고강도강 다층 용접금속 재가열부의 미세조직 및 기계적 특성

다국어 초록 (Multilingual Abstract)

A large fraction of reheated weld metal is formed during multi-pass welding, which significantly affects the reliability and stability of the welded structures. In this study, the effect of reheating on the mechanical properties and microstructure of high-strength steel welds during multi-pass welding was investigated. Two kinds of high-strength steel welds with different hardenabilities, i.e., welds L (low hardenability) and H (high hardenability), were produced by single-pass, bead-in-groove welding, and both welds were thermally cycled to various peak temperatures to simulate the reheated welds using a Gleeble simulator. In as-welded weld L, acicular ferrite developed extensively in the grain interior, while grain boundary ferrite and Widmanstätten ferrite formed along the prior austenite grain boundaries. The microstructure of as-welded weld H consisted mainly of bainite, with some acicular ferrite and coalesced bainite. The microstructural changes due to thermal cycling were observed by scanning electron microscopy and correlated with the mechanical properties.

목차 (Table of Contents)

• Abstract
• 1. 서론
• 2. 실험 방법
• 3. 실험 결과 및 고찰
• 4. 결론
• References

참고문헌 (Reference)

1 이윤기, "극 저탄소강의 Intercritical coarse grained HAZ에서의 M-A상과 인장특성 간의 상관관계" 대한용접접합학회 28 (28): 99-103, 2010

2 강용준, "고강도 저합금강 용접금속의 미세조직과 기계적 특성에 미치는 니켈 함량의 영향" 대한용접접합학회 30 (30): 49-54, 2012

3 Yongjoon Kang, "Variation in the Chemical Driving Force for Intragranular Nucleation in the Multi-pass Weld Metal of Ti-Containing High-Strength Low-Alloy Steel" Springer Nature 46 (46): 3581-3591, 2015

4 Nobuo Tezuka, "Toughness Degradation Mechanism for Reheated Mo-Ti-B Bearing Weld Metal." Iron and Steel Institute of Japan 35 (35): 1232-1238, 1995

5 문준오, "Ti-Nb첨가 저합금강 용접열영향부에서의 열-응력 이력이 미세조직 및 기계적 성질에 미치는 영향에 관한 연구" 대한용접접합학회 31 (31): 44-49, 2013

6 E. Keehan, "Three-dimensional analysis of coalesced bainite using focused ion beam tomography" Elsevier BV 59 (59): 877-882, 2008

7 G.M. Evans, "The Effect of Heat Input on the Microstructure and Properties of C-Mn All-Weld-Metal Deposits" 61 : 125s-132s, 1982

8 J.H. Chen, "Study on Impact Toughness of C-Mn Multilayer Weld Metal at -60℃" 72 : 19s-27s, 1993

9 Shigeru Ohkita, "Recent Development in Controlling the Microstructure and Properties of Low Alloy Steel Weld Metals." Iron and Steel Institute of Japan 35 (35): 1170-1182, 1995

10 D.S. Sarma, "On the Role of Non-metallic Inclusions in the Nucleation of Acicular Ferrite in Steels" 49 (49): 1063-1074, 2009

11 K. Brunelli, "Microstructural Evolution of a Continuously Cooled Air Hardening Steel" Springer Nature 2 (2): 56-66, 2013

12 홍현욱, "M-A 제어를 통한 HAZ 인성 향상 기술" 대한용접접합학회 28 (28): 4-8, 2010

13 K. Easterling, "Introduction to the physical metallurgy of welding" 20-, 1983

14 Yongjoon Kang, "Influence of Ti on Non-Metallic Inclusion Formation and Acicular Ferrite Nucleation in High-Strength Low-Alloy Steel Weld Metals" 대한금속·재료학회 20 (20): 119-127, 2014

15 Z.L. Zhou, "Influence of Local Brittle Zone on the Fracture Toughness of High-Strength Low-Alloyed Multipass Weld Metals" 11 (11): 87-92, 1998

16 E. Surian, "Influence of Chromium on the Mechanical Properties and Microstructure of Weld Metal from a High-Strength SMA Electrode" 73 : 45s-53s, 1994

17 Yongjoon Kang, "Factors Affecting the Inclusion Potency for Acicular Ferrite Nucleation in High-Strength Steel Welds" Springer Nature 47 (47): 2842-2854, 2016

18 W.W. Bose-Filho, "Effects of alloying elements on the microstructure and inclusion formation in HSLA multipass welds" Elsevier BV 58 (58): 29-39, 2007

19 K.S. Kweon, "Effects of M-A Constituents on Toughness in the ICCG HAZ of SA508-cl.3 Pressure Vessel Steel" 17 (17): 203-213, 1999

20 M. H. Avazkonandeh-Gharavol, "Effect of chromium content on the microstructure and mechanical properties of multipass MMA, low alloy steel weld metal" Springer Nature 44 (44): 186-197, 2009

21 G. Kim, "Considerations in Welding for the Cr-Mo Type Steel Pressure Vessels" 18 (18): 30-37, 2000