Patent ID: 9249486
Filing Date: 2016-02-02
CPC Classification: C21D,C22C

Claim Text:
1. A profiled wire of hydrogen-embrittlement-resistant, low-alloy carbon steel for flexible pipelines for the offshore oil and gas operations sector, comprising: a chemical composition, expressed in percentages by weight of the total mass, and in that, starting from a wire rod, hot-rolled in its austenitic region above 900° C. then cooled to ambient temperature, and then having a diameter of approximately 5 to 30 mm, it is obtained by subjecting the said starting wire rod first to a thermomechanical treatment according to two successive and ordered steps, specifically isothermal quenching, which confers on it a homogeneous pearlitic microstructure, following by an operation of cold mechanical transformation, carried out with a global work-hardening ratio of between approximately 50 and 80% maximum, to give the wire its final profile, and in that the profiled wire obtained in this way is then subjected to a short-duration recovery heat treatment carried out below the Ac 1 temperature of the steel with a temperature of between 410 and 710° C. for a duration not exceeding one minute.