High-strength pipeline steel for petroleum and manufacturing method of pipeline steel

Abstract

The invention provides high-strength pipeline steel for petroleum and a manufacturing method of the pipeline steel, and the high-strength pipeline steel for the petroleum and the manufacturing methodof the pipeline steel is characterized by comprising the following components of, by weight, 0.045-0.05% of C, 0.05%-0.15% of Si, 1.2-1.5% of Mn, less than or equal to 0.015% of P, less than or equalto 0.005% of S, 0.01-0.015% of V, 0.07-0.08% of Nb, 0.010-012% of Ti, less than or equal to 0.050% of Al, 0.65-0.75% of Cr, 0.55-0.65% of Mo, 0.1-0.15% of Ni, 0.05 -0.06% of Cu, 0.005-0.008% of W, 0.0001-0.0005% of rare earth (Hf+La), 0.0001-0.005% of B, 0.001-0.005% of N, 3.42-5.5 Ti / N, and the balance Fe and inevitable impurity elements; a final tissue of the acicular ferrite with the area rateis counted as 92-94% and the final tissue of the martensite with the area rate is counted as 6-8%, electron microscope detection is carried out, wherein the average range of the formed TiN grain sizeis 20-30 nanometers, the area rate is 0.5-1%; and meanwhile, the cold cracking sensitivity index Pcm is also required to be in the range of 18-0.28%; the process route comprises the following steps ofproportioning material preparation, molten iron pretreatment, molten steel smelting, secondary refining, continuous casting, rolling and reeling.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and in particular relates to a high-strength petroleum pipeline steel and a preparation 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. 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.

[0004] 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

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