Steel plate for producing seabed pipe line and rolling method therefor

Abstract

The present invention relates to steel plate for making submarine pipeline and its rolling process. The steel plate has the chemical components including C 0.030-0.075 wt%, Si 0.10-0.30 wt%, Mn 1.40-1.60 wt%, P not more than 0.015 wt%, S not more than 0.003 wt%, Cu not more than 0.20 wt%, Ni 0.10-0.25 wt%, Mo 0.07-0.20 wt%, Nb 0.03-0.05 wt%, V not more than 0.060 wt%, Ti 0.001-0.02 wt%, Al 0.01-0.06 wt%, Cr not more than 0.20 wt%, N not more than 0.009 wt%, Ca 0.001-0.005 wt%, B not more than 0.0005 wt%, Sn not more than 0.010 wt%, As not more than 0.030 wt%, and Fe for the rest. The steel plate has high cleanliness, high strength and high toughness, and is used in producing submerged arc welded submarine pipeline.

Description

technical field [0001] The invention relates to a steel plate and a rolling method thereof, in particular to a steel plate for making a submarine pipeline and a rolling method thereof. Background technique [0002] With the rapid development of the national economy, the demand for oil and natural gas is in short supply, which has greatly promoted the development of marginal oil and gas fields and offshore oil and gas resources and the construction of submarine pipelines. The importance of steel for submarine pipelines has become increasingly prominent. [0003] The harsh marine environment puts forward stricter quality requirements for steel for submarine pipelines than for steel for land pipelines. Due to the influence of factors such as side bending and changes in seabed currents during the laying process, seabed pipeline steel is required to have high cleanliness, high longitudinal strength, high toughness, low steel plate anisotropy and additional crack arrest evaluation...

AI Technical Summary

Problems solved by technology

The production of hot continuous machine has the advantages of high production efficiency and high dimensional accuracy, but the anisotropy of hot continuous rolling is large, and at the same time, due to the work hardening and hot rolling stress in the process of flattening and cross cutting, it is difficult to release, resulting in poor shape of the steel plate, The performance changes greatly, so the production of high-strength (ReL ≥ 450MPa) steel plates for submarine pipelines is the goal of metallurgical enterprises to meet the growing demand for the development of marginal oil and gas fields and offshore oil and gas resources.

[0005] Chinese patent application No. 200510023651 discloses a "X65 pipeline steel for acidic environment and its manufacturing method". The application environment is acidic environment, not suitable for harsh marine environment. For the steel used for seabed longitudinal submerged arc welded pipes, the alloy design and production process need to be redesigned

[0006] Pipeline steel, especially submarine pipeline steel is currently the most active technical field of research, and its research results have also been partially reported. The relevant literature includes "Development and Application of Submarine Pipeline Steel" (Welded Pipe. 2006, 29(5): 36-39), introduced the physical and chemical properties of Baosteel's X65 grade steel plate for submarine pipelines, but the literature did not fully disclose the chemical composition of the steel and its production method