Spot weld nugget quality evaluation method

Abstract

The invention relates to a spot weld nugget quality evaluation method. The method comprises the following steps that: step 1, a spot weld sample is split along the center of the welding spot of the spot weld sample, and photographing is performed to obtain a nugget form picture; 2, a minimum fusion depth area connecting line, a defect allowable area connecting line and a maximum fusion depth areaconnecting line are drawn according to the obtained nugget form picture; and 3, whether the quality of a nugget is qualified or not is judged according to the drawn minimum nugget area connecting line, the defect allowable area connecting line and the maximum fusion depth area connecting line, if the section contour line of the nugget is located between the minimum fusion depth area connecting line and the maximum fusion depth area connecting line, and the defect of the nugget is located in the defect allowable area connecting line, the nugget is qualified, otherwise, the nugget is unqualified. With the method of the invention adopted, the quality of the spot weld nugget can be evaluated rapidly and visually. The method has the advantages of simplicity in operation and high working efficiency.

Description

technical field [0001] The invention relates to welding technology, in particular to a method for evaluating the quality of spot welding nuggets. Background technique [0002] Resistance spot welding is a method of using electric current through the weldment and the resistance heat generated at the contact as a heat source to locally heat the weldment, and at the same time pressurize for welding. The nugget formed by resistance spot welding plays a very important role in the welded structure, and its quality directly affects the reliability of the welded structure. factor. In the actual production and operation process, in order to ensure the quality of the nugget, it is proposed to use the relevant physical signals (dynamic resistance, electrode pressure, electrode displacement, acoustic emission signal, ultrasonic signal, X-ray) in the resistance spot welding process to control the nugget. The quality of the nugget is monitored, and the shape of the nugget in resistance ...

AI Technical Summary

Problems solved by technology

In the actual production and operation process, in order to ensure the quality of the nugget, it is proposed to analyze the nugget through the relevant physical signals (dynamic resistance, electrode pressure, electrode displacement, acoustic emission signal, ultrasonic signal, X-ray) in the process of resistance spot welding. The quality of the resistance spot welding nugget is not visible, and the quality parameters such as the diameter of the nugget cannot be truly inspected.

In order to ensure the quality of spot welding, in the welding procedure qualification test (to verify the stability of welding machine equipment and process parameters), it is an effective way to ensure the quality of the nugget by taking a certain proportion of spot welding samples for destructive inspection. The evaluation method only stipulates the size of nugget diameter, penetration depth, allowable defect location and maximum allowable size, etc., lacks a unified evaluation method for key parameters of nugget quality, and the evaluation method process is cumbersome, which is not conducive to operation

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