Sulfuric-acid-corrosion-resistant low-alloy steel, steel pipe, steel plate and manufacturing methods of steel pipe and steel plate

Abstract

The invention discloses sulfuric-acid-corrosion-resistant low-alloy steel. The microstructure of the low-alloy steel is a ferrite and a pearlite. The sulfuric-acid-corrosion-resistant low-alloy steelcomprises the chemical elements of, by mass, greater than 0 and less than or equal to 0.15% of C, 0.1-0.4% of Si, 0.28-0.85% of Mn, 0.004-0.02% of S, 0.25-0.9% of Cr, 0.02-0.35% of Cu, 0.01-0.04% of Sb, 0.01-0.03% of Sn and the balance Fe and other inevitable impurities, wherein the value of (Sb+Sn) / S is 1 to 15. In addition, the invention further discloses a steel plate and a steel pipe made of the sulfuric-acid-corrosion-resistant low-alloy steel and manufacturing methods of the steel plate and the steel pipe. According to the sulfuric-acid-corrosion-resistant low-alloy steel, the sulfuric acid resistance is high, meanwhile relatively high hardness and strength are achieved, and the abrasive wear resistance is high.

Description

technical field [0001] The invention relates to a steel, a steel product and a manufacturing method thereof, in particular to a low-alloy steel, a steel product and a manufacturing method thereof. Background technique [0002] Petrochemical plants, coal power plants, iron and steel smelting plants, etc. produce a large amount of flue gas all year round, which contains a large amount of SO 3 , SO 2 and other acid gases, SO 2 Further generation of SO under catalysis 3 , when the flue gas temperature is lower than the dew point of sulfuric acid, condensation will form sulfuric acid dew point corrosion. In order to save energy, reduce emission and reduce pollution, low-temperature desulfurization process is generally used, and sulfuric acid dew point corrosion is bound to occur. [0003] The single resistance to sulfuric acid dew point corrosion generally relies on Cu or Cu-Sb system to achieve its corrosion resistance. For example, the single sulfuric acid dew point corros...

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Problems solved by technology

The composition range of both depends on the separate sulfuric acid or hydrochloric acid corrosion test, and does not involve mixed acid corrosion, especially the lack of corrosion resistance evaluation in flue gas simulation environment such as dead green liquor, because mixed acid corrosion cannot be used for corrosion resistance of single component acid Simple physical superposition of results

In the same way, only a low concentration of 1% is used to evaluate its good hydrochloric acid corrosion resistance, and its corrosion resistance in high concentration hydrochloric acid is unknown

[0005] In addition, the flue gas contains a large number of particles, and the wind speed is high, resulting in serious abrasive wear of the material. For example, a device made of traditional 09CrCuSb steel by a company in Yantai failed due to wear and perforation in about 3 to 4 months

And the above materials basically need normalizing or normalizing + tempering heat treatment, the strength is low, based on the proportional relationship between strength and hardness, its wear resistance is also low

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