Identification Method Of Welded Steel Pipe And Seamless Steel Pipe (Down)

3. Discrimination of welded steel pipe and seamless steel pipe according to process

In the process of distinguishing welded steel pipes and seamless steel pipes according to the process, welded steel pipes are welded according to cold rolling, extrusion and other processes. In addition, when welding steel pipes using high-frequency, low-frequency arc welded pipes and resistance welded pipes, The formation of spiral pipe welding and straight seam pipe welding will form round steel pipes, square steel pipes, oval steel pipes, triangular steel pipes, hexagonal steel pipes, diamond steel pipes, octagonal steel pipes, and even more complicated steel pipes.

Galvanized Welded Steel Pipe

In short, different shapes of steel pipes will be formed by different processes, so that welded steel pipes and seamless steel pipes can be clearly distinguished. However, in the process of distinguishing water seamless steel pipe according to the process, it is mainly identified according to the hot rolling and cold rolling treatment methods, and there are also two main forms of seamless steel pipes, which are hot rolled seamless steel pipes and Cold rolled seamless steel tube. Hot-rolled seamless steel pipes are formed by perforation, rolling and other processes, especially seamless steel pipes with large diameters and thicknesses are welded by this process; cold-drawn tubes are cold-drawn by using tube blanks, and the strength of the material is lower , But its appearance and internal control surface are smooth.

4. Classification of welded steel pipes and seamless steel pipes by application galvanized welded steel pipe has higher bending and torsional strength and more load-bearing capacity, so it is generally widely used in the manufacture of mechanical parts. For example, oil drill rods, automobile transmission shafts, bicycle frames, and steel scaffolding used in building construction are made of welded steel pipes. However, the seamless steel pipe can be used as a pipeline for conveying fluid because it has a hollow cross-section and there is no strip of steel around the periphery. For example, it can be used as a pipeline to transport oil, natural gas, gas, and water. In addition, the seamless steel pipe has a relatively low bending strength, so it is generally widely used in low and medium pressure boiler superheated steam pipes, boiling water pipes and locomotive boiler superheated steam pipes. In short, through the classification of applications, welded steel pipes and seamless steel pipes can be clearly identified.

In order to ensure the higher quality of China's engineering construction, we must distinguish between welded steel pipes and seamless steel pipes, then use appropriate steel pipe for construction. In the process of distinguishing welded steel pipes and seamless steel pipes, metallographic methods and corrosion methods can be used to inspect the welds by observing the structure and welds, and finally accurately distinguish them. At the same time, two types of steel pipes can also be distinguished according to their properties and uses, and then reasonable steel pipes are selected for construction.