Structure and Properties of Nb-Ti Compound Micro-alloyed X60 Steel for Linepipe Purpose as Produced with CSP Process

Tested and analyzed are the structure and properties of the Nb-Ti compound micro-alloyed X60 steel for linepipe purpose as produced with the CSP (Compact Strip Production) process. The result demonstrates that compared with the similar products as made with the conventional processes, the said CSP process-produced X60 steel possesses such properties as slight differences between the properties in different directions, e.g., the differences of both tensile strength and yield strength between the transversal and the longitudinal are ≤15 MPa, and excellent fracture toughness and HIC and SSCC resistances. The properties of the HFW pipe made of the said steel are: PF +P structure of both the weld seam and the heat-affected area, average impact value: 109 J and in- sensitivity to the stench-shaped corrosion, etc.