Acid-corrosion-resistant X70 pipeline steel plate and manufacturing method thereof

Abstract

The invention belongs to the technical field of smelting, in particular relates to an acid-corrosion-resistant X70 MS pipeline steel plate, and further relates to a manufacturing method of the steel plate. The steel plate comprises the following ingredients in percentage by weight: 0.03-0.06 percent of C, 0-0.04 percent of Si, 1.30-1.70 percent of Mn, at most 0.008 percent of P, at most 0.0010 percent of S, 0.030-0.050 percent of Nb, 0.010-0.025 percent of Ti, 0.10-0.35 percent of Mo, 0.10-0.35 percent of Cu, 0.15-0.35 percent of Cr, 0.15-0.30 percent of Ni, 0.020-0.035 percent of Al, at most 0.0045 percent of N, at most 0.00015 percent of H, at most 0.0025 percent of O and the balance of Fe, wherein H+O+N+P+S is at most 150ppm. The manufacturing method overcomes the problems of poor dynamic tearing toughness at low temperature and poor uniformity of thickness and structure of thick pipeline steel and can manufacture the X70 MS pipeline steel plate which is stable in performance and has HIC and SSCC resistance and low-temperature dynamic tear resistance. The steel plate is good in cold formability and good in wild weldability and is suitable for construction of conveying pipelines for petroleum and natural gas which are not dehydrogenized and contain a hydrogen sulfide medium.

Description

technical field [0001] The invention belongs to the technical field of smelting, and in particular relates to a steel plate for acid corrosion-resistant X70MS pipelines, and also relates to a manufacturing method of the above-mentioned steel plate. Background technique [0002] With the increasing demand for natural gas clean energy in my country, the construction of natural gas pipelines is developing towards high strength, high toughness, large diameter, and high transmission efficiency. When transporting hydrogen sulfide (H 2 S) In case of natural gas in sour medium, in order to prevent the acid gas from corrosive damage to the pipeline, the pipeline steel is required to have resistance to hydrogen induced cracking (Hydrogen Induced Crack, HIC for short) and H 2 S stress corrosion (Sulfide Stress Corrosion, SSCC for short) performance. [0003] Natural gas resources are abundant in western my country, but H 2 The content of S is high. In order to reduce the cost of pip...

AI Technical Summary

Problems solved by technology

The material of this invention contains Ni element, and the cost is relatively high; in addition, [C] and carbon equivalent in the material are relatively high, which is unfavorable to the low-temperature toughness, formability, weldability, and ductility of the material, and affects the comprehensive performance after pipe making; the invention The maximum thickness of the material is 12mm, and the low-temperature drop weight tearing area value of the steel is not listed. For example, the high-pressure and high-density medium is transported, and its wall thickness and low-temperature crack arrest toughness are obviously insufficient. Great destructive power, poor security

[0005] In addition, ZL200510023651.3 "X70 pipeline steel for acidic environment and its manufacturing method" discloses an X70 pipeline steel with HIC resistance for acidic environment; also discloses the above-mentioned X70 pipeline steel manufacturing method, using low carbon, high Manganese composition design idea, the carbon content is 0.02-0.05%, the converter sub-lance needs a large amount of oxygen blowing to achieve low carbon content, and the viscosity of the converter slag is very low, and the slag cannot be splashed to protect the furnace, which will greatly reduce the life of the converter

The material in the invention only has HIC hydrogen-induced cracking resistance, and has not been tested for SSCC stress corrosion resistance. The stress corrosion resistance represents the material’s ability to resist hydrogen sulfide corrosion under dynamic loading force, which can better simulate the actual situation of pipelines transporting natural gas under pressure. Missing anti-SSCC check item

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