A method for quantitative detection of nugget cracks using the energy equivalent of acoustic emission signals during resistance spot welding

An acoustic emission signal and resistance spot welding technology is applied in the field of quantitatively detecting nugget cracks by using the energy equivalent of acoustic emission signals in the resistance spot welding process, which can solve the problem that the nugget nucleation process cannot be directly observed and judge the quality of resistance spot welding solder joints. Difficulties, serious damage to the quality of solder joints, etc., to achieve the effects of low design and manufacturing costs, simple evaluation methods, and strong practicability
CN103675103BActive Publication Date: 2015-10-07CHONGQING UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN ยท China
Patent Type
Patents(China)
Current Assignee / Owner
CHONGQING UNIV OF TECH
Publication Date
2015-10-07

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Abstract

The invention provides a method for quantitative detection of nugget crack by using energy equivalent of an acoustic emission signal in a resistance spot-welding process. The method comprises the following steps: acquiring a structural load acoustic emission signal of the resistance spot-welding process in real time, drawing a dynamic oscillograph; extracting the acoustic emission signal of the crack; counting amplitude distribution; dividing the amplitude into a plurality of grades Mi, and accumulating according to ringing count Ni of the acoustic emission signals exceeding each amplitude grade, respectively, to obtain the log value log10Ni of the ringing count, so as to obtain a splattering distribution diagram; fitting a straight line to form a right triangle, calculating out the area, so as to obtain the energy equivalent of the corresponding resistance spot-welding nugget crack; setting an energy equivalent threshold value, determining an acoustic emission source to be a low-energy acoustic emission source when the energy equivalent is lower than the threshold value, and determining the acoustic emission source to a dangerous crack acoustic emission source when the energy equivalent is higher than the threshold value. Due to the adoption of the method, the grade and size of the resistance spot-welding nugget crack defect can be evaluated relatively exactly and quantitatively, and the rapid and nondestructive detection for the nugget crack is realized.
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Description

technical field

[0001] The invention relates to a nondestructive testing method for quantitatively detecting nugget cracks by using the energy equivalent of acoustic emission signals obtained by real-time detection in the resistance spot welding process, and is suitable for rapid detection of the nugget quality of resistance spot welding of commonly used metal sheet structural materials. Background technique

[0002] Resistance spot welding is a welding method widely used in automobile manufacturing, and there are about 3000-6000 resistance spot welding spots on a modern car. Therefore, the quality detection of resistance spot welding solder joints is very important. High-efficiency solder joint quality sensing and its detection and evaluation during the welding process are of great significance for optimizing the production process, improving production efficiency and welding quality. However, in the process of resistance spot welding, the nucleation process of the nugget c...

Claims

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