Critical review of automotive steels spot welding: process, structure and properties

Abstract

Spot welding, particularly resistance spot welding (RSW), is a critical joining process in automotive industry. The development of advanced high strength steels for applications in automotive industry is accompanied with a challenge to better understand the physical and mechanical metallurgy of these materials during RSW. The present paper critically reviews the fundamental understanding of structure–properties relationship in automotive steels resistance spot welds. The focus is on the metallurgical characteristics, hardness–microstructure correlation, interfacial to pullout failure mode transition and mechanical performance of steel resistance spot welds under quasi-static, fatigue and impact loading conditions. A brief review of friction stir spot welding, as an alternative to RSW, is also included.

Keywords:

• Resistance spot welding
• Automotive steels
• AHSS
• Failure mode
• Microstructure
• Mechanical performance

The authors would like to thank Professor Harry Bhadeshia for providing the opportunity to prepare a critical review on the published data on the metallurgical and mechanical characteristics of automotive steels spot welds. We would also like to thank all the undergraduate and postgraduate students who have patiently and carefully conducted a number of projects at Amirkabir Unviersity of Technology, over the years including Hamidreza Asgari, Dr Seyed Mostafa Mouavizadeh Noughabi, Amir Afrouz Daghoughi, Tara Mansouri, Sasan Amirabdollahian, Pooria Movahed, Sina Kolahgar, Mohammad Sanaee, Dorsasadat Safanama, Farzaneh Alimohammadi, Masoud Alizadeh Shamsabadi, Faryal Hakami, Nina Asadi Moghadas, Samaneh Bayrampour, Maryam Masoumi, Farnoush Falsafi, Ayda Shahryari, Nooshin Mortazavi, Maryam Bazyaran, Mina Salehi, Ali Tavasolizadeh and Sara Abouzari. Special thanks also go to Novinsazan Setareh Sanat for providing the RSW equipment and Iran University of Science and Technology and Dr Masoud Goodarzi for accommodating the resistance spot welding equipment and their kind cooperation for using it.