Submarine seamless line pipe above 415SPDF steel grade having large strain resistance

Abstract

The invention provides a submarine seamless line pipe above 415SPDF steel grade having large strain resistance. The submarine seamless line pipe comprises the following components, by weight, 0.05-0.11% of C, 0.20-0.40% of Si, 1.0-1.40% of Mn, less than or equal to 0.010% of P, less than or equal to 0.002% of S, 0.05-0.30% of Ni, 0.05-0.30% of Cr, 0.05-0.30% of Mo, 0.010-0.050% of Als, less than or equal to 0.010% of N, 0.010-0.050% of Nb, 0.03-0.08% of V, 0.05-0.25% of Cu, 0.008-0.030% of Ti, less than or equal to 0.020%of Pb, less than or equal to 0.020% of Sn, less than or equal to 0.030% of As, less than or equal to 0.015% of Sb, less than or equal to 0.015% of Bi, less than or equal to 0.0005% of B, less than or equal to 0.22% of carbon equivalent CEpcm, less than or equal to 0.39% of CEIIW, and less than or equal to 0.8% of a total amount of Ni, Mo, Cr and Cu that are added to Ni, Mo, Cr and Cu alloys. The submarine seamless line pipe has the benefits that after three times of pull-down circulation under 3% strain, the strength of the submarine seamless line pipe can be ensured to be greater than 415MPa, and ballistic work at minus 20 degrees of the submarine seamless line pipe can be ensured to be greater than 300J; the submarine seamless line pipe has less than or equal to 1.5% of crack sensitivity ratio (CSR), less than or equal to 5% of crack length ratio, and less than or equal to 3% of crack thickness ratio (CTR); and the submarine seamless line pipe does not break under 100% loading for 96h by an SSCB method.

Description

technical field [0001] The invention relates to the field of designing corrosion-resistant materials and seamless pipes based on strain, in particular to seabed seamless line pipes of steel grade above 415SPDF with large strain resistance. Background technique [0002] With the increasingly harsh conditions of offshore oil and gas exploitation, the depth of drilling and production has increased year by year, and more and more deep sea mining has been conducted. Shallow sea mining methods can no longer fully meet the demand. At the same time, the shallow sea pipe laying method can no longer meet the needs of deep sea development. With the change of mining conditions, the traditional S-lay laying is gradually transformed into R-lay laying. In addition to the conventional tensile properties, impact properties and hardness requirements, the R-lay line pipes also require good resistance to large strains, fracture toughness and brittleness, corrosion resistance and good geometric...

AI Technical Summary

Problems solved by technology

Submarine seamless line pipes with high strength (≥415MPa) large strain resistance and 3 times of 3% tension and compression cycles have not been reported

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