Chemistry and Processing Considerations for Production of API-X80 Plates at ArcelorMittal Burns Harbor Plate Mill

摘要

With increasing market demand for high strength linepipe plates, a product development program was initiated at ArcelorMittal USA, Burns Harbor Plate Mill for the production of plates to be converted into API 5LX80 pipes. Mill trials were preceded by laboratory work consisting of melting, rolling and testing of 50 kg heats, with the aim of evaluating and selecting the final candidates for actual plate production. The candidates selected were: a C-Mn-Nb and a C-Mn-Nb-Mo alloy design both processed with thermo-mechanical rolling technology without the use of accelerated cooling for 16 mm maximum thickness. Plates were converted into non-expanded pipes and mechanical properties were evaluated after pipe making. The plates exhibited excellent tensile and toughness properties in pipe. An overview of microstructure and property development with regard to various compositions has been outlined in the current paper. Microstructure and mechanical properties have been compared with X-80 plates produced using accelerated cooling.