Flux-Cored Wire Composition for High-Current Positional Welding

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Solution Overview

Problem

Existing flux-cored wires face challenges in achieving good bead appearance and preventing burn-through of molten metal, especially in overhead and vertical welding positions, due to limitations in welding current range and arc voltage.

Innovation Solution

A flux-cored wire with a specific configuration, including strong deoxidizing metal elements like Mg and Al, and fluoride powders, is developed to inhibit welding defects and ensure high efficiency at higher welding currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If welding current is increased to improve welding efficiency, then productivity increases, but burn-through of molten metal and deterioration of bead appearance occur in vertical and overhead welding

Engineering Contradiction:
Improvewelding efficiencyVSAvoidwelding quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the flux by specifying precise ranges for strong deoxidizing metal elements (15-35 mass%), fluoride powder (10-45 mass%), and their particle size distributions. These parameter changes enable the flux to control molten metal behavior at higher welding currents, allowing welding efficiency improvement without quality deterioration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite flux composition combining multiple types of strong deoxidizing metal elements (Mg, Al, and others) with fluoride powders in specific ratios. This composite material approach creates synergistic effects that enhance both weld pool stability and bead appearance quality, enabling high-current welding in vertical and overhead positions without burn-through.

Inventive Principle:
Principle #40Composite materials

2Productivity

If welding current is increased beyond 200 A, then high efficiency welding is achieved, but welding defects such as burn-through occur in overhead and vertical positions

Engineering Contradiction:
Improvewelding speedVSAvoidwelding defects
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful effect of high welding current (which causes burn-through) into a beneficial effect by using the flux composition to enhance arc stability and molten metal control. The strong deoxidizing metal elements and fluoride powders work together to stabilize the arc and control fluidity, allowing the high current to be used beneficially for faster welding without producing defects.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If flux composition is optimized for low to medium current range, then spatter is reduced and weldability is improved, but welding efficiency is limited

Engineering Contradiction:
ImproveweldabilityVSAvoidwelding efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention creates a dynamic flux composition that adapts to different welding conditions. The specific particle size ranges and compositional ratios allow the flux to provide optimal performance across a wide current range (including high currents >200 A), rather than being fixed for low-to-medium currents only. This dynamic adaptability enables both good weldability and high welding efficiency.

Inventive Principle:
Principle #15Dynamics

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 flux-cored wire enables efficient welding in all positions, including overhead and vertical, with high welding currents exceeding 200 A, while maintaining a good bead appearance and preventing burn-through.

Implementation Method 1

the flux includes strong deoxidizing metal elements (flux) and at least one fluoride powder (flux), and the strong deoxidizing metal elements (flux) include Mg and Al

Methodology Applied
Scientific EffectDeoxidation: Reduction

Implementation Method 2

a total content of the at least one fluoride powder (flux) is 10 to 45 mass % relative to the total mass of the flux

Methodology Applied
Scientific EffectSlag formation:

Implementation Method 3

gas shielded arc welding method that uses the flux-cored wire

Methodology Applied
Scientific EffectArc heating: Electric Arc

Data Source

PatentUS12296411B2Flux-cored wire and welding method
Publication Date: 2025.05.13 KOBE STEEL LTD

AI summary

A flux-cored wire comprising a flux which is a core and a hoop which is an outer skin or sheath is described. The flux includes a strong deoxidizing metal element containing Mg and Al, and a fluoride powder. At least 60 mass % of a strong deoxidizing metal powder related to the strong deoxidizing metal element has a grain size of at most 150 μm. At least 60 mass % of the fluoride powder has a grain size of at most 75 μm. The flux is present at a concentration of 10-30 mass % relative to a total mass of the flux-cored wire. The flux-cored wire also requires a specific composition of elements.