Friction Stir Welding Thin Section for Heat Deformation Control

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Solution Overview

Problem

Friction stir welding causes deformation in metal members due to friction heat and pressing load from the FSW tool, leading to heat and load-induced deformation in the welding members.

Innovation Solution

A friction stir welding structure is developed with a thin section along the weld section on at least one of the members, where the thin section's thickness and tensile strength are optimized to minimize heat conduction and deformation, with specific relations defining the weld depth and thickness to ensure the weld section's strength is greater than the thin section's, allowing the load and friction heat to be distributed preferentially through the thinner section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If friction stir welding is performed to join metal members, then the members are strongly integrated, but heat deformation occurs in the welding members due to friction heat

Engineering Contradiction:

Improvewelding strengthVSAvoidheat deformation

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The welding member is divided into a main section and a thin section. The thin section has lower heat capacity and thermal conductivity, causing it to preferentially absorb friction heat during welding. This segmentation protects the main section from heat deformation while still achieving strong welding integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A thin section with specific local properties (reduced thickness and/or reduced thermal conductivity) is created at a predetermined position. This local modification causes the thin section to preferentially absorb friction heat and pressing load, protecting the main section from deformation while maintaining overall welding strength.

Inventive Principle:

Principle #3Local quality

2Strength

If friction stir welding is performed to join metal members, then the members are strongly integrated, but load-induced deformation occurs in the welding members due to pressing load

Engineering Contradiction:

Improvewelding strengthVSAvoidload deformation

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The welding member is segmented into main and thin sections. The thin section has reduced load-bearing capacity, causing it to preferentially absorb pressing load during welding. This protects the main section from load-induced deformation while the welding process still achieves strong integration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A thin section with modified local properties is created to preferentially absorb pressing load. The thin section's reduced thickness and/or strength characteristics cause it to deform preferentially under load, protecting the main section from deformation while maintaining overall welding integrity.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If a thin section is formed to reduce heat conduction, then heat deformation is prevented, but the member's overall strength may be reduced

Engineering Contradiction:

Improveheat deformation preventionVSAvoidmember strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The thin section's properties are specifically designed so that it preferentially absorbs friction heat and pressing load during welding. This controlled preferential deformation protects the main section while the thin section itself is positioned and dimensioned to maintain overall structural integrity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The thin section's thickness and/or thermal conductivity are modified to create preferential heat absorption. By carefully controlling these parameters, the thin section protects the main section from heat deformation while maintaining sufficient overall strength through proper positioning and dimensional relationships.

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

The thin section effectively reduces heat conduction to the main material, preventing heat deformation and minimizing deformation from the welding load, thereby maintaining the integrity of the welding members.

Implementation Method 1

The thin section effectively reduces heat conduction to the main material, preventing heat deformation

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

Friction stir welding is a method utilizing friction heat to join members together by heating and softening

Methodology Applied

Scientific EffectFriction heat: Friction

Implementation Method 3

heating and softening and also inducing a plasticizing flow by the rotation of a rotation tool

Methodology Applied

Scientific EffectPlasticizing flow: Plasticity

Data Source

PatentUS9278503B2Friction stir welding structure and power semiconductor device

Publication Date: 2016.03.08 ASTEMO LTD

AI summary

A friction stir welding structure is comprised of a first and a second member integrated into one piece by friction stir welding, and in which a thin section is formed along the friction stir weld section on at least one of either of the first and the second member.