CN-122013040-A - X80MS acid-resistant pipeline steel hot rolled steel strip and manufacturing method thereof

Abstract

The application discloses an X80MS acid-resistant pipeline steel hot rolled steel strip and a manufacturing method thereof, which relate to the technical field of pipeline steel manufacturing, and the chemical components comprise ：C：0.03～0.06%;Si：0.10～0.30%;Mn：0.80～1.20%;P：≤0.012%;S：≤0.0015%;Al：0.02～0.05%;Nb：0.060～0.080%;V：0.010～0.060%;Ti：0.005～0.020%;Cr：0.10～0.30%;Ni：0.10～0.30%;Cu：0.10～0.30%;Mo：0.10～0.30%, mass percent of Fe and unavoidable impurity elements, wherein Ceq is controlled to be less than or equal to 0.43%, and Pcm is controlled to be less than or equal to 0.20%. Breaks through the highest-level limit of API standard acid-resistant pipeline steel, and realizes the optimization of high strength and HIC and SSC double corrosion resistance. The refining process is combined with the continuous casting electromagnetic stirring and soft reduction technology, so that the high-purity casting blank with the Mannesmann center segregation rating less than or equal to 2 levels is obtained. By matching with the accurate rolling and cooling control process, the product forms a uniform fine-grain low-carbon bainite structure, and the problems of uneven structure and insufficient corrosion resistance of thick pipeline steel are effectively solved.

Inventors

• BIAN YUXIU
• WANG YUTIAN
• ZHAO YANFENG
• MA YOUGUANG
• TAN GUOHUA

Assignees

• 山西太钢不锈钢股份有限公司

Dates

Publication Date

20260512

Application Date

20260204

Claims (5)

1. 1. A hot rolled steel strip of X80MS acid-resistant pipeline steel is characterized in that the chemical components are ：C：0.03～0.06%;Si：0.10～0.30%;Mn：0.80～1.20%;P：≤0.012%;S：≤0.0015%;Al：0.02～0.05%;Nb：0.060～0.080%;V：0.010～0.060%;Ti：0.005～0.020%;Cr：0.10～0.30%;Ni：0.10～0.30%;Cu：0.10～0.30%;Mo：0.10～0.30%, percent by mass, the balance is Fe and unavoidable impurity elements, ceq is controlled to be less than or equal to 0.43 percent, and Pcm is controlled to be less than or equal to 0.20 percent.
2. 2. The hot rolled steel strip for an X80MS acid-resistant pipeline steel as claimed in claim 1, wherein the Ca content in the chemical composition is controlled to be 0.006% or less.
3. 3. A method of manufacturing an X80MS acid resistant pipeline steel hot rolled strip as claimed in claim 1 or claim 2 comprising the steps of, in order: the method comprises the steps of S1, in the steelmaking stage, molten iron meets the pretreatment end point condition that S is less than or equal to 0.005% and slag thickness is less than or equal to 30mm in the converter production process, the molten iron temperature is more than or equal to 1250 ℃, aluminum pellets are added for deoxidization treatment when the converter is tapped, 500-800kg of lime and 100-300kg of fluorite are added in the LF process, the total treatment time of the LF furnace is more than or equal to 45min, LF argon blowing is carried out to avoid the exposure of molten steel, and the vacuum degree is controlled to be less than or equal to 4mbar and the circulation time is not less than 15 min after RH vacuum treatment; Step S2, adopting protection casting, and adopting a four-section roller type electromagnetic stirring and light pressing process, wherein the temperature of a tundish is controlled to be 1540-1550 ℃, and the pulling speed is controlled to be 0.80-1.25 m/min; and step S3, in a hot rolling stage, the soaking temperature of slab heating is 1160-1220 ℃, the residence time is 180-220 min, rolling is divided into two stages of rough rolling and finish rolling, the finishing temperature of rough rolling is less than or equal to 970 ℃, the finishing temperature of finish rolling is 800-850 ℃, laminar cooling is adopted after rolling, the cooling speed is more than or equal to 20 ℃ per second, and the coiling target temperature is controlled at 300-500 ℃.
4. 4. A method for producing an X80MS acid-proof pipeline steel hot rolled steel strip according to claim 3, wherein in step S1, temperature-adjusting deep desulfurization and composition fine adjustment are performed during LF.
5. 5. A method for producing an X80MS acid-proof pipe steel hot rolled steel strip according to claim 3, wherein in step S2, at least the tail sampling of the first block of the casting blank per casting pass is subjected to a low-power inspection, rated according to the mannesmann center segregation criterion, and the acceptance criterion is no more than 2.

