Investigation of microstructure, corrosion, and mechanical properties of MIG welded API X70 and SS401 joints

Editorial Board PCSS Journal; Lochan Sharma; Amman Jakhar; Kanika Sharma; Mukhtiar Singh; Mandeep Singh Rayat; Mariia Liaskovska; Rashad Abaszade

doi:10.15330/pcss.27.2.242-252

Authors

Lochan Sharma Faculty of University Center of Research & Development, Chandigarh University, Mohali-140413, Punjab, India
Amman Jakhar Faculty of Mechanical Engineering Department, Chandigarh University, Mohali-140413, Punjab, India
Kanika Sharma Faculty of Computer Science and Engineering Department, Chandigarh University, Mohali-140413, Punjab, India
Mukhtiar Singh Lovely Professional University Jalandhar - Delhi, Grand Trunk Rd, Phagwara, Punjab, India
Mandeep Singh Rayat Lovely Professional University Jalandhar - Delhi, Grand Trunk Rd, Phagwara, Punjab, India
Mariia Liaskovska Department of Biological and Medical Chemistry named after Academician G.O. Babenko, Ivano-Frankivsk National Medical University, Ivano-Frankivsk, Ukraine
Rashad Abaszade Department of Electronics and Automatics, Azerbaijan State Oil and Industry University, Baku, Azerbaijan; Department of Ecology, Azerbaijan University of Architecture and Construction, Baku, Azerbaijan; Department of Materials Science and New Materials Technologies, Tashkent State Technical University named after Islam Karimov, Tashkent, Uzbekistan; Electrical and Electronics Engineering Department, Turan International Research Institute, Baku, Azerbaijan

DOI:

https://doi.org/10.15330/pcss.27.2.242-252

Keywords:

Metal Welding, X70, SS401, HAZ, Fusion Zone, Corrosion Resistance, Microstructure, Fractography

Abstract

In present study, Metal Inert Gas (MIG) welding with ER309L austenitic filler wire was used to weld API X70 and SS 401 steel. This particular joint is mainly used in oil and gas plants where stainless steel need to be connected to the high strength low alloy carbon steel pipelines. MIG welding process is cost effective in these industrial fabrication and maintenance applications as it has high deposition rates and productivity. The investigation focuses on the influence of two distinct heat input levels-HI-1 (0.814 kJ/mm) and HI-2 (0.573 kJ/mm) on the weldment’s microstructure, mechanical performance, and corrosion resistance in simulated seawater and sodium thiosulphate environments. Microstructural examination revealed that the lower heat input (HI-2) produced coarser grains and reduced martensite-austenite (MA) constituent formation in the fusion zone, resulting in improved toughness. Conversely, the higher heat input (HI-1) led to finer grains but increased brittleness. In the heat-affected zone (HAZ), API X70 exhibited grain coarsening-induced softening, while SS 401 demonstrated sensitization and MA phase development, negatively affecting corrosion resistance. Corrosion assessments indicated superior performance of SS 401 over API X70, with minimal weight loss (0.75 mm/year) in seawater due to its protective chromium-rich passive film. However, the dissimilar welded joints, particularly those produced with HI-1-showed significant corrosion degradation (2.1 mm/year in thiosulphate solution), primarily due to microstructural inhomogeneity and galvanic coupling. Mechanical testing results showed that HI-2 welds offered enhanced impact toughness (196 J in the fusion zone) compared to HI-1 (154 J), although the API X70 HAZ under HI-2 exhibited decreased toughness (120 J) likely due to thermal softening. Hardness measurements revealed maximum values near the fusion boundary (~380 HV in HI-1 samples), with noticeable softening in the HAZ regions. These findings suggest that optimizing heat input is critical for balancing mechanical integrity and corrosion resistance in dissimilar metal joints.

References

S. Liu, Y. Zhang, H. Li, X. Wang Weldability of API 5L X70 steel under submerged arc welding conditions, Journal of Manufacturing Processes, 28, 560 (2017); https://doi.org/10.1016/j.jmapro.2017.07.016.

W. D. Callister, Materials science and engineering: An introduction, 7th ed., Wiley, New York (2007).

H. Yang, L. Zhang, Y. Li, Q. Chen Corrosion inhibition in API 5L X70 steel using rare earth compounds, Corrosion Science, 182, 109278 (2021); https://doi.org/10.1016/j.corsci.2020.109278.

