Manufacturing method of pipeline steel with high strength and toughness and high deformability

Abstract

The invention discloses a manufacturing method of pipeline steel with high strength and toughness and high deformability. The steel comprises the following components in percentage by weight: 0.01-0.06% of C, 0.05-0.55% of Si, 1.60-2.00% of Mn, not more than 0.012% of P, not more than 0.005% of S, not more than 0.11% of Nb, not more than 0.06% of V, not more than 0.025% of Ti, not more than 0.0080% of N, not more than 0.50% of Cu, not more than 0.50% of Cr and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: performing pretreatment of molten iron, smelting, refining and continuous casting to prepare a plate blank comprising the components in percentage by weight, being in line with the requirements; and manufacturing a steel plate through thermal mechanical control of rolling and control of cooling process so as to get the pipeline steel. The pipeline steel disclosed by the invention is very small in crystal grains and appropriate in soft phase-hard phase proportion and can get higher strength and toughness and excellent deformability under the situation of not containing Ni, Mo and other alloy elements and containing lower C content. The tensile strength Rm is not less than 695 and not more than 990, the yield ratio Rp0.2 / Rm is not more than 0.8, the uniform deformation elongation rate is not less than 5%, and the Charpy impact energy is not less than 300J. The pipeline steel disclosed by the invention is low in cost, and the obtained steel plate has the advantages of excellent deformability, strength, toughness and excellent welding performance.

Description

technical field [0001] The invention belongs to the field of iron and steel material manufacturing, and relates to a pipeline steel, in particular to a pipeline steel with high strength, toughness and high deformation capacity and a preparation method thereof. Background technique [0002] With the construction of the second line of natural gas pipelines for the West-East Gas Pipeline, my country has made significant progress in the development and application of X80 high-strength pipeline steel pipes. At present, my country has planned to lay a test section with high steel grade and high transmission pressure on the third line of the West-East Gas Pipeline. This will drive the continuous improvement of X90, X100 and other higher-grade pipeline steel manufacturing technologies, and thus will promote the mass production and application of my country's high-grade welded pipes, and usher in a new era in the manufacture of my country's oil and gas pipeline steel. A round of orga...

AI Technical Summary

Problems solved by technology

[0005] Grain refinement can improve the strength and toughness of pipeline steel at the same time, but the effect of traditional TMCP grain refinement is limited, and it can only reach about 10 μm

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