X80 and below steel grade pipeline steel for deep-sea drilling marine riser and preparation method thereof

Abstract

The invention relates to X80 and below steel grade pipeline steel for a deep-sea drilling marine riser which comprises the chemical components in percentages by mass: 0.04-0.08% of C, 1.7-1.85% of Mn, 0.25-0.45% of Si, less than or equal to 0.001% of S, less than or equal to 0.010% of P, 0.02-0.04% of Nb, 0.008-0.03% of Ti, 0.01-0.06% of V, less than or equal to 0.06% of Alt, less than or equal to 0.010% of N, less than or equal to 0.006% of O, less than or equal to 0.30% of Mo, less than or equal to 0.30% of Cu, 0.15-0.35% of Ni, 0.15-0.45% of Cr, less than or equal to 0.01% of Ca and the balance of Fe and inevitable impurities. A steel plate smelting process route is as follows: material preparation; converter or electric furnace smelting; external refining; continuous casting; slab reheating; special TMCP process; and air cooling to room temperature. The steel provided by the invention can obviously improve the mechanical property of the deep-sea drilling marine riser.

Description

technical field [0001] The invention relates to the technical field of risers for deep-sea drilling, in particular to an X80 pipeline steel with uniform vertical and horizontal strength and double hardness requirements and a manufacturing method thereof. The invention is also applicable to pipeline steels below the X80 steel grade. Background technique [0002] At present, fossil energy still occupies a dominant position in the energy structure in the energy demanded by the world. In recent years, the rapid growth of the world economy has greatly driven the rapid growth of fossil energy demand. . Energy extraction has turned to the sea. Steel for marine pipelines involves the fields of oil drilling and oil transportation. Due to the high pressure in the deep sea and the influence factors such as ocean currents during drilling, it is usually necessary to use high-grade thicker steel plates to make deep-sea risers during drilling to ensure smooth drilling operations. Consid...

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Problems solved by technology

However, this method: 1) only mentions the longitudinal tensile properties, but does not mention the transverse tensile properties, the uniformity of the longitudinal and transverse tensile strengths, and the processes that need to be adopted; The surface hardness requirements required for the surface of the riser to be scoured by the ocean mud flow brought up during drilling

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