Low-Hydrogen Coated Electrode Design for Welding Workability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional low-hydrogen coated electrodes for high Cr ferrite heat-resistant steel suffer from electrode burning during welding, leading to decreased arc stability, increased spatter, and poor weld quality, with existing techniques failing to adequately address these issues.
Innovation Solution
A low-hydrogen coated electrode with a specific composition and design, including a core wire and covering material with optimized C, Si, Mn, Cr, Mo, and Fe content, and a covering material with Ca carbonate, metal fluoride, and SiO2, which enhances electrode burning resistance and coatability, and improves the quality of the weld metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional covering material containing metal carbonate (30-60 wt%) is used to ensure good welding workability, then welding workability is improved, but electrode burning occurs during welding leading to decreased arc stability and increased spatter
Solution Approach 1:
The patent changes the chemical composition parameters of the covering material by replacing metal carbonates with metal fluorosulfonates, adjusting the chemical nature of the flux components to prevent electrode burning while maintaining welding workability
Solution Approach 2:
The patent uses a composite covering material containing metal fluorosulfonate, metal fluoride, and other flux components in specific proportions (metal fluorosulfonate: 10-40 wt%, metal fluoride: 5-30 wt%) to achieve both good welding workability and electrode burning resistance simultaneously
2Strength
If Cr is incorporated into the core wire to achieve high Cr ferrite heat-resistant steel properties, then heat-resistant steel properties are improved, but the coating decomposes along with Joule heat generation causing electrode burning
Solution Approach 1:
The patent introduces metal fluorosulfonate as an intermediary substance in the covering material that acts as a protective barrier between the Cr-containing core wire and the welding environment, preventing the decomposition and electrode burning caused by Joule heat while allowing the Cr to provide its heat-resistant properties
3Shape
If the covering material density and coating diameter ratio are not optimized, then coatability is poor with surface unevenness, but optimizing these parameters is required to prevent electrode burning and improve weld quality
Solution Approach 1:
The patent optimizes the physical parameters including covering material density (1.8-2.2 g/cm³) and coating diameter to core wire diameter ratio (1.05-1.15) to achieve both good coatability with smooth surface and improved electrode burning resistance
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 optimized electrode design significantly enhances electrode burning resistance, coatability, and defect resistance, resulting in improved welding workability and a better bead appearance with reduced spatter generation.
Implementation Method 1
the coating decomposes along with Joule heat generation in the core wire during welding
Data Source
AI summary
[Problems] To provide a low-hydrogen coated electrode excellent in the electrode burning resistance and the coatability and capable of giving a weld metal with an excellent defect resistance. [Means for Solving the Problems] A low-hydrogen coated electrode includes a core wire and a covering material, in which either one or both of the core wire and the covering material contain, as alloy components, C, Si, Mn, Cr, Mo, and Fe, each in a predetermined amount, per total mass of the low-hydrogen coated electrode, the covering material contains, as flux components, Ca carbonate, a metal fluoride and SiO2, each in a predetermined amount, per total mass of the low-hydrogen coated electrode, the covering material contains substantially no carbonate except for the Ca carbonate, and the low-hydrogen coated electrode satisfies either one or both of a requirement that when a diameter of the low-hydrogen coated electrode is defined as a coating diameter and a diameter of the core wire is defined as a core wire diameter, a ratio of coating diameter to core wire diameter is from 1.50 to 1.80 and a requirement that the covering material has a density of from 0.200 to 0.260 g/cm3.