WE Colloquium: Vikas Patel, Coil Joining of 3rd Generation Advance High Strength Steel

Abstract

In the highly competitive automotive market along with the energy and environment concerns, the automotive manufactures are continuously looking for methods to reduce fuel consumption and CO2 emissions. This can be achieved via an effective weight reduction of vehicles by employing 3rd generation advance high strength steel (AHSS) which also improve the crash performance of the automotive body parts. Recently product development team of ArcelorMittal R&D has developed several grades of 3rd generation AHSS, which has more 2000 MPa ultimate tensile strength. Replacing the existing steel grades in automotive cars with new 3rd generation AHSS can save as much as 20 to 30 % of overall weigh of car. To produce theses grade in large scale continuous environment of steel industry, head end of the coil is to weld with tail end of other coil that being in production. This process is known as a coil joining in steel industry. Among coil joining processes, welding is a key process and its efficiency has a deep impact on productivity and throughput; speed is increased and line stops are reduced.  In continuous steel processing lines, three major welding technologies are being used: flash butt and laser welding for heavy gauge and resistance seam welding for lighter gauge. A strip break during production results in downtime of 48 to 72 hours.  Such breaks are most likely to occur at the weld because the weld has poor resistance to bending stress across it.  3rd generation AHSS products have very poor weldability. Immediately after welding, the weld zone and its surrounding area are converted into a fully martensitic structure, resulting in a very brittle weld. Application of a small bending stress across this brittle zone results in weld breaks and downtime. Standard best practice in dealing with AHSS steel is to heat treat the weld zone immediately after the welding is completed.  In spite of this, some of AHSS grades still experience brittle martensitic structure in the weld zone.  In this talk, methods to weld AHSS grade will be discussed along with the significance of coil joining in steel industry.

Bio

Dr. Patel is currently a Research Engineer in the Global Research and Development Department of ArcelorMittal. He received his Bachelor in Mechanical Engineering from Veer Narmad South Gujarat University, Surat, India, in 2007; Master of Science in Industrial Technology from Illinois Institute of Technology, Chicago, USA, in 2009; and Doctor of Philosophy in Mechanical Engineering with specialization in Material Science/Welding from Ryerson University, Toronto, Canada, in 2014. His research interest are in the field of welding and joining processes, welding metallurgy, materials characterization and additive manufacturing of metals. Dr. Patel’s Ph.D. thesis topic was “Ultrasonic Spot Welding of Lightweight Alloys.” During his Ph.D. study, Dr. Patel has published 16 refereed publications including 13 journal papers and 3 conference papers. His Ph.D. research work has been cited 244 times by other. Dr. Patel has received Distinction Award in bachelor program and Highest Standard of Academic Achievement Award in master program. Dr. Patel has been nominated for the prestigious Governor General Gold Medal Award by the Department of Mechanical and Industrial Engineering of Ryerson University. During his PhD study, he has received a number of scholarships and awards. After finishing his Doctorate study, Dr. Patel has continue worked with Ryerson University as a Post-Doctoral Fellow for four months. After joining, ArcelorMittal Global R&D in USA, Dr. Patel has established state of the art coil joining research lab. Recently, Dr. Patel and his team members have developed a method to weld high carbon highly alloy 3rd generation advance high strength steel. Therefore, he was awarded with Research Innovation Technical Award of 2015 from ArcelorMittal Global R&D in his very first year of employment. This innovation is currently under internal review for patenting procedure. Along with research, Dr. Patel is voluntary working as a reviewer for several international journals and has reviewed more than 50 journal papers. In 2015 year, Dr. Patel got ‘Outstanding Reviewer Award’ from Materials and Design Journal.