The United States is the largest producer and consumer of oil and gas in the world – and pipelines are the primary mode of transport. The American Petroleum Institute reports there are more than 320,000 miles of natural gas pipelines and approximately 185,000 miles of oil pipelines in the United States.
An astounding - but perhaps not surprising - fact given the age of our country's infrastructure, is that about 45% of the nation's pipelines are more than 50 years old. Simdex reports that more than 26,000 miles of new and replacement pipeline projects have been identified in the U.S. This forecast points to high demand for line pipe over the next several years.
But first, what is line pipe? Line pipe are large-diameter steel tubes that are welded end-to-end to create a pipeline to transport oil and gas. ArcelorMittal operations in the United States and throughout the world are well positioned to provide steel for line pipe. Both hot-rolled coils and discrete plates rolled from domestically produced slabs are used to make line pipe. The steel is then formed into a tube by our customers, where the seam is welded to form a pipe. These pipes can be up to 60-inches in diameter and 80-feet in length. Pipe sections are then welded together in the field by a fabricator to make the pipeline.
As fascinating as the production process is, it's equally important to understand that work is underway to further enhance the mechanical properties – or strength and toughness – of the steel used in oil and gas pipelines.
Line pipe steel must be strong enough to handle high internal pressures, especially for gas transmission. For a given pipe diameter, larger volumes of gas can be transported if the pipe can withstand elevated pressures, hence the requirement to use higher strength steel. But the steel must also be resistant to fracture. This poses a challenge to steel designers. In conventional steels, as strength increases, fracture resistance decreases. Line pipe steel must be internally clean, with minimal inclusions to avoid rupture initiation and must pass rigorous ultrasonic inspection. Line pipe steel must be tough enough to resist impacts and fracture along the pipeline. In gas lines, fractures can run for miles if the steel is not tough enough.
Today's line pipe is significantly stronger than the line pipe it will replace. ArcelorMittal produces the thickest, toughest line pipe steel in North America.
At ArcelorMittal, a strong emphasis, coupled with a significant investment in research, has been placed on continually improving the toughness and fracture resistance of steels used in pipelines. Today's line pipe is significantly stronger than the line pipe it will replace. ArcelorMittal produces the thickest, toughest line pipe steel in North America. The product development work in our Global R&D Centers in East Chicago, Indiana and Ghent, Belgium focuses on both hot-rolled coils used to produce spiral and electric resistance welded (ERW) pipes as well as plate steels used to make longitudinal submerged arc-welded (LSAW) pipes.
One significant R&D effort is thermomechanical control processing (TMCP) which allows for low carbon, micro-alloyed steels and enhances both strength and toughness. The low carbon chemistry achieved through TMCP also significantly improves weldability for the pipe maker and field fabricator. These efforts not only reduce the risk of failure in line pipe, but will also mitigate consequences in the event of a failure.
ArcelorMittal is developing economical, high quality pipeline steel in anticipation of pipeline projects worldwide including the Alaska LNG project, a project that will cover more than 800 miles of pipeline and require more than 700,000 tons of steel. What's notable about this project is that the terrain through which the pipeline passes may experience significant ground movement due to permafrost heaves and seismic shifts. The ground can move as much as an entire room – from floor to ceiling. ArcelorMittal is working on a strain-based design that will ensure the steel can accommodate the strains associated with that kind of shift in topography. We are also working to ensure that the pipeline can survive the extreme temperatures prevalent in oil rich areas such as Alaska or the Arctic. When temperature gets very low, steels becomes brittle. Our steels will exceed the necessary fracture resistance at the lowest temperatures these regions may see.
While pipelines are the primary way to transport oil and gas, there has been quite a bit of attention given to the delays in building new pipelines and repairing existing ones. In the absence of a pipeline, oil still needs to be delivered to customers so there has been increased reliance on the transport of oil via railroad tank cars.
Steel for tank cars is another area of developmental interest for ArcelorMittal. Our Burns Harbor plate mill has been the major supplier of steel plate for tank cars for decades. Our Global R&D Centers are developing new steels with higher toughness for rail cars transporting hazardous fluids, with improved puncture resistance. In the event of a derailment or impact, it is important to make sure steel tank cars aren't easily punctured. A tank car designed with higher strength steel will deform instead of puncture, delaying the release of contents and allowing more time for first responders to arrive.
ArcelorMittal is at the forefront of producing the most advanced steel products and solutions for all major markets – including energy transportation. We will continue to invest in our operations, our research and our products to ensure we deliver the safest and most cost-effective solutions for our customers and consumers.
Murali Manohar, Ph.D., P.E., head of plates, energy and infrastructure products at ArcelorMittal Global R&D - East Chicago, leads a team of engineering and technical professionals responsible for equipment, research activities and technical support to customers and corporate business units in the areas of plates, hot-rolled coils for energy, and industry and tubular products.
Dr. Manohar earned his Ph.D. and M.S. degrees in materials and welding engineering from The Ohio State University and M.S. and B.Tech degrees in metallurgical engineering from The Indian Institute of Technology, Madras, India. He is a Registered Professional Engineer in the Commonwealth of Pennsylvania. He has over 30 years of experience in the steel industry and almost 10 years with Welding Research Institute (BHEL) Trichy, India, before migrating to USA.
Dr. Manohar has authored several papers and publications on welding/weldability, laser surface modification, thermal cutting (laser and plasma) and physical metallurgy of steels. He has organized or co-organized several international conferences/symposia and represents the company in several industry committees. He is a member of several professional societies, honor societies and a peer reviewer for Welding Journal and Met Trans.
