The seamless steel tube is produced according to different processes. It is a steel pipe parallel to the longitudinal direction of the steel pipe, and is usually divided into a metric electric welded steel pipe, an electric welding thin wall pipe, a transformer cooling oil pipe and the like. Seamless steel tubes have different use values ​​and functions in use, and need to be used and welded according to the corresponding methods. In the welding process, the use and attention are different, and it is necessary to carry out production and processing according to a certain production process.
The seamless high-frequency welded steel pipe has the characteristics of relatively simple processing, rapid and continuous production, and the process in production is simple and convenient, and is produced and processed according to the corresponding process. Seamless steel pipes are widely used in civil construction, petrochemical, light industry and other sectors. They are used to transport low-pressure fluids or make various engineering components and light industrial products. They play an important role and value in different industries and show good characteristics. And performance. The following describes the production and processing process of seamless steel pipe products, and matters that should be paid attention to during use.
1. Production process of seamless steel pipe
The seamless steel pipe is a high-speed welding unit that winds a long strip of a certain specification into a round tubular shape and seamlessly welds it into a steel pipe, which has a good welding process and technology. When welding seamless steel pipe, the shape of the steel pipe can be round or square or irregular. The choice of steel pipe depends on the sizing rolling after welding. The material of the welded steel pipe, the material of the steel pipe is different, the main production and The processing technology will also be different. The processing materials to be noted are low carbon steel and low alloy steel or other steel with σs ≤ 300N/mm2 and σs ≤ 500N/mm2. The welding technology of seamless steel pipe is relatively simple, and it is produced and processed through the corresponding process technology to ensure the important role and value in use and reflect good value.
2. High-frequency welding technology of seamless steel pipe
The high-frequency welding of seamless steel tubes is based on the principle of electromagnetic induction and the skin effect of alternating charge in the conductor, the proximity effect and the eddy current effect, so that the steel at the edge of the weld is locally heated to a molten state, and is pressed by a roller to make butt welding. The seam realizes the intergranular bonding to achieve the purpose of weld welding. The high frequency welding is an induction welding (or pressure contact welding), which does not require weld filler, no welding splash, narrow welding heat affected zone, and beautiful welding appearance. The welding machinery has good performance and so on, so it is widely used in the production of steel pipes.
The high-frequency welding of seamless steel tubes is to use the skin effect and the proximity effect of alternating current. After the steel (strip) is rolled and formed, a circular blank with a broken section is formed, which is near the center of the induction coil in the tube blank. Rotating one or a group of resistors (magnet bars), the impedance forming an electromagnetic induction circuit at the opening of the tube blank, and under the effect of the skin effect and the proximity effect, a strong and concentrated thermal effect is generated at the edge of the opening of the tube blank, so that the welding The edge of the seam is rapidly heated until the temperature required for welding is pressed by the pressure roller, and the molten metal realizes intergranular bonding, and after cooling, a firm butt weld is formed.
The welding technology of seamless steel pipe needs to be grasped and well controlled during welding to ensure that the welded steel pipe has no quality and performance problems and quality, and plays an important role and value in use.