A. Singh, R. K. Singh, S. Das Hydrogen embrittlement susceptibility in API 5L X70 steel: Effects of microstructure and cold rolling, Journal of Materials Research and Technology, 9(5), 10456 (2020); https://doi.org/10.1016/j.jmrt.2020.07.053.

J. W. Park, S. H. Lee, Y. M. Kim, Microstructure evolution during thermomechanical controlled processing of API 5L X70 steel, Materials Science Forum, 980, 55 (2019); https://doi.org/10.4028/www.scientific.net/MSF.980.55.

S. Kou Welding metallurgy, 2nd ed., Wiley-Interscience, Hoboken, NJ (2003).

American Welding Society Dissimilar metal welding guidelines, AWS, Miami, FL (n.d.).

J. C. Lippold, D. J. Kotecki, Welding metallurgy and weldability of stainless steels, Wiley-Interscience, Hoboken, NJ (2005).

ASM International ASM Handbook, Volume 6: Welding, Brazing, and Soldering, ASM International, Materials Park, OH (1993).

R. S. Mishra, M. W. Mahoney, Friction stir welding and processing, ASM International, Materials Park, OH (2007).

STM International ASTM E8/E8M-21: Standard test methods for tension testing of metallic materials, ASTM International, West Conshohocken, PA (2021); https://doi.org/10.1520/E0008_E0008M-21

D. H. Kim, S. J. Kim, C. Y. Kang, Effect of heat input on microstructure and mechanical properties of API 5L X70 pipeline steel welds, Welding Journal, 94(2), 45s (2015).

Y. Wang, X. Liu, J. Zhang, Impact of cooling rates on microstructure and mechanical properties in API X70 welds, Metallurgical and Materials Transactions A, 46(2), 600 (2015); https://doi.org/10.1007/s11661-014-2665-4

J. F. Santos, T. Watanabe, H. Okado, Optimization of dissimilar welding parameters for API X70 and SS400 using gas metal arc welding, Journal of Manufacturing Science and Engineering, 135(4), 041009 (2013); https://doi.org/10.1115/1.4024701.

M. Sharma, V. K. Singh, R. Kumar, Strategies for minimizing cold cracking in API X70 to SS400 weld joints, Welding International, 32(6), 456 (2018); https://doi.org/10.1080/09507116.2017.1343634.

V. Ramasamy, S. K. Albert, A. K. Bhaduri, Effect of filler material on mechanical properties of dissimilar welded joints between API X70 and SS400 steels, Materials & Design, 55, 483 (2014); https://doi.org/10.1016/j.matdes.2013.10.018.

T. Kamal, M. A. Raza, S. A. Hussain,Mechanical, microstructure, and corrosion characterization of dissimilar austenitic 316L and duplex 2205 stainless-steel ATIG welded joints, Materials, 15(7), 2470 (2022); https://doi.org/10.3390/ma15072470.

N. Ghosh, S. K. Albert, A. K. Bhaduri, GMAW dissimilar welding of AISI 409 ferritic stainless steel to AISI 316L austenitic stainless steel by using AISI 308 filler wire, Engineering Science and Technology, an International Journal, 20, 1334 (2017); https://doi.org/10.1016/j.jestch.2017.05.009.

M. Rahmani, M. K. Besharati-Givi, Evaluation of microstructure and mechanical properties in dissimilar austenitic/super duplex stainless steel joint, Journal of Materials Engineering and Performance, 23, 3745 (2014); https://doi.org/10.1007/s11665-014-1153-3.

J. Labanowski, Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints, Journal of Achievements in Materials and Manufacturing Engineering, 20, 255 (2007).

L. Peguet, B. Malki, B. Baroux Influence of cold working on the pitting corrosion resistance of stainless steels, Corrosion Science, 49, 1933–1948 (2007); https://doi.org/10.1016/j.corsci.2006.11.010.

S. Jana, Effect of heat input on the HAZ properties of two duplex stainless steels, Journal of Materials Processing Technology, 33, 247 (1992); https://doi.org/10.1016/0924-0136(92)90234-6.

J. Verma, V. Taiwade, A comparative study on the effect of electrode on microstructure and mechanical properties of dissimilar welds of 2205 austeno-ferritic and 316L austenitic stainless steel, Materials Transactions, 57, 494 (2016); https://doi.org/10.2320/matertrans.M2015403.