Flux-Cored Wire Moisture Adsorption Control

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Solution Overview

Problem

Conventional flux-cored wires with slag-making agents like TiO2 have high moisture absorbency, leading to susceptibility to lower temperature cracking, which existing solutions, such as specifying the specific surface area of titanium oxide, do not adequately address to meet current and future weldability requirements.

Innovation Solution

A flux-cored wire with a flux containing 20 to 50 mass% titanium and titanium oxide, a moisture adsorption area of 0.020 to 0.100 m^2/g, a tensile strength of 300 to 500 N/mm^2, a filling ratio of 10 to 20 mass% flux, and a hull thickness of 0.10 to 0.30 mm, which reduces moisture absorption and ensures weldability while preventing arc concentration and spatter generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a slag-making agent such as TiO2 is contained in flux to enable all-position welding, then weldability is improved, but moisture absorbency increases leading to lower temperature cracking

Engineering Contradiction:
ImproveweldabilityVSAvoidmoisture absorbency
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical and chemical parameters of the flux components, specifically controlling the particle size distribution (D50: 3.0-7.0 μm, D90: 15.0-25.0 μm) and chemical composition (TiO2: 20-50 mass%, Al2O3: 1.0-2.5 mass%, Mn: 15-25 mass%, Ni: 15-25 mass%). These parameter changes reduce the specific surface area and moisture adsorption capacity while maintaining the slag-making functionality for all-position welding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite flux system combining multiple materials (TiO2, Al2O3, Mn, Ni, and other components) in specific proportions. This composite approach allows the flux to maintain effective slag-making properties for all-position welding while the overall composition has reduced moisture absorbency compared to TiO2-heavy formulations.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If the specific surface area of titanium oxide is reduced to suppress lower temperature cracking, then moisture absorption resistance improves, but weldability may deteriorate

Engineering Contradiction:
Improvelower temperature crackingVSAvoidweldability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent optimizes the particle size parameters of TiO2 and other flux components, setting D50 between 3.0-7.0 μm and D90 between 15.0-25.0 μm. This controlled particle size distribution reduces the specific surface area and moisture adsorption while maintaining adequate reactivity for weldability through the balanced chemical composition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different particle size characteristics to different components in the flux mixture. By controlling the particle size distribution of each component (TiO2, Al2O3, Mn, Ni) within specific ranges, the flux achieves local optimization where coarser particles reduce moisture absorption while finer particles maintain chemical reactivity for welding.

Inventive Principle:
Principle #3Local quality

3Productivity

If flux content is increased to improve weld metal performance, then deposition efficiency improves, but moisture adsorption area increases

Engineering Contradiction:
Improvedeposition efficiencyVSAvoidmoisture adsorption area
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical parameters of the flux particles, specifically controlling particle size (D50: 3.0-7.0 μm, D90: 15.0-25.0 μm) and shape characteristics. These changes reduce the specific surface area per unit mass, allowing higher flux content for improved deposition efficiency while limiting the total moisture adsorption area through optimized particle morphology.

Inventive Principle:
Principle #35Parameter changes

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

Significantly improves resistance to moisture absorption, suppresses lower temperature cracking, and maintains weldability at desired levels, ensuring reliable wire feedability and reducing spatter and arc concentration.

Implementation Method 1

the slag-making agent such as TiO 2 has a property of absorbing moisture. Accordingly, flux-cored wires containing the slag-making agent have high moisture absorbency

Methodology Applied
Scientific EffectMoisture absorption: Absorption (physical)

Implementation Method 2

a flux-cored wire for arc welding

Methodology Applied
Scientific EffectArc heating: Electric Arc

Data Source

PatentEP2905105B1Flux-cored wire
Publication Date: 2019.02.06 KOBE STEEL LTD
  • EP2905105B1 patent drawingFigure 1(a)~1(b)
  • EP2905105B1 patent drawingFigure 2(a)~2(e)
  • EP2905105B1 patent drawingFigure 3

AI summary

The present invention addresses the problem of providing a flux-cored wire that secures weldability at the level that has been demanded in the past while being able to further limit the occurrence of lower temperature cracking by improving resistance to moisture absorption compared to conventional wire. The problem is solved by a flux-cored wire (10) for arc welding in which flux (2) is filled inside a steel hull (1), the flux-cored wire (10) being characterized in that the flux (2) contains 20-50 mass% titanium and titanium oxide calculated as TiO2 and the moisture adsorption area of the flux-cored wire is 0.020-0.100 m2/g.