Medium plate for large-wall thick submerged pipeline steel and production method of medium plate

Abstract

The invention discloses a medium plate for large-wall thick submerged pipeline steel and a production method of the medium plate, belonging to the technical field of low-carbon microalloyed steel. The medium plate comprises the following components in percentage by weight: 0.025-0.045% of C, 0.10-0.35% of Si, 1.10-1.40% of Mn, less than or equal to 0.015% of P, less than or equal to 0.003% of S, 0.04-0.07% of Nb, less than or equal to 0.06% of V, 0.010-0.020% of Ti, 0.15-0.40% of Ni, less than or equal to 0.20% of Cr, less than or equal to 0.08% of Mo, 0.010-0.040% of Al, more than or equal to 2% of Al / N, and the balance of Fe and inevitable impurities. The method comprises the steps of blast furnace molten iron smelting, molten iron pre-desulfurization, smelting in a converter, LF+RH refining, plate blank continuous casting, plate blank heating, rolling in a 4300-type rolling mill, ACC quick cooling, cooling in heap, sampling, inspection, warehousing and dispatching. The medium plate has the advantages of stable mechanical property index, good medium plate and toughness matching property and excellent corrosion resistance.

Description

technical field [0001] The invention belongs to the technical field of low-carbon micro-alloy steel, and in particular relates to a medium-thick plate for seabed pipeline steel with large wall thickness and a production method with low cost and suitable for seabed oil and gas transmission pipelines. Background technique [0002] With the rapid development of the world economy and the depletion of terrestrial energy resources, offshore oil and gas exploration has become an upsurge, and pipeline construction extends to areas with harsh environments such as oceans, seismic zones, and polar frozen land. At present, more than 100 countries in the world are conducting offshore oil and gas exploration, more than half of which are in the deep sea. Limited by exploration, laying, testing, pipeline raw material technology and equipment conditions, the development of oil and gas resources in deep sea areas in my country is in its infancy. Only the deep sea pipelines of the Liwan projec...

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Problems solved by technology

Another example is the patent of CN102409224, which is entitled "Hot-rolled steel plate for thick-gauge submarine pipeline with excellent low-temperature toughness and its production method", and its chemical composition weight percentage is C: 0.02% to 0.07%, Si: 0.15% to 0.40%, Mn : 1.0%~1.70%, P: ≤0.020%, S≤0.003%, Nb≤0.06%, Ti≤0.025%, V≤0.06%, Mo≤0.20%, Cu≤0.25%, Ni: 0.10%~0.30% , Cr ≤ 0.25%, N ≤ 0.008%, Al: 0.010% ~ 0.040%, Al / N ≥ 2, the thickness of the steel plate produced is 28-36mm, but the Mo and Ni alloys are relatively high

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