Gas-Shielded Arc Weld Composition for E-Coat Corrosion Resistance
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Solution Overview
Problem
The challenge is to provide a gas-shielded arc welded member with excellent electrodeposition coating corrosion resistance for welded portions in the automobile industry, while ensuring economic efficiency and addressing issues related to stress concentration, corrosion, and productivity in high-strength steel parts.
Innovation Solution
The solution involves controlling the chemical composition of the welded portion, specifically limiting elements like C, Si, Mn, P, S, Cr, Mo, Al, Ni, Ti, and optionally including Nb, V, Zr, B, and Cu, to ensure that the Si and Mn contents satisfy specific relational expressions, thereby reducing silicon-based oxide slag and improving corrosion resistance and electrodeposition coating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If gas-shielded arc welding is performed on plated steel, then welding strength is achieved, but pore defects occur due to zinc vaporization
Solution Approach 1:
The patent changes the chemical composition parameters of the welding wire, specifically controlling Si content at 0.01-2.00 wt% and Mn content at 1.00-5.00 wt%, along with their ratio Si/Mn of 0.05-2.00. These parameter adjustments modify the welding process characteristics to suppress zinc vaporization and reduce pore formation while maintaining welding strength.
Solution Approach 2:
The patent uses a composite welding wire composition combining multiple elements (Si, Mn, Cr, Mo, Al, Ni, Ti, Cu, B, Nb, V, Zr) in specific proportions. This composite material approach creates a synergistic effect where the combination of elements provides both strength and reduced porosity, resolving the contradiction between welding strength and quality.
2Ease of manufacture
If general uncoated steel is used for welding, then welding is achieved, but slag occurs in the welding bead causing painting defects
Solution Approach 1:
The patent adjusts the chemical composition parameters of the welding wire, particularly controlling Si content at 0.01-2.00 wt% and Mn content at 1.00-5.00 wt%, with a specific Si/Mn ratio of 0.05-2.00. These parameter changes modify slag formation characteristics to reduce slag generation and improve surface quality for painting, while maintaining ease of welding.
3Strength
If plated steel materials are used for weight reduction, then material strength increases, but corrosion resistance at welded portions decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the welding wire, specifically controlling Si content at 0.01-2.00 wt%, Mn content at 1.00-5.00 wt%, and their ratio Si/Mn of 0.05-2.00. These parameter adjustments optimize the welding process to preserve the plated layer at the welded portion, thereby maintaining corrosion resistance while using high-strength plated steel materials.
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 effectively provides a welded member with excellent electrodeposition coating corrosion resistance, even without pickling treatment, and ensures performance and cost competitiveness in the era of electric vehicles, by reducing corrosion mass loss and improving the durability of welded portions.
Implementation Method 1
gas-shielded arc welding of plated steel
Implementation Method 2
welded portion includes... C: 0.001 to 0.30%, Si: 1.00% or less (excluding 0%)
Data Source
AI summary
Provided is a welded member including a welded portion with excellent electrodeposition coating properties and corrosion resistance. The present disclosure may provide a welding member including a gas shielded arc welded portion capable of securing excellent electrodeposition coating properties and corrosion resistance for a welded portion in the automobile industry.