Demagnetization method of high-strength steel narrow gap welding groove

Abstract

The invention discloses a method for demagnetizing the groove of high-strength steel narrow gap welding. The groove is demagnetized several times, and the moving direction of the demagnetizer coil box is replaced after each demagnetization, and the demagnetization operation is completed when the residual magnetism of the groove drops below a certain value. The pulse demagnetization method is adopted, combined with spot welding before welding and installation The arc strike plate demagnetization process can effectively improve the demagnetization effect of large-sized workpieces. The demagnetizer has good portability and does not require the movement of the workpiece during application. It is especially suitable for demagnetization operations at the production site and has strong engineering adaptability.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a pre-weld demagnetization method for narrow-gap welding grooves of high-strength steel. Background technique [0002] Narrow gap metal arc welding can be divided into narrow gap submerged arc welding and narrow gap metal arc welding. It is a single (or double) multi-layer welding process using U-shaped or I-shaped grooves. , suitable for automatic welding of large thickness workpieces. For high-strength alloy steel base materials, due to their high content of alloying elements such as Ni and Cr, they are easily magnetized during rolling forming, storage and transportation, and welding groove processing. When welding this kind of high-strength steel with narrow gap technology, due to the narrow groove gap (generally only a few millimeters or more than ten millimeters), it often leads to a strong residual magnetic field between the two side walls of the groove, thereby destroyin...

AI Technical Summary

Problems solved by technology

If the longitudinal magnetic field strength is too small, the effect of counteracting the residual magnetism will not be good; if the longitudinal magnetic field strength is too large, the current density at the center of the weld will be too small, which will eventually have an adverse effect on the weld penetration and weld shape

This method offsets the influence of residual magnetism on the arc by applying an external longitudinal magnetic field, but does not fundamentally eliminate the residual magnetism of the groove. At the same time, the control requirements for the intensity of the external longitudinal magnetic field are also very high, and the engineering practicability is poor.

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