Effect of hot Rolling and Cooling Conditions on the Microstructure, MA Constituent Formation, and Pipeline Steels Mechanical Properties

Abstract

Two types of pipeline steels differentiated by the content of aluminum and silicon are produced during the pilot plant test with varying rolling temperature and accelerated cooling rate. Microstructures, MA constituent morphology, and mechanical properties of such materials are compared using digital and electron microscopy, tensile, and Charpy impact tests. Results show that low finishing rolling temperature stimulates MA constituent refinement. Cooling rate increase leads to MA constituent amount increase and refinement. Alloying with aluminum significantly stabilizes austenite and leads to MA constituent amount and size increase. Higher MA constituent amount has in most cases positive effect on plasticity without strength and impact toughness degradation.