Gas-Shielded Arc Welding Wire Composition for Slag-Free Coating
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Solution Overview
Problem
Current welding wires for gas-shielded arc welding generate excessive spatter and require a separate slag removal step, leading to coating defects and reduced corrosion resistance, especially in thin steel sheets used in vehicle underbody parts.
Innovation Solution
A wire composition with optimized levels of C, Si, Ti, Mn, and N is used to minimize spatter generation and ensure a thin, adhesive slag forms uniformly on the weld, allowing for excellent electrodeposition coatability without post-weld slag removal, improving bead shape and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodeposition coating is performed after welding, then corrosion resistance is improved, but coating defects occur on weld slag and coating film peeling happens during traveling
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the welding wire (C: 0.01-0.10 mass%, Si: 0.05-0.55 mass%, Mn: 1.60-2.40 mass%, Ti: 0.05-0.25 mass%, Al: 0.003-0.10 mass%). By optimizing these compositional parameters, the slag's adhesive properties are improved, enabling the electrodeposition coating film to adhere properly to the weld surface without peeling during subsequent traveling, thus resolving the contradiction between corrosion resistance and coating quality.
2Reliability
If slag removal step is added to ensure reliability, then coating defects are prevented, but production steps and costs increase
Solution Approach 1:
The patent applies the self-service principle by designing a welding wire that automatically produces slag with optimal adhesive properties through its specific chemical composition. The slag self-adheres to the weld bead without requiring external intervention or removal steps, allowing direct electrodeposition coating application. This eliminates the need for separate slag removal operations while ensuring reliable coating adhesion, thus maintaining productivity while achieving coating reliability.
3Ease of operation
If spatter generation is reduced for better workability, then welding quality improves, but specific compositional adjustments are required
Solution Approach 1:
The patent applies composite materials principle by creating a multi-element alloy composition combining C, Si, Mn, Ti, and Al in specific proportions. This composite wire composition synergistically reduces spatter generation during welding while maintaining good slag adhesion properties. The combination of multiple elements works together to improve workability without requiring overly complex compositional adjustments, as the elements complement each other's functions.
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 solution reduces spatter, eliminates the need for slag removal, enhances electrodeposition coatability, and maintains a smooth bead shape, thereby improving the corrosion resistance and strength of welds in thin steel sheets.
Implementation Method 1
wire for gas-shielded arc welding
Implementation Method 2
electrodeposition coating after arc welding is adopted as a method of protecting underbody parts
Data Source
Figure 1~2
AI summary
An amount of spatter generated during welding is small, a step such as removal of the slag after welding is unnecessary, and a weld portion having excellent electrodeposition coatability and a good shape of the bead can be obtained. A wire for gas-shielded arc welding includes, based on a total mass of the wire: C: 0.01 mass% or more and 0.10 mass% or less, Si: 0.05 mass% or more and 0.55 mass% or less, Mn: 1.60 mass% or more and 2.40 mass% or less, Ti: 0.05 mass% or more and 0.25 mass% or less, Cu: 0.01 mass% or more and 0.30 mass% or less, S: 0.001 mass% or more and 0.020 mass% or less, N: 0.0045 mass% or more and 0.0150 mass% or less, Al: 0.10 mass% or less, and P: 0.025 mass% or less, with the remainder being Fe and inevitable impurities, and the following relationship is satisfied: 0.1 ≤ [Ti]/[Si] ≤ 3.0, wherein [Si] is the content of Si (mass%) based on the total mass of the wire and [Ti] is the content of Ti (mass%) based on the total mass of the wire.