tube Manufacturing Process: Seamless tubes are made from a solid cylindrical billet by piercing it with a mandrel to create a hollow tube. The billet is then heated to the desired temperature and passed through a series of rollers to reduce the diameter and thickness of the tube. The tube is then cooled and cut to the desired length.

2. Welded Tube Manufacturing Process: Welded tubes are made by welding two pieces of steel together to create a seam. The steel is first rolled into a flat strip, and the edges are heated and pressed together to form a seam. The seam is then welded using a high-frequency electric current, laser, or other welding techniques. The tube is then cooled and cut to the desired length.

3. Electric Resistance Welded (ERW) Tube Manufacturing Process: ERW tubes are made by passing a flat strip of steel through a series of rollers to form a cylindrical shape. The edges of the strip are then heated and pressed together using electric resistance, creating a seam. The seam is then welded using high-frequency electric current, and the tube is cooled and cut to the desired length.

4. Drawn-Over-Mandrel (DOM) Tube Manufacturing Process: DOM tubes are made by drawing a solid steel bar through a die to create a hollow tube. The tube is then heated and passed through a series of rollers to reduce its diameter and thickness. The tube is then drawn over a mandrel to create its final shape, and the ends are cut to the desired length.

5. Cold-Drawn Seamless (CDS) Tube Manufacturing Process: CDS tubes are made by drawing a solid steel bar through a die to create a hollow tube. The tube is then cold-drawn through a series of dies to reduce its diameter and thickness. The tube is then cut to the desired length.

In conclusion, steel tubes are made using various manufacturing processes, including seamless, welded, electric resistance welded, drawn-over-mandrel, and cold-drawn seamless methods. The choice of manufacturing process depends on the desired properties, size, and shape of the tube.