Toughness Recovery of Welded Pipe API 5L Grade B through Quenching and Tempering Treatment

Abstract:

API 5L Grade B steel pipe used for the oil and gas industries must meet toughness requirement of higher than 27 Joule and hardness value of lower than 248 HV. The welding process during piping installation sometimes generates lower toughness. Thus additional heat treatment was necessary to recover their superior toughness. Quenching from 900 °C into water or oil medium followed by tempering at 550 °C, 600 °C and 650 °C for 1 hour was selected in this study. Charpy impact test was used to access their toughness data, while the hardness was measured using micro Vickers hardness. It was found that the highest toughness of 168 Joule with a hardness of 166 HV_1.0 was generated in the welding zone after water quenching followed by tempering at 600 °C treatment. The metallographic investigation reveals fully martensite tempered microstructures. These acquired toughness and hardness values were in accordance with API 5L pipe standard requirements.

• Periodical: Key Engineering Materials (Volume 939)
• Pages: 19-24
• DOI: https://doi.org/10.4028/p-u6mw1b
• Online since: January 2023
• Authors: Viki Sofyan Hadi, Fahmi Mubarok*, Muhammad Fitrullah
• Keywords: API 5L Steel Pipe, Impact Charpy, Quenching-Tempering, Toughness, Welding

References

[1] S.H. Hashemi, D. Mohammadyani.: Characterization of weldment hardness, impact energy and microstructure in API X65 steel. International Journal of Pressure Vessels and Piping, 8–15 (2012).

DOI: 10.1016/j.ijpvp.2012.05.011

[2] L.B. Godefroid, B.M. Sena, V.B. da Trindade Filho.: Evaluation of Microstructure and Mechanical Properties of Seamless Steel Pipes API 5 Type Obtained by Different Processes of Heat Treatments, 514-522 (2017).

DOI: 10.1590/1980-5373-mr-2016-0545

[3] API Specification 5L Standard, 46th Edition, April 2018, American Petroleum Institute (API), Washington, DC, USA, (2018).

[4] S.D. Kim, B.A. Kang, K.H. Lee.: Mechanical Properties of Welded API 5L Gr B Steel for Hydrogen Piping, 192-200 (2019).

[5] S.H.A. Alfatlawi.: Influence the Quenching and Tempering on the Microstructure, Mechanical Properties and Surface Roughness, of Medium Carbon Steel, 125-135 (2011).

DOI: 10.32852/iqjfmme.vol18.iss1.78

[6] H. Zakerinia, A. Kermanpur, and A. Najafizadeh.: Color Metallography a Suitable Method or Characterization of Martensite and Bainite in Multiphase Steels, 14-18 (2009).

[7] J. Vatavuk, G.E. Totten, J.E. Nucci, L.L.M. Albano, and L.d.C.F. Canale.: Comparative Impact Behavior of High-C Steel After Conventional Quenching, Tempering, and Austempering, 220-231 (2016).

DOI: 10.1520/mpc20150042