Structure-Property Correlations in Microalloyed Steels for Structural and Line-Pipe Applications

• Published in: Key engineering materials 1993-01, Vol.84-85, p.250-270
• Main Authors: Ramaswamy, V., Mishra, Sanak, Chaudhuri, S.K.
• Format: Article
• Language: English
• ISSN: 1013-9826; 1662-9795; 1662-9795
• DOI: 10.4028/www.scientific.net/KEM.84-85.250

Thermomechanical controlled processing (TMCP) of microalloyed steels has seen remarkable growth in the last two decades, not merely in terms of tonnage but also in the diversity of applications, novel alloy design concepts, and processing techniques. Steel Authority of India Limited (SAIL) entered the high strength steel scene in 1975 with the successful development and production of niobium/vanadium bearing microalloyed high tensile plates, joists and angles for structural applications. Success of this development led to a major challenge in the second phase of the programme which was comprised of development of various categories of line pipe steels. First, API-X-60 grade spirally welded pipes for non-sour gas application were developed for the oil and natural gas sector. This was followed by development of API X-52/X-56/X60 grades of plates for the manufacture of U-O-E pipes. In recent times, efforts have been made to develop API x-60 grade plates in thicker gauges, specially suitable for making pipes for transportation of sour gas. Besides these basic grades, a high strength variety of line pipe steel (API) X-70) has also been developed with acicular ferrite microstructure.