Method for reducing residual stress of heterogeneous brazed joint

Abstract

The invention belongs to the technical field of welding, and relates to a method for reducing residual stress of a heterogeneous brazed joint. According to the method, when the temperature of the brazed joint is reduced to a certain temperature, the temperature of the joint is reduced and the residual stress of the joint is reduced in the circulating process by firstly carrying out heating treatment, generating micro plastic deformation and micro precipitation, reducing the residual stress, carrying out cooling again, generating the residual stress and then reducing the stress by raising the temperature, so that the temperature of the joint is reduced and the residual stress of the joint is reduced in the circulating process. According to the cryogenic circulation treatment, through heating and cooling circulation between (0.1-0.4) T and-(75-150) DEG C, movable dislocation in the tissue is eliminated through uneven deformation generated by the thermal expansion and cold contraction effect, fixed dislocation entanglement is achieved, value is increased, and residual stress in the brazed joint tissue is reduced.

Description

technical field [0001] The invention belongs to the technical field of welding, and relates to a method for reducing residual stress of a heterogeneous brazing joint. Background technique [0002] After brazing of the dissimilar material brazing joint, the dissimilar material with a small shrinkage will prevent the dissimilar material with a large shrinkage from continuing to shrink. At this time, the dissimilar material with a large shrinkage will be subjected to tensile stress along the brazing interface direction. The dissimilar materials with small shrinkage will be subjected to compressive stress along the brazing interface direction, so the brazed joint is prone to generate large residual stress on the interface after welding, resulting in cracks or other types of defects in the joint, thereby reducing the bonding strength and service life. [0003] Furthermore, during the cooling process of the joint, the uneven deformation and phase transformation deformation caused...

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Problems solved by technology

[0002] After brazing of heterogeneous material brazing joints is completed, the heterogeneous material with small shrinkage will prevent the heterogeneous material with large shrinkage from continuing to shrink. At this time, the heterogeneous material with large shrinkage will be subjected to tensile stress along the direction of the brazing interface. Dissimilar materials with small shrinkage will be subjected to compressive stress along the direction of the brazed interface, so brazed joints are prone to generate large residual stress on the interface after welding, resulting in cracks or other types of defects in the joint, thereby reducing the bonding strength and service life

[0003] Furthermore, during the cooling process of the joint, the uneven deformation and phase transformation deformation caused by uneven cooling and different linear expansion coefficients will generate residual stress, which greatly reduces the strength and stress fracture resistance of the joint, so it is urgent to propose a method that can A New Cooling Treatment Method for Reducing Residual Stress of Joints and Improving Comprehensive Performance of Joints

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