Gas-Shielded Arc Welding Wire Composition for Stable Overhead 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 welding wire with specific chemical compositions and a controlled production process, including molten steel smelting, refining, steel billet casting, temperature-controlled heating, temperature-controlled rolling, and Stelmor slow cooling, to ensure proper fluidity and stability of the weld metal, with elements like C, Si, Mn, S, Ni, Cr, and Mo optimized to improve strength, toughness, and forming property.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding wires are used for all-position welding, then the welding process can be completed, but the 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 applies parameter changes by optimizing the chemical composition parameters of the welding wire, specifically controlling the content of deoxidizing elements (Si: 0.5-1.0%, Mn: 1.4-1.8%, P: ≤0.0015%, S: 0.013-0.1%) and adjusting the liquidus-solidus temperature difference to 25-45°C. These parameter adjustments modify the physical and chemical properties of the weld metal, improving its fluidity and solidification characteristics to prevent downward flow and improve forming property.
Solution Approach 2:
The patent employs composite material principles by creating a multi-element alloy system that combines Fe, C, Si, Mn, P, S, Ni, Cr, and Mo in specific proportions. This composite material approach allows the welding wire to achieve a balance between strength, toughness, and forming property, where the interaction of multiple elements produces synergistic effects that prevent weld metal dropout while maintaining mechanical properties.
2Manufacturing precision
If the liquidus-solidus temperature difference is increased to improve weld metal solidification control, then the forming property improves, but the welding process becomes more sensitive to parameter variations
Solution Approach 1:
The patent optimizes the liquidus-solidus temperature difference to a specific range of 25-45°C through careful adjustment of chemical composition parameters. This controlled parameter change provides sufficient solidification control to improve forming property while avoiding excessive sensitivity to welding parameter variations. The deoxidizing element content is precisely controlled to achieve this optimal temperature difference range.
3Strength
If the content of deoxidizing elements is increased to improve the strength and toughness of weld metal, then the mechanical property improves, but the fluidity of molten drop decreases, affecting the forming property
Solution Approach 1:
The patent resolves this contradiction by optimizing the content parameters of deoxidizing elements to specific ranges rather than simply increasing them. Si is controlled at 0.5-1.0%, Mn at 1.4-1.8%, P at ≤0.0015%, and S at 0.013-0.1%. These optimized parameters achieve sufficient strength and toughness while maintaining adequate fluidity for good forming property. The synergistic interaction of multiple elements in these specific proportions balances mechanical properties and forming characteristics.
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 achieves a weld metal with good fluidity, quick solidification, and uniform welded seams, enhancing the tensile strength and impact energy of the weld metal, ensuring a smooth and attractive weld bead during all-position welding.
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
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, which can effectively improve the strength of a welded seam
Implementation Method 3
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 4
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
Implementation Method 5
Ni is an element for improving the strength and low-temperature impact toughness of the welded seam, and Ni can refine a structure to promote formation of the acicular ferrite, thereby playing an important strengthening role in the weld metal
Implementation Method 6
Cr can increase the content of the acicular ferrite in the welded seam, thereby improving the strength and low-temperature toughness of the welded seam
Implementation Method 7
Mo can lower a phase-transition temperature, inhibit generation of the proeutectoid ferrite, promote transformation of the acicular ferrite, and increase a proportion of the acicular ferrite
Implementation Method 8
in combination with restrictions on the liquidus temperature and the solidus temperature of the welding wire, melting point and solidifying point intervals of the welding wire are controlled, so as to control a solidification speed of the weld metal
Data Source
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],