Hot-rolled wide and thick plate with good ductility and toughness for low temperature pipelines and manufacturing method thereof

Abstract

The invention provides a hot-rolled wide and thick plate with good ductility and toughness for low temperature pipelines and a manufacturing method thereof. The steel plate comprises the following components in percentage by weight: 0.035 to 0.060% of C, 0.20 to 0.35% of Si, 1.56 to 1.74% of Mn, 0.01 to 0.04% of Nb, 0.011 to 0.025% of Ti, 0.18 to 0.30% of Cr, 0.06 to 0.15% of Ni, 0.015 to 0.040% of Als, 0 to 0.10% of Cu, 0 to 0.19% of Mo, 0.0020 to 0.0045% of N, not more than 0.009% of P, not more than 0.001% of S, not more than 0.0015% of H, not more than 0.0020% of O, and the balance being iron and inevitable impurities; wherein the total percentage of Mo, Ni, Cu, and Cr is in a range of 0.32 to 0.55%, and the ratio of Ti and N is in a range of 3.42 to 6.10. At the same time, CEIIW is controlled in a range of 0.385 to 0.430%, and CEPcm is controlled in a range of 0.159 to 0.175%. The manufacturing method comprises steps of molten iron pretreatment, converter smelting, external refining, continuous casting, casting blank reheating, rolling, and cooling. The provided wide and thick plate can be used as a raw material to prepare large diameter (not less than 1420 mm) thick wall low temperature steel pipelines, and the ductility and toughness are good.

Description

technical field [0001] The invention belongs to the field of low-carbon and low-alloy steels, and in particular relates to a hot-rolled wide-thick steel plate with good plasticity and toughness for low-temperature pipelines used for oil and gas transportation and a manufacturing method thereof. Background technique [0002] With the continuous increase of world oil and natural gas consumption and the gradual depletion of existing oil and gas fields, new oil and gas projects continue to develop in remote and harsh climate areas, such as Russia, Alaska and other alpine regions are one of the key development directions. Due to the harsh service conditions of the pipeline in the alpine region, it is required that the pipeline must not only achieve the corresponding strength, but also have good ductility and low temperature toughness; at the same time, in order to improve the transmission efficiency, the transmission pressure and the diameter of the pipeline are constantly increas...

AI Technical Summary

Problems solved by technology

[0007] "A Thick-Walled High DWTT Performance X65-X70 Submarine Pipeline Steel and Its Manufacturing Method" (CN103834874A) discloses that the composition of the X65-X70 submarine pipeline steel is (percentage by weight) C: 0.03% to 0.05%, Mn: 1.47% to 1.70% , Ni: 0.36% ~ 0.45%, Cu: 0.12% ~ 0.20%, the disadvantage is that more alloy elements such as Ni are also added to ensure performance

[0012] To sum up, the research on hot-rolled wide and thick steel plates with good plasticity and toughness for pipelines in low-temperature regions is still insufficient in the prior art.

Images