Flat plate for high-plasticity thick-wall deep sea pipeline and production method thereof

Abstract

The invention discloses a flat plate for a high-plasticity thick-wall deep sea pipeline and a production method of the flat plate. The steel contains 0.030%-0.055% of C, 0.16%-0.30% of Si, 1.36%-1.65%of Mn, 0.04%-0.07% of Nb, 0.008%-0.025% of Ti, 0.11%-0.24% of Cu, 0.10%-0.20% of Cr, 0.015%-0.040% of Als, 0.0021%-0.0049% of N, smaller than or equal to 0.010% of P, smaller than or equal to 0.0015%of S, 0.0015%-0.0045% of Ca, smaller than or equal to 0.00015% of H, smaller than or equal to 0.0020% of O, smaller than or equal to 0.14% of Ni, smaller than or equal to 0.15% of Mo, 0.31%-0.50% ofMo+Ni+Cr+Cu, and the balance of Fe and inevitable impurities. The casting blank heating process is divided into four stages, and the rough rolling temperature is 1050-1150 DEG C. The total deformationrate is larger than or equal to 51%, and the finish rolling temperature is 800-890 DEG C. The final cooling temperature is 350-430 DEG C. A produced steel plate has good plasticity, low-temperature toughness and low yield ratio.

Description

technical field [0001] The invention belongs to the technical field of low-carbon and low-alloy pipeline steel production, and in particular relates to a X65 and X70-grade high-plasticity, low-yield-ratio, and corrosion-resistant subsea pipeline plate with a thickness ≥ 33 mm for deep-sea oil and gas transportation and a production method thereof. Background technique [0002] With the depletion of land oil and gas resources, the focus of oil and gas exploitation has gradually shifted to the sea. Offshore oil and gas resources are an important part of global oil and gas resources and have great development potential. my country's seabed oil and gas reserves are very rich. There are huge oil and gas reserves in the Bohai Sea, the East China Sea, and the South China Sea. The South China Sea alone is as high as 23 billion to 30 billion m 3 . [0003] Submarine pipelines are important facilities for offshore oil and gas transportation. In view of the laying method and harsh s...

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Problems solved by technology

[0013] The purpose of the present invention is to overcome the deficiencies of the prior art, to solve the control problems of deep-sea thick-wall pipeline steel plasticity, drop hammer performance, structure uniformity, and corrosion resistance, and to provide a deep-sea oil and gas transportation with a thickness ≥ 33mm X65, X70 High plasticity, high toughness, low yield ratio, corrosion-resistant deep-sea pipeline plate and production method thereof

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