CN-121976132-A - High-temperature-resistant corrosion-resistant seamless steel pipe for petrochemical industry and preparation method thereof

CN121976132ACN 121976132 ACN121976132 ACN 121976132ACN-121976132-A

Abstract

The invention discloses a high-temperature-resistant corrosion-resistant seamless steel tube for petrochemical industry and a preparation method thereof, wherein the high-temperature-resistant corrosion-resistant seamless steel tube comprises the following components in percentage by weight: c:0.10% -0.14%, si:0.30 to 0.90 percent of Mn:0.35 to 0.55 percent of Cr:6.5 to 7.5 percent of Mo:0.70% -0.78%, W:0.10% -0.15%, P is less than or equal to 0.018%, S is less than or equal to 0.008%, and the balance is iron and unavoidable impurities. The seamless steel pipe has excellent strength and toughness, excellent metallographic structure phase composition and optimized inclusion morphology; meanwhile, the steel pipe has high normal temperature tensile property and good high temperature tensile and creep properties, has excellent corrosion resistance, prolongs the service life and improves the safety of the steel pipe, and can be widely applied to the use of petrochemical steel pipes.

Inventors

ZHAO BO
WANG SHANBAO
XIE DEGANG
YUAN QIN
GAO HANG
WANG XIXIANG

Assignees

鞍钢股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260209

Claims (10)

1. The high-temperature-resistant corrosion-resistant seamless steel pipe for petrochemical industry is characterized by comprising the following components in percentage by weight: C：0.10％～0.14％、Si：0.30％～0.90％、Mn：0.35％～0.55％、Cr：6.5％～7.5％、Mo：0.70％～0.78％、W：0.10％~0.15%、P≤0.018％、S≤0.008％, And the balance iron and unavoidable impurities.
2. The petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 1, wherein the outer diameter of the seamless steel pipe is 60-180 mm, and the wall thickness is 5-25 mm; when the wall thickness is less than or equal to 5mm and less than 10mm, the normal-temperature impact energy of the longitudinal 1/2 size is more than or equal to 120J; when the wall thickness is less than or equal to 10mm when the diameter is less than or equal to 25mm, the longitudinal full-size normal-temperature impact energy is more than or equal to 200J; the normal temperature elongation rate of the seamless steel pipe is more than or equal to 24%, the normal temperature yield strength is more than or equal to 450MPa, and the normal temperature tensile strength is more than or equal to 650MPa; The yield strength of the seamless steel pipe is more than or equal to 350MPa at 525 ℃ and the tensile strength of the seamless steel pipe is more than or equal to 425MPa at 525 ℃; The yield strength of the seamless steel pipe is more than or equal to 120MPa at 700 ℃ and the tensile strength of the seamless steel pipe is more than or equal to 140MPa at 700 ℃.
3. The petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 1, wherein the metallographic structure of the seamless steel pipe is tempered sorbite, the phase composition of the seamless steel pipe is 91-93% of equiaxed ferrite and 7-9% of spherical carbide by volume percentage, and the spherical carbide comprises alloy cementite, chromium carbide and molybdenum carbide.
4. The petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 1, wherein the inclusion grade of the seamless steel pipe is less than or equal to 1.0 grade, the sulfide inclusion grade is less than or equal to 0.5 grade, the sulfide inclusions are spherically distributed, and the ratio of the diameter of a central loose area of a round billet of the steel pipe to the diameter of the round billet is less than 0.1.
5. The petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 1, wherein the corrosion rate of the seamless steel pipe is less than 0.4 g/(m 2 . Multidot.h) by adopting a NaCl solution with mass fraction of 5% and performing a salt spray test for 72h at a test temperature of 33-37 ℃.
6. A method for producing a petrochemical, high-temperature-resistant, corrosion-resistant seamless steel pipe according to any one of claims 1 to 5, comprising smelting, continuous casting, heating, hot rolling and heat treatment; In the hot rolling, a heated casting blank is rolled into a hot rolled steel pipe by adopting perforation, PQF continuous rolling and a stretch reducing process in sequence, wherein the perforation temperature is controlled to be 1235-1250 ℃, the biting speed is controlled to be 210-230 r/min, the rolling speed is controlled to be 450-470 r/min, the advancing angle of a perforating machine is 8-9.5 degrees, the PQF continuous rolling outlet speed is controlled to be 2700-280mm/s, and the temperature of the outlet steel pipe after the stretch reducing is controlled to be 910-950 ℃; The heat treatment is controlled to be carried out within 20 hours after hot rolling, the steel pipe is subjected to normalizing treatment and tempering treatment in sequence, the normalizing treatment