High-strength X100 pipe line steel hot rolling flat plate and method for manufacturing same

Abstract

The invention discloses a high-strength X100 pipe line steel hot rolling flat plate and a method for manufacturing the same. The steel comprises the following chemical components in percentage by weight: 0.02 to 0.08 percent of C, 0.10 to 0.35 percent of Si, 1.65 to 2.20 percent of Mn, 0.005 to 0.020 percent of P, less than or equal to 0.003 percent of S, 0.04 to 0.11 percent of Nb, 0.008 to 0.030 percent of Ti, 0.02 to 0.045 percent of Als, one or more of less than or equal to 0.60 percent of Ni, less than or equal to 0.30 percent of Mo and less than or equal to 0.30 percent of Cu, and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps that: the heating temperature of a plate blank is between 1,160 and 1,280 DEG C, the rough rolling temperature is between 1,070 and 1,150 DEG C, the finish rolling temperature is between 830 and 950 DEG C, the finish cooling temperature is between 300 and 550 DEG C, and the controlled cooling speed is between 15 and 30 DEG C/S. By using the method, a complex phase structure mainly comprising the following bainites can be obtained. By adopting the complex phase structure, the yield strength of the pipe line steel hot rolling flat plate reaches 690 to 825MPa, the tensile strength reaches over 780MPa, the impact energy at a temperature of 20 DEG C below zero is more than or equal to 200J, and the shearing area of DWTT at a temperature of 15 DEG C below zero is more than or equal to 90 percent; and the rolling resistance and the straightening resistance are reduced, and the operating rates of the rolling machine and the straightening machine are improved.

Description

technical field [0001] The invention belongs to the controlled-rolling and controlled-cooling technology of low-carbon micro-alloy steel, and is mainly suitable for manufacturing X100 pipeline steel hot-rolled flat plates for high-pressure and large-diameter oil and gas pipelines and a production method thereof. Background technique [0002] Oil and gas pipelines are an important part of energy construction. With the development of world industry and the development of metallurgical technology, in order to reduce the cost of pipeline construction and operation, and improve the efficiency of oil and natural gas transmission, the transmission pipeline has rapidly developed to the direction of large pipe diameter and high pressure and high density of the transported medium. With X65 and X70 becoming the main steel grades of the main conveying line, X80 is also gradually expanding its application range. In order to meet the development requirements of medium to higher pressure,...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a high-strength X100 pipeline steel hot-rolled flat plate and its production method. On the basis of reducing the difficulty of smelting and reducing the difficulty of smelting,

Images