An economical thick-walled high-strength toughness x70m hot-rolled steel plate and its manufacturing method

Abstract

The invention relates to an economical thick-walled high-strength toughness X70M hot-rolled steel plate and a manufacturing method thereof. The chemical composition of the steel plate is calculated by weight percentage: C 0.045%-0.09%, Si 0.10%-0.35%, Mn 1.50%-1.85% , P≤0.01%, S≤0.015%, Nb 0.04%~0.09%, Ti 0.008%~0.0250%, Al 0.015%~0.045%, Cr 0.25%~0.5%, Cu 0.15%~0.55%, Zr 0.02%~ 0.04%, N 0.0041% to 0.006%, and the balance is Fe and unavoidable impurities; the steel plate of the present invention is suitable for manufacturing oil and gas transmission straight seam welded pipes with a pipe diameter of 25 to 38 mm in wall thickness, and solves the problem of rolling in the steel plate production process. It has high strength, high toughness and good comprehensive performance due to the problems of high resistance to resistance, high straightening resistance and poor uniformity of steel plate properties.

Description

technical field [0001] The invention relates to the technical field of low-carbon micro-alloy steel production, in particular to an economical thick-walled high-strength and toughness X70M hot-rolled steel plate and a manufacturing method thereof. Background technique [0002] Pipeline transportation is the most economical, most convenient and most important transportation method for long-distance transportation of oil and gas. Thick-gauge line pipe is mainly used in areas with special requirements and harsh environments such as large-capacity oil and gas pipelines and pipelines passing through seismic zones. With the development of oil and gas resources from inland to polar regions, from land to sea, from shallow sea to deep sea, and the development of large-scale pipeline transportation, large-diameter thick-walled line pipes will be widely used in oil and gas pipeline construction, and have good applications prospect. [0003] In order to improve the operational safety,...

AI Technical Summary

Problems solved by technology

[0010] The invention provides an economical thick-walled high-strength toughness X70M hot-rolled steel plate and its manufacturing method, which is suitable for manufacturing pipe diameters of Longitudinal welded pipes for oil and gas transportation with a wall thickness of 25-38 mm can meet the technical requirements of ultra-wide X70M steel plates without subsequent off-line heat treatment and stacking and slow cooling, and solve the problem of large rolling resistance, large straightening resistance and uniform properties of steel plates in the production process of steel plates The steel plate produced has high strength, high toughness and good comprehensive performance, which can ensure the safety of oil and gas pipelines

Images