A welding process for improving the electrode life of resistance spot welding of electrogalvanized pre-phosphated steel sheets

By employing a three-stage welding process and dynamic pressure compensation technology, the problem of short electrode life in electro-galvanized pre-phosphated steel plates has been solved, resulting in a significant improvement in electrode life and stability in welding quality, thus meeting the high-efficiency production requirements of automobile manufacturing.

CN122400748APending Publication Date: 2026-07-17BENGANG STEEL PLATES CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
BENGANG STEEL PLATES CO LTD
Filing Date
2026-06-15
Publication Date
2026-07-17

AI Technical Summary

Technical Problem

Existing welding processes are not adapted to the surface characteristics of electro-galvanized pre-phosphated steel sheets, resulting in short electrode life. This is mainly due to the coupling effect between the high impedance of the phosphate film and the low melting point of the zinc layer, which causes problems such as current concentration, local overheating, and poor quality stability.

Method used

A three-stage welding process is adopted, which involves preheating with a pre-set slope current, main welding with a constant high current, and post-heating with a decaying current. Combined with dynamic electrode pressure compensation, the high-resistance pre-phosphating film is gently broken down, avoiding current impact and zinc layer spatter, promoting the solidification of the weld nugget, and inhibiting the copper-zinc alloying reaction.

Benefits of technology

It significantly extends electrode lifespan, ensures stable and reliable weld quality, reduces electrode replacement frequency, improves production efficiency, lowers costs, and meets automotive body welding quality requirements.

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Abstract

This invention discloses a welding process for improving the lifespan of resistance spot welding electrodes on electroplated galvanized pre-phosphated steel plates, relating to the field of metal material welding technology. The process includes: applying a current of a preset waveform to the electroplated galvanized pre-phosphated steel plate for welding, the preset waveform being a current waveform with a preset slope; after welding the electroplated galvanized pre-phosphated steel plate with the preset waveform current for a first preset time, applying a first preset value current to the electroplated galvanized pre-phosphated steel plate for welding. This invention employs a three-stage welding process, adapting to the surface characteristics of the electroplated galvanized pre-phosphated steel plate, gently breaking down the high-resistance pre-phosphated film, avoiding zinc layer spatter and electrode adhesion caused by current impact, and simultaneously utilizing the post-heating stage to accelerate the solidification of the weld nugget, evaporate residual zinc vapor from the electrode, and inhibit the copper-zinc alloying reaction, thus achieving the technical effect of significantly improving electrode lifespan and ensuring stable and reliable weld quality.
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