Resistance Spot Welding Current Staging for Oil-Contaminated Sheets
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Solution Overview
Problem
Excessive resistive heat generation due to oil on the surface of metal plates during resistance spot welding leads to electrode fusion and uneven nugget growth, compromising the welding process.
Innovation Solution
A resistance spot welding method that includes an oil removal step before nugget formation, utilizing controlled current patterns to remove surface oil and prevent excessive heat generation, ensuring accurate nugget formation without electrode fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If oil is applied to the metal plate surface for press working, then press workability is improved, but excessive resistive heat generation occurs during welding causing electrode fusion
Solution Approach 1:
The welding process is divided into multiple stages: a first energization stage at lower current to remove oil, followed by a second energization stage at higher current for nugget formation. This segmentation allows oil removal without excessive heat generation, preventing electrode fusion while maintaining press workability benefits.
Solution Approach 2:
Oil removal is performed as a preliminary action before main welding. The first energization stage removes oil from the metal plate surface prior to the main nugget formation process, preventing the harmful effects of oil during welding while preserving the press working advantages.
2Ease of manufacture
If oil remains on the surface during welding, then press workability benefits are maintained, but nugget growth becomes excessive in the energization direction
Solution Approach 1:
The welding process is divided into multiple stages: a first energization stage at lower current to remove oil, followed by a second energization stage at higher current for nugget formation. This segmentation allows oil removal without excessive heat generation, preventing electrode fusion while maintaining press workability benefits.
Solution Approach 2:
Oil removal is performed as a preliminary action before main welding. The first energization stage removes oil from the metal plate surface prior to the main nugget formation process, preventing the harmful effects of oil during welding while preserving the press working advantages.
3Productivity
If high current is applied directly for welding, then nugget formation is efficient, but electrode surface temperature increases causing fusion
Solution Approach 1:
The welding process is divided into multiple stages: a first energization stage at lower current to remove oil, followed by a second energization stage at higher current for nugget formation. This segmentation allows oil removal without excessive heat generation, preventing electrode fusion while maintaining press workability benefits.
Solution Approach 2:
Oil removal is performed as a preliminary action before main welding. The first energization stage removes oil from the metal plate surface prior to the main nugget formation process, preventing the harmful effects of oil during welding while preserving the press working advantages.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively suppresses electrode fusion and promotes controlled nugget growth, enhancing joint strength and reducing unnecessary energy consumption.
Implementation Method 1
excessive resistive heat generation due to the oil occurs during welding
Implementation Method 2
forming a nugget in an overlapped portion of the welding target material by energization between the pair of electrodes
Data Source
AI summary
A resistance spot welding method includes the steps of: removing at least part of oil on a surface of a welding target material by energization between a pair of electrodes; and after the oil removal step, forming a nugget in an overlapped portion of the welding target material by energization between the pair of electrodes.