Ultra-wide high-toughness hot-rolled thick plate for low-temperature pipeline, and production method thereof

Abstract

The invention discloses an ultra-wide high-toughness hot-rolled thick plate for a low-temperature pipeline, and a production method thereof. The steel is prepared from 0.030 percent to 0.055 percent of C, 0.16 percent to 0.30 percent of Si, 1.45 percent to 1.70 percent of Mn, 0.04 percent to 0.07 percent of Nb, 0.012 percent to 0.025 percent of Ti, 0.20 percent to 0.40 percent of Cr, less than orequal to 0.14 percent of Mo, less than or equal to 0.20 percent of Ni, less than or equal to 0.15 percent of Cu, less than or equal to 0.030 percent of Al, less than or equal to 0.010 percent of P, less than or equal to 0.0015 percent of S, 0.0005 percent to 0.0020 percent of O, 0.001 percent to 0.004 percent of N, 0.0010 percent to 0.0045 percent of Ca, larger than or equal to 1.8 percent of Ca/S, 0.30 percent to 0.60 percent of (Mo+Ni+Cr+Cu), and the balance Fe and inevitable impurities. The rough rolling starting temperature is 1080 to 1130 DEG C, the finish rolling temperature is 980 to 1030 DEG C, the precision rolling starting temperature is 820 to 860 DEG C, the precision rolling finish rolling temperature is 740 to 760 DEG C, the cooling speed is 8 to 15 DEG C/s, and the hot straightening speed is 0.7 to 1.2m/s. The finished product steel plate has the thickness being larger than or equal to 21mm and the width being larger than 4300mm, and has excellent low-temperature toughness.

Description

technical field [0001] The invention belongs to the technical field of low-carbon low-alloy steel, in particular to a L485-grade ultra-wide, high-toughness, low-yield ratio, high-plastic hot-rolled thick plate with a thickness ≥ 21 mm and a width > 4300 mm for low-temperature environment oil and gas transmission pipelines and its production method. Background technique [0002] In today's world, the demand and consumption of oil, natural gas and other energy sources are constantly increasing, requiring oil and gas pipelines to continue to develop in the direction of high efficiency and economy under the premise of ensuring safety. Increasing the pipe diameter and delivery pressure is an important measure to improve the transmission efficiency. Among them, the effect of increasing the pipe diameter is more significant. At the same time, in order to ensure safety, the wall thickness and steel grade of oil and gas pipelines are also increasing. For raw materials, the corres...

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Problems solved by technology

[0012] The purpose of the present invention is to overcome the deficiencies of the prior art and solve the comprehensive performance matching problems of ultra-wide hot-rolled thick plates for low-temperature pipelines such as strength, plasticity, low-temperature toughness and strain resistance, as well as the problems...

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