Large-wall-thickness X52MS acid-resistant pipeline steel plate produced by LF-RH refining process and manufacturing method thereof

Abstract

The invention relates to a large-wall-thickness X52MS acid-resistant pipeline steel plate produced by an LF-RH refining process. The steel plate is characterized by being manufactured from the following chemical component percentage by weight: 0.03%-0.07% of C, 0.2%-0.4% of Si, 1.0%-1.4% of Mn, 0.02%-0.04% of Al, 0.02%-0.05% of Nb, less than or equal to 0.02% of V, 0.004%-0.012% of Ti, 0.1%-0.4% of Cr, 0.1%-0.2% of Mo, less than or equal to 0.0005% of B, less than or equal to 0.012% of P, less than or equal to 0.001% of S, less than or equal to 0.005% of [N], less than or equal to 0.005% of [O], less than or equal to 0.0015% of [H] and the balance being Fe and inevitable impurities, wherein the cold crack sensitivity coefficient Pcm is less than or equal to 0.19. The manufacturing method comprises the sequential steps of KR molten iron pretreatment, converter smelting, LF and RH refining, plate blank continuous casting, plate blank heating, rough rolling, intermediate blank cooling, finish rolling, ACC cooling and the like. The manufactured steel plate has thickness being 35.1-44.2 mm, yield strength being 380-440 MPa, tensile strength being 490-570 MPa, and elongation being greater than or equal to 33%, yield ratio being less than or equal to 0.09; an average shear plane ratio of drop hammer under the temperature of minus 5 DEG C is 85% or more; and the large-wall-thickness X52MS pipeline steel can meet the requirement of being used in an acidic environment, and has good HIC resistance and low-temperature toughness.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a large-wall X52MS acid-resistant pipeline steel plate produced by an LF-RH refining process and a manufacturing method thereof. Background technique [0002] As the main transportation method of oil and gas resources, long-distance pipelines are widely used in onshore and submarine energy projects. In order to meet the requirements of high gas transmission capacity and safety, for the transmission medium containing hydrogen sulfide corrosive gas, the pipeline steel resistant to wet hydrogen sulfide corrosion is usually used. As the drilling area shifts to areas with harsh environments such as deserts and deep seas, the demand for large-wall acid-resistant pipelines is becoming more and more prominent, and product safety directly determines the design and implementation of the entire project. However, this type of pipeline steel is a large-thickness acid-resistant pipeline stee...

AI Technical Summary

Problems solved by technology

[0004] Patent announcement number CN108624811A proposes a large thick-walled acid-resistant and corrosion-resistant pipeline steel and its production method. The patented production process is the RH-LF refining process, which is different from the patented LF-RH refining process, and the design components It is very different from this patent. This patent only mentions the HIC resistance performance, and does not mention the drop hammer performance of large thick-walled acid-resistant and corrosion-resistant pipeline steel. Hammer average shear surface ratio ≥ 85%

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