X130 pipe line steel with low yield ratio and ultrahigh strength and manufacturing method of hot rolled flat plate of X130 pipe line steel

Abstract

The invention relates to X130 pipe line steel with low yield ratio and ultrahigh strength and a manufacturing method of a hot rolled flat plate of the X130 pipe line steel. The X130 pipe line steel comprises the following components: 0.030-0.090 percent of C, 1.50-2.50 percent of Mn, 0.10-0.60 percent of Si, not more than 0.015 percent of P, not more than 0.003 percent of S, 0.040-0.150 percent of Nb, 0.005-0.03 percent of Ti, 0.01-0.06 percent of Alt, not more than 0.012 percent of N, one or two of 0-1.20 percent of Cu and 0-1.20 percent of N, one or two of 0-1.20 percent of Cr and 0-1.20 percent of Mo, and the balance of Fe. The manufacturing method disclosed by the invention comprises the following steps of: smelting, external refining, casting and hot rolling, wherein the heating temperature of a plate blank is 1050-1280 DEG C, the controlled rolling temperature of a recrystallized zone is 900-1250 DEG C, the controlled rolling temperature of a non-recrystallized zone is 700-950 DEG C, the final rolling temperature is 700-880 DEG C, the final cooling temperature is 150-500 DEG C, and the cooling temperature is 3-35 DEG C / s. According to the manufacturing method disclosed by the invention, the hot rolled flat plate of which the yield strength is more than 900MPa and the yield ratio is not higher than 0.90 is produced without adding V and B and using a subsequent thermal treatment process.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and in particular relates to an ultra-high-strength low-yield ratio X130 pipeline steel and a method for manufacturing the hot-rolled flat plate thereof. Background technique [0002] In recent years, the changes in energy structure and the increase in energy demand have greatly promoted the development of long-distance oil and gas transmission pipelines. In order to improve transmission efficiency and reduce engineering investment, it has become an inevitable trend to develop steel for long-distance oil and gas transmission pipelines to high-grade steel. [0003] Under the same transportation conditions, the application of high-grade pipeline steel products can reduce the wall thickness of steel pipes, save steel consumption, reduce engineering investment and improve construction efficiency; or increase the transportation pressure under the condition of constant pipe diameter and wall th...

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Problems solved by technology

The high-strength pipeline steel patents that have been published at home and abroad have low yield strength and cannot meet the requirements of X130. For example, the hot-rolled steel plates and their preparation methods described in the WO2008054166 patent and CN101165203 patent can only meet the strength requirements of X120; The strength meets the requirements, but the yield strength ratio is high, exceeding 0.90, even reaching 0.98, which is not conducive to the engineering application of high-strength pipeline steel, such as the JP2002285283 patent; although some strengths can reach more than 900MPa, they need to be processed for hot-rolled plates. Heat treatment increases manufacturing cost and process complexity. For example, US5900075 patent describes a pipeline steel that requires heat treatment to promote Cu precipitation hardening

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