High-strength marine riser steel and production method

Abstract

High-strength marine riser steel comprises chemical components in percentage by weight as follows: 0.050%-0.075% of C, 0.10%-0.30% of Si, 0.50%-1.00% of Mn, less than or equal to 0.015% of P, less than or equal to 0.0040% of S, 0.45%-0.90% of Cu, 0.30%-0.50% of Cr, 0.25%-0.50% of Ni, 0.10%-0.40% of Mo, 0.010%-0.030% of Nb, 0.010%-0.025% of Ti, 0.010%-0.050% of Al and less than or equal to 0.008% of N. The production method comprises steps as follows: heating after a blank is formed through continuous casting; rough rolling; finish rolling; cooling; straightening; heat treatment. The ideal fine-grained tempered sorbite structure can be obtained in the plate thickness direction, good matching of excellent strength, plasticity, toughness and fatigue properties required by the high-strength marine riser steel can be realized, and a steel plate has the Rt0.5 larger than or equal to 555 MPa, Rm larger than or equal to 625 MPa, KV2 larger than or equal to 200 J at the temperature of subzero 30 DEG C, DWTT SA larger than or equal to 85% at the temperature of subzero 15 DEG C and CTOD larger than or equal to 0.50 mm at the temperature of subzero 10 DEG C.

Description

technical field [0001] The invention relates to a steel for pipelines and a production method, in particular to a steel for risers and a production method thereof, specifically to steel for high-performance risers suitable for deep seas with a sea depth below 500 meters and a production method thereof. Background technique [0002] With the gradual depletion of land oil and gas resources, new resource exploitation extends to areas with harsh geological conditions such as oceans and polar regions. At present, it has been proven that the world's offshore oil resources account for 34% of the world's total oil resources, and the annual production of offshore natural gas has reached 32% of the world's total annual natural gas production. More than 100 countries around the world are conducting offshore oil exploration, of which More than half of the deep sea and ultra-deep sea areas have been explored for oil. Therefore, the importance of steel for offshore oil and gas development...

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide a kind of R t0.5 ≥555MPa,R m ≥625MPa, -30℃KV 2 ≥200J, -15°C DWTTSA≥85%, -10°C CTOD≥0.50mm shallow sea riser steel and its production method

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