Pulsed Resistance Spot Welding for Fast Nugget Growth With Less Spatter
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Solution Overview
Problem
Existing resistance spot welding methods face challenges in growing a nugget to a desired size within a short time while effectively suppressing spatter generation, particularly when using high current energization for extended periods or low current energization for prolonged times.
Innovation Solution
A resistance spot welding method involving a pre-energization step with pulsation energization that alternates high and low current energizations at short intervals, followed by a main energization step that includes slope or constant current energization, to control the alloy layer and nugget growth efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high current energization is performed for a long time, then a nugget grows rapidly, but spatter is generated
Solution Approach 1:
The patent applies periodic action by alternating between high current energization and low current energization in a cyclic manner during the pre-energization step. This periodic switching allows the nugget to grow rapidly during high current phases while the low current phases suppress spatter generation, thereby resolving the contradiction between fast nugget growth and spatter control
2Object-generated harmful factors
If only low current energization is performed, then spatter is suppressed, but growing a nugget to a desired size requires too much time
Solution Approach 1:
The patent uses periodic action by implementing alternating high current and low current energization phases. The low current phases suppress spatter while the high current phases accelerate nugget growth, achieving both spatter suppression and reduced welding time that would not be possible with continuous low current energization alone
3Productivity
If high current energization is used, then a nugget grows quickly, but temperature rises sharply causing spatter
Solution Approach 1:
The patent applies periodic action by switching between high current energization (which promotes rapid nugget growth) and low current energization (which allows temperature to stabilize and prevents sharp rises). This periodic modulation of current intensity enables fast nugget growth while controlling temperature excursions that would otherwise cause spatter
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
This approach allows for the creation of a nugget with a desired size within a short time while significantly reducing spatter generation, by managing temperature rise and alloy layer formation effectively.
Implementation Method 1
resistance spot welding method includes: a pre-energization step of performing energization on metal plates as a welding target
Implementation Method 2
The pre-energization step includes a pulsation energization that repeatedly alternates a high current energization and a low current energization at intervals of less than 10 ms
Implementation Method 3
a main energization step of performing energization after the pre-energization step
Data Source
AI summary
A resistance spot welding method includes a pre-energization step of performing energization on metal plates as a welding target until an alloy layer diameter reaches a predetermined target diameter, the alloy layer being formed at an outer periphery of a nugget in a welded part of the metal plates and including a constituent material of a plating layer of the metal plate and a base metal of the metal plate; and a main energization step of performing energization after the pre-energization step. The pre-energization step includes a pulsation energization that repeatedly alternates a high current energization and a low current energization, the high current energization being performed at a current higher than a predetermined threshold current, the low current energization being performed at a current lower than or equal to the threshold current. The pulsation energization includes performing the high current energization two times or more.