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TIG-FSW Hybrid 용접기술을 이용한 이종재료 Al6061 Alloy - STS 용접부의 용접성에 관한 고찰

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Author(s)
전근홍
Issued Date
2009
Abstract
최근, 각종 산업분야에 있어서 경량화 구조가 증가하고 있으며 특히 수송기계분야(철도차량, 자동차, 선박, 항공기 등)에 있어서 경량화에 의한 연비 절감 및 지구 환경보호와 에너지 절감에 대한 요구가 높아짐에 따라 경량 부재의 적용이 빠른 속도로 확대되고 있다.
1981년 영국의 용접연구소(TWI)에서는 비 용융 접합공정인 Friction stir welding(FSW:마찰교반접합) 방법을 개발하였다. FSW기술은 마찰용접에서 유래되어 용접에 의한 변형이 적고 용접결함, 흄, 유해광선의 발생 없이 우수한 품질의 접합부를 얻을 수 있으며, 기계적 특성 또한 우수한 접합 방법이다. 경량금속(Al, Mg, Cu합금 등)은 기존 용융용접에서 문제시 되고 있는 응고균열, 기공, 산화 등의 결함을 최소화 할 수 있는 고상접합공정인 Friction stir welding이 다양한 산업분야에서 크게 주목받고 있으며 이미 적용되어지고 있다. 접합대상이 기존의 알루미늄과 알루미늄 동종계의 경량합금에서 이종재의 경량합금의 접합 영역 뿐 아니라 경합금과 철강 재료의 접합의 영역까지 확대 되고 있다. 모든 구조물을 지지하는 부분의 부재는 강도가 뛰어난 부재를 사용하여야 하므로 경량합금과 철계 합금의 이종접합이 필연 시 되고 있다. FSW를 이용하여 이종재료를 접합할 경우 물리적인 성질이 상이하여 기존 동종재료의 FSW접합 방식으로는 건전한 접합부를 쉽게 얻을 수 없어 두 재료 중 연질인 재료에 마찰교반접합 Tool을 삽입하여 건전한 접합부를 얻은 결과가 보고된바 있으나 아직은 연구가 많이 미흡한 실정이다.
따라서 본 연구는 비강도가 우수한 알루미늄 합금과 우수한 부식특성 높은 강도를 나타내는 스테인리스강의 이종재료를 FSW와 TIG welding을 결합한 하이브리드 용접을 수행함으로써 접합부의 미세조직 및 기계적 강도를 측정하고 접합특성을 파악하여 선박, 자동차 및 항공기, 수송기계 부품제작에 적용 가능성을 고찰하고자 한다.
Alternative Title
A Study on Weldability of TIG Assisted Friction Stir Dissimilar Welding of Al6061 Alloy and STS Sheet
Alternative Author(s)
Jeon, Geun Hong
Affiliation
조선대학교 선박해양공학과 대학원
Department
일반대학원 선박해양공학과
Advisor
방한서
Awarded Date
2010-02
Table Of Contents
CONTENTS

List of Table ···································································· Ⅲ
List of Figures ·································································· Ⅳ
Abstract ·········································································· Ⅴ

Chapter 1. Introduction
1 . 1 Background & Purpose ····································· 1

Chapter 2. Theoretical background
2 . 1 Principles and characteristics of FSW ··············· 2
2 . 2 Principles and characteristics of GTAW ············ 5
2 . 3 Type and characteristics of aluminum alloy ······· 7
2 . 4 Type and characteristics of stainless steel ······ 11

Chapter 3. Experiment method of TIG-FSW process
3 . 1 Experimental work for TIG-FSW ··················· 14
3.1.1 TIG-FSW equipment and experimental setup ···· 14
3.1.2 Details of objective materials ··························· 16
3 . 2 Description of tool material ···························· 18
3 . 3 TIG assisted Friction stir welding condition ····· 20
3 . 4 Experiment method ········································ 23
3.4.1 Tensile test ···················································· 23
3.4.2 Hardness test ················································· 24
3.4.3 Bending test ··················································· 25
3.4.4 Micro structure analyses ·································· 26

Chapter 4. Experimental Investigation & Results
4 . 1 Welding condition and bead shape ··················· 27
4.1.1 Experiment by TIG Welding ····························· 27
4.1.2 Experiment by Friction Stir Welding ················· 28
4.1.3 Experiment by TIG assisted Friction Stir Welding
······································································ 31
4 . 2 Tensile test results········································ 37
4.2.1 Tensile test of similar joint (Al6061-T6) ········ 37
4.2.2 Tensile test of FSW dissimilar joint ················ 38
4.2.3 Tensile test of TIG assisted FSW dissimilar joint
······································································ 41
4 . 3 Hardness test results ······································47
4 . 4 Bending test results ······································· 49
4 . 5 Micro structure analyses of dissimilar joint ····· 51
4.5.1 Micro structure of FSW dissimilar joint ············ 51
4.5.2 Micro structure of TIG assisted FSW dissimilar
joint ······························································ 51
4.5.3 Microstructure analyses by using SEM and EDS··54

Chapter 5. Conclusion ·········································· 58
Reference ··························································· 60
Degree
Master
Publisher
조선대학교
Citation
전근홍. (2009). TIG-FSW Hybrid 용접기술을 이용한 이종재료 Al6061 Alloy - STS 용접부의 용접성에 관한 고찰.
Type
Dissertation
URI
https://oak.chosun.ac.kr/handle/2020.oak/8423
http://chosun.dcollection.net/common/orgView/200000239200
Appears in Collections:
General Graduate School > 3. Theses(Master)
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