材料期刊网

In this study, two API X80 pipeline steels were fabricated by varying Ti additions, and their microstructures and fracture characteristics were analyzed to investigate the effects of Ti-enriched carbonitride on the tensile properties and Charpy impact properties. Lathy bainite, a mass of matensite/austenite (M/A), coarse cubic Ti-enriched inclusions, chain-typed Ti-enriched precipitations, weak toughness and high tensile strength were found as consequences of higher amount of Ti content. Those large scale and chain-typed Ti-enriched carbonitrides are one kind of crack sources during fracture. The negative e®ect of higher amount of Ti on the impact properties is increased with decreased temperature.