1.Metal phase
The full phase method is one of the main methods to distinguish between jointed steel pipes and seamless steel pipes. High-frequency electro-coal welding of steel pipes does not add welding materials, so the welding front of the welded steel pipe is very narrow. If the method of grinding and then stewing is used, the seam cannot be clearly seen. A high-frequency electric Yang coal joint is completed without heat treatment, which will cause the seam structure to be essentially different from the steel pipe parent material. When the ferrite and Wigmansite, base metal and weld zone structures are observed, , you can accurately identify welded steel pipes and seamless steel pipes.
2.Corrosion method
In the process of using the corrosion method to distinguish between welded steel pipes and seamless steel pipes, the seams of the processed welded steel pipes should be polished. After the grinding is completed, the traces of grinding should be visible, and then the end faces should be polished with sandpaper at the welds. And use 5% nitric acid alcohol solution to treat the end face. If an obvious weld appears, it can be proved that the steel pipe is a welded steel pipe.
3. Distinguish welded steel pipes and seamless steel pipes according to process
When differentiating between welded steel pipes and seamless steel pipes based on the manufacturing process, welded steel pipes are created through techniques like cold rolling and extrusion, involving the welding process., In addition, high-frequency, low-frequency arc welded pipes and resistance welded pipe processes are used to When welding, spiral pipe welding and straight seam pipe welding will be formed, which will form circular steel pipes, square steel pipes, oval steel pipes, triangular steel pipes, hexagonal steel pipes, ginger-shaped steel pipes, octagonal steel pipes, and even more complex ones. Steel Pipe.
4. Classify welded steel pipes and seamless steel pipes according to their uses
Welded steel pipes have higher bending and torsional strength and greater load-bearing capacity, so they are generally widely used in the manufacturing of mechanical parts. For example, oil drill pipes, automobile drive shafts, bicycle frames, and steel scaffolding used in construction are all made of welded steel pipes. However, seamless steel pipes can be used as pipelines for transporting fluids because they have a hollow cross-section and are long strips of steel with no seams around them.
Post time: Nov-10-2023