Multi-physical-field auxiliary dissimilar metal material welding method

Abstract

A multi-physical-field auxiliary dissimilar metal material welding method comprises the following steps of (1) removing dirt on to-be-welded surfaces of two different metal materials, cleaning and preheating after drying; (2) heating through an external heating source under the atmospheric environment, or nitrogen or argon atmosphere to enable a base metal or filling materials at a joint position to be melted into liquid metal, meanwhile applying double physical fields of ultrasonic waves and a magnetic field and obtaining a composite welding seam after the liquid metal at the joint position is cooled and solidified; (3) obtaining a particle reinforced welding seam after the liquid metal at the welding seam is solidified and cooled to be in the indoor temperature. The multi-physical-field auxiliary dissimilar metal material welding method has the advantages of effectively controlling interface reaction and intensifying flowing of the liquid metal by applying the ultrasonic waves and the magnetic field, obtaining the composite welding seam with intermetallic compound particles being enhanced, being beneficial to integral combination of a welded joint, improving mechanical property of the welded joint, refining welding seam crystal particles, reducing residual stress, reducing toxic and side effects to persons and harmful effects to an aluminum steel bonding interface from brazing flux and being beneficial to environmental protection.

Description

technical field [0001] The invention belongs to the field of welding technology, in particular to a multi-physics field-assisted welding method for dissimilar metal materials. Background technique [0002] Dissimilar material welding and joining technology is a material forming method that realizes firm metallurgical bonding at the interface of two or more metals with different physical, chemical and mechanical properties. The base metal still maintains its original characteristics, which is much better than using a single metal. Therefore, the method of welding and connecting dissimilar materials has always been widely valued. Aluminum, steel, titanium and copper are common metals, and their welding and connection are widely used in power generation equipment, automobiles, ships, steel transportation, nuclear energy, machinery, aerospace, petroleum, chemical industry, etc. [0003] The welding and joining methods of dissimilar metals mainly include brazing, fusion welding ...

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Problems solved by technology

[0007] The main problems in the above process are: during the welding process, the reaction of dissimilar metals is rapid, violent, and unavoidable, and the resulting brittle intermetallic compounds are difficult to withstand the stress, which is easy to cause cracking and reduces the mechanical properties of the welded joint.

At present, the idea of ​​reducing the impact of intermetallic compounds on dissimilar materials is generally to adjust welding parameters, optimize the process, reduce heat input, and then reduce the formation of intermetallic compounds, but dissimilar metals react quickly, and it is difficult to completely avoid them.

Dissimilar materials have poor mutual solubility. When melting and welding, the liquid phase separates, and when cooling and crystallizing, the weld composition is uneven and cracks are prone to occur; the thermal expansion coefficient is different, and the weld is prone to stress, causing welding deformation and crack initiation; the thermal conductivity is different. , the crystallization condition deteriorates, and it is easy to cause grain coarsening; the secondary oxide film on the surface of the metal material grows rapidly, which may cause inclusions, cracks, and affect the interface bonding; the cleaning process of the metal surface before welding is cumbersome, and the use of flux during the welding process will cause harm to personnel. Toxic and side effects, it is difficult to clean up the flux after welding, and it is easy to have adverse effects on the bonding interface

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