Description

X80MS acid-resistant pipeline steel hot rolled steel strip and manufacturing method thereof Technical Field The application belongs to the technical field of pipeline steel manufacturing, and particularly relates to an X80MS acid-resistant pipeline steel hot rolled steel strip and a manufacturing method thereof. Background Pipeline transportation is used as a core mode for long-distance transportation of petroleum and natural gas, and is the first choice for energy transportation by virtue of economy, safety and high efficiency. However, as global oil and gas production gradually expands to complex environments such as deep sea and high sulfur-containing formations, the content of hydrogen sulfide (H 2 S) in the conveying medium is significantly increased, which puts very severe demands on the corrosion resistance of pipeline steel. Hydrogen Induced Cracking (HIC) and sulfide stress corrosion cracking (SSC) induced by hydrogen sulfide not only shorten the service life of steel pipes, but also are more likely to cause oil and gas leakage, thereby causing safety accidents and causing great economic loss. Therefore, the development and upgrading of acid-resistant pipeline steel is an urgent need of the industry. Currently, the highest grade of acid-resistant pipeline steel specified by the international API standard is X70MS, the highest grade of commercial batch application is only X65MS, the common grade is mainly concentrated on X52MS and X60MS, and the mature preparation technology of the high-grade X80MS acid-resistant pipeline steel is still in a blank state. On the one hand, natural contradiction exists between high strength and hydrogen sulfide corrosion resistance, the increase of steel grade and thickness can aggravate component segregation and uneven structure so as to reduce corrosion resistance, on the other hand, the existing technical scheme has obvious defects, for example, the patent with publication number CN107974614A discloses a production method of X80 grade pipeline steel for resisting hydrogen induced cracking corrosion, the C, mn content is too low, and more alloy elements are required to be added in order to ensure the performance of products with the same thickness specification, so that the production cost is increased. Also, the patent relates only to HIC resistance, and no SSC resistance is mentioned. In addition, the patent with publication number CN107604249A discloses an economical anti-HIC and anti-SSCC X80MS pipeline steel, but the product is a hot-rolled middle plate, cannot meet the industrial application requirements of a steel belt, and has over-high Mn content, so that center segregation is easy to generate, and the hydrogen sulfide corrosion resistance is unstable. In addition, the requirements of the acid-resistant pipeline steel on the purity of molten steel, the uniformity of casting blanks and the welding performance are far higher than those of common pipeline steel, namely, the impurity elements such as P, S in the steel are easy to cause segregation, the corrosion resistance is deteriorated, the impurities such as MnS are the main inducement of HIC, the stress concentration is caused by uneven structure, the SSC resistance is reduced, and meanwhile, the component design of the high-grade pipeline steel needs to be compatible with the strength and the welding toughness, so that the welding performance is prevented from being reduced due to excessive addition of alloy elements. Therefore, development of a manufacturing technology of an X80MS grade acid-resistant hot rolled steel strip is needed to solve the technical problems of high strength and corrosion resistance synergy, ingredient and process adaptation and the like. Disclosure of Invention In order to solve part or all of the technical problems in the prior art, the application provides an X80MS acid-resistant pipeline steel hot rolled steel strip and a manufacturing method thereof. The application provides an X80MS acid-resistant pipeline steel hot rolled steel strip, which comprises the chemical components of ：C：0.03～0.06%;Si：0.10～0.30%;Mn：0.80～1.20%;P：≤0.012%;S：≤0.0015%;Al：0.02～0.05%;Nb：0.060～0.080%;V：0.010～0.060%;Ti：0.005～0.020%;Cr：0.10～0.30%;Ni：0.10～0.30%;Cu：0.10～0.30%;Mo：0.10～0.30%, percent by mass, and the balance of Fe and unavoidable impurity elements, wherein Ceq is controlled to be less than or equal to 0.43 percent, and Pcm is controlled to be less than or equal to 0.20 percent. Preferably, the Ca content in the chemical component is controlled below 0.006%. The application provides a manufacturing method of an X80MS acid-resistant pipeline steel hot rolled steel strip, which is characterized by comprising the following steps in sequence: the method comprises the steps of S1, in the steelmaking stage, molten iron meets the pretreatment end point condition that S is less than or equal to 0.005% and slag thickness is less than or equal to 30mm in the converter production process, the molten iron tem