Ultrahigh-intensity high-toughness X120 pipe line steel and manufacturing method thereof

Abstract

The present invention relates to one kind of high strength and high toughness X120 pipeline steel and its making process. The high strength and high toughness X120 pipeline steel consists of C 0.015-0.060 wt%, Mn 1.80-2.50 wt%, Si not more than 0.60 wt%, Ti 0.005-0.03 wt%, Al not more than 0.06 wt%, V not more than 0.15 wt%, B 0.0005-0.0030 wt%, P not more than 0.015 wt%, S not more than 0.003 wt%, Nb 0.043-0.150 wt%, N not more than 0.012 wt%, Cu not more than 0.80 wt%, Ni not more than 1.20 wt%, Cr not more than 1.20 wt%, Mo not more than 1.0 wt%, and Fe and impurity for the rest. Compared with available X80 pipeline steel, the high strength and high toughness X120 pipeline steel has 40 % higher strength and capacity of lowering pipeline constructing cost.

Description

technical field [0001] The invention relates to a pipeline steel and a manufacturing method thereof, in particular to an ultra-high-strength, high-toughness X120 pipeline steel and a manufacturing method thereof. Background technique [0002] In recent years, the changes in the energy structure and the increase in energy demand have greatly promoted the development of long-distance transmission pipelines. In order to improve transmission efficiency and reduce project investment, it has become a trend to develop steel for long-distance oil and gas transmission pipelines to high-grade steel. At present, the highest steel grade in the pipeline steel standards used by countries in the world is only X80 (yield strength greater than or equal to 555MPa). For example, CN1715434A discloses a high-strength and high-toughness X80 pipeline steel, the weight percent of its composition is: carbon 0.025-0.080%; silicon: 0.19-0.30%; manganese: 1.70-1.90%; titanium: 0.01-0.02%; : 0.015~0.0...

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Problems solved by technology

However, its strength does not meet the requirements of X120

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