Gas-Shielded Arc Welding Wire Composition for Stable All-Position Beads
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Solution Overview
Problem
During all-position welding, weld metal at the 12 o'clock position flows downwards and falls, resulting in poor forming property and uneven weld beads.
Innovation Solution
A steel wire rod for gas shielded arc welding with specific chemical compositions and a controlled production process, including molten steel smelting, refining, casting, temperature-controlled heating, rolling, and slow cooling, to ensure proper fluidity and stability of the weld metal, with elements like C, Si, Mn, S, Ni, Cr, and Mo to enhance strength and toughness, and control liquidus and solidus temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional welding wire is used for all-position welding, then welding can be performed, but weld metal at the 12 o'clock position flows downwards and falls, resulting in poor forming property and uneven weld beads
Solution Approach 1:
The patent changes the chemical composition parameters of the welding wire, specifically controlling C (0.03-0.08%), Si (0.5-1.0%), Mn (1.4-1.8%), S (0.013-0.1%), and other elements within precise ranges. It also controls the liquidus- solidus temperature difference (25-45°C) by adjusting compositional parameters, which fundamentally alters the molten metal's fluidity characteristics to prevent downward flow at the 12 o'clock position while maintaining good forming property.
Solution Approach 2:
The patent utilizes phase transition characteristics of the welding wire by controlling the liquidus and solidus temperatures within a narrow difference (25-45°C). This controlled phase transition behavior during welding allows the molten metal to maintain stability, solidify properly, and form uniform weld beads without unwanted flow or dropping, directly addressing the forming property issue.
2Manufacturing precision
If sulfur content is reduced to improve weld metal quality, then weld quality improves, but desulfurization cost increases
Solution Approach 1:
The patent optimizes the sulfur content parameter to a specific range (0.013-0.1%) rather than simply minimizing it. This balanced parameter setting achieves sufficient weld metal quality while avoiding excessive desulfurization costs, representing an optimal trade-off point determined through systematic parameter optimization.
Solution Approach 2:
The patent utilizes sulfur's beneficial role in controlling molten metal surface tension and fluidity. By maintaining sulfur within the optimal range, the molten metal achieves appropriate fluidity for good forming property without requiring excessive desulfurization, thereby reducing processing costs while maintaining weld quality.
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 ensures a uniform and smooth welded seam surface and attractive weld bead shape during all-position welding, with a tensile strength of 770 MPa or above and impact energy of 98 J or above at -40°C, while reducing desulfurization costs and improving the welding process performance.
Implementation Method 1
C, as one of important elements in the steel wire rod of a welding wire, can reduce the average size of austenite grains, reduce proeutectoid ferrite, and increase acicular ferrite, thereby effectively improving the strength and hardness of weld metal
Implementation Method 2
C, as one of important elements in the steel wire rod of a welding wire, can reduce the average size of austenite grains, reduce proeutectoid ferrite, and increase acicular ferrite
Implementation Method 3
Si, as a main deoxidizing element and strengthening element in the steel wire rod of a welding wire, is mainly subjected to solution treatment in austenite and ferrite
Implementation Method 4
Si, as a main deoxidizing element and strengthening element in the steel wire rod of a welding wire, is mainly subjected to solution treatment in austenite and ferrite, thereby playing a solution treatment strengthening role
Implementation Method 5
Mn, as a deoxidizing element in a welding process, forms an oxide in a deoxidizing process, which can improve the strength and toughness of the welded seam
Implementation Method 6
S, with a content in a range of 0.013%-0.1%, can improve surface activity of the molten drop, and increase fluidity of the weld metal
Data Source
Figure 1~2
AI summary
The present invention discloses a welding wire for gas shielded arc welding, and a steel wire rod of a welding wire for gas shielded arc welding and a production method therefor. Chemical components of the steel wire rod of a welding wire for gas shielded arc welding include, in mass percentage, 0.03%-0.08% of C, 0.5%-1.0% of Si, 1.4%-1.8% of Mn, 0.013%-0.1% of S, less than or equal to 0.0015% of P, less than or equal to 0.8% of Ni, less than or equal to 0.4% of Cr, less than or equal to 0.4% of Mo, and the balance of Fe and inevitable impurities; and a liquidus temperature TL=1537-88[C]-8[Si]-5[Mn]-30[P]-25[S], a solidus temperature Ts=1536-415[C]-12[Si]-6.8[Mn]-125[P]-184[S], and 25°C≤TL-TS≤45°C.