Residual magnetism causes and impact on quality of welding in the construction and repair of gas pipelines welding job, sometimes magnetic blow phenomena affect the welding process. Forming a magnetic blow is the result of the presence of residual magnetism of the tube metal. Typically, magnetic sensors and magnetic remanence is divided into two processes. Magnetic induction pipe in the plant often produces links, such as: metal smelting, electromagnetic crane handling, steel parked in a strong magnetic field, magnetization complete non-destructive inspection method, steel supply line near the strong place, and so on. The magnetic assembly processes often produce during welding operations and the use of magnetic holder, fixture and took direct current welding pipes, such as: prolonged contact is connected to a DC power supply electric wire, bare wire segment, or short-circuit pipe welding clamp and the like. When welding with magnetic steel, often see the difficulties arc ignition, combustion undermine the stability of the arc, the arc deviation, liquid metal and slag melt from the weld pool spills in a magnetic field. In order to stabilize the welding process, to improve the quality of welded joints, magnetized steel before welding to be demagnetized. It should be noted, the steel pipe to be welded is difficult to achieve full demagnetization. So, when the remanence is insufficient to affect the quality of welding, it allows welding.
For degaussing before welding, we developed a single steel pipe and steel pipe butt at the degaussing process, including the following:
1. Determine the pipe size and orientation of the magnetic field left;
2. Select the degaussing method, system diagrams and technical means;
3. Use the selected method of degaussing butt welded steel pipe or at degaussing;
4. Check after remanence after degaussing, to see if it meets the requirements
Post time: Oct-11-2019