Acid-corrosion-resistant X70MS pipeline steel hot rolled coil and manufacturing method thereof

Abstract

The invention provides an acid-corrosion-resistant X70MS pipeline steel hot rolled coil and a manufacturing method thereof. The acid-corrosion-resistant X70MS pipeline steel hot rolled coil comprisesthe following components including, by mass, 0.03% to 0.10% of C, 1.10% to 1.40% of Mn, 0.10% to 0.20% of Si, 0.010% to 0.030% of Al, 0.15% to 0.55% of Cr, 0.15% to 0.45% of Mo, 0.005% to 0.025% of Ti, 0.050% to 0.080% of Nb, 0.020% to 0.040% of V, 0.15% to 0.30% of Ni, not larger than 0.0002% of B, not larger than 0.012% of P, not larger than 0.0020% of S, not larger than 0.0060% of N, not largerthan 0.0018% of O, not larger than 0.0005% of H and the balance Fe and inevitable inclusions. Compositions and mechanical property of the acid-corrosion-resistant pipeline steel X70MS products meet the API 5L standard, the acid corrosion resistance performance meets international HIC resistant and SSCC resistant related standard requirements, the good welding technology performance is obtained, and the requirements for producing materials for oil and gas pipelines are met.

Description

technical field [0001] The invention relates to the field of metal smelting, in particular to an acid corrosion-resistant X70MS pipeline steel hot-rolled coil and a manufacturing method thereof. Background technique [0002] Acid-resistant pipeline steel is mainly used to transport oil and gas pipelines rich in acidic media. The main demand is for export and oil and gas field gathering and transportation pipelines in southwest China and other places. With the increase of oil and gas resource development, the quality of oil and gas in the world has been declining in recent years Trend, Cl in oil and gas - , SO 4 2- iso-salt content and CO 2 The content of acidic substances such as sulfide and sulfide increases. At the same time, the application of ultra-large pipe diameter and high-pressure conveying technology increases the erosion corrosion and corrosion fatigue of pipeline steel fluid, which puts forward higher requirements for the strength and corrosion resistance of p...

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Problems solved by technology

[0003] Affect the resistance of ordinary acid corrosion X70MS pipeline steel to H 2 The main factors of S corrosion are not yet clear. Through a large number of experiments, research and analysis of H 2 The relationship between S corrosion and alloy composition, microstructure, banded structure, second phase hard phase in steel and segregation, it was found that the banded structure is resistant to H in pipeline steel 2 S corrosion has a great influence. Ordinary X70 pipeline steels serve in acidic medium environments, and hydrogen-induced cracking and stress corrosion cracking will occur; high-level corrosion-resistant pipeline steels need to add a large amount of Cu, Cr, and Ni elements to improve the corrosion resistance Corrosion resistance increases the cost of the alloy. Therefore, it is necessary to optimize the composition design of the acid corrosion resistant X70MS pipeline steel, improve the composition of elements in the steel, save the cost of the alloy, and at the same time improve the smelting process of molten steel, improve the purity of molten steel, and reduce the microstructure. Segregation, and make the acid corrosion resistant X70MS pipeline steel have higher acid corrosion resistance

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