X70QS seamless line pipe with HIC (Hydrogen Induced Cracking) resistance

Abstract

The invention provides an X70QS seamless line pipe with HIC (Hydrogen Induced Cracking) resistance, comprising the following components in weight by percentage: 0.06%-0.14% of C, 0.20%-0.45% of Si, 1.00%-1.30% of Mn, P not more than 0.015%, S not more than 0.003%, 0.05%-0.30% of Cr, 0.05%-0.30% of Mo, 0.015%-0.060% of Al, 0.003%-0.010% of N, 0.030%-0.050% of Nb, 0.05%-0.09% of V, not more than 0.10% of Ni, not more than 0.20% of Cu and the balance of Fe and impurities, wherein Ni and Cu which have limited content are residual element in the steel, the carbon equivalent CEpcm is not more than 0.22%, and CEIIW is not more than 0.39%. The X70QS seamless line pipe has the advantages of high strength and excellent impact performance and can ensure the impact power to be greater than 150J at -40 DEG C, which is much higher than the impact power standard values of the API (American Petroleum Institute) and the ISO (International Standards Organization); by controlling the CE and the PCM (Pulse-Code Modulation), the X70QS seamless line pipe qualitatively ensures better welding performance; the X70QS seamless line pipe has the advantages of high ductility, low yield ratio and high elongation; and the X70QS seamless line pipe has favorable HIC resistance, thereby ensuring that when the yield strength is greater than 485 MPa, the crack-sensitive rate CSR is not greater than 2%, the crack-length rate is not greater than 10%, and the crack-thickness rate CTR is not greater than 3%.

Description

technical field [0001] The invention relates to the field of corrosion-resistant materials and seamless pipes, in particular to high-grade, high-strength (≥485MPa) seamless line pipes with HIC resistance. Background technique [0002] In recent years, with the increasingly harsh conditions of oil and gas exploitation, the requirements for gathering and transportation pipelines necessary for exploitation have been continuously improved, not only the requirements for steel grades have increased, but also the properties of materials have been improved to meet the requirements of conveying media and processes. Variety. Pipelines with HIC resistance are the materials with the highest performance requirements among pipeline steels. The products are required to have ultra-low sulfur content, shape control of inclusions, uniform structure, and low hardness. The composition process design of this type of steel, Both the control level of smelting and rolling put forward very high req...

AI Technical Summary

Problems solved by technology

CN1914341A discloses "Pipeline steel with excellent HIC resistance and pipeline pipe made of this steel". In this invention, the composition range of C, Mn, etc. affecting strength is too wide, and there is no clear steel grade

High-strength (≥485MPa) seamless line pipes with HIC resistance have not been reported yet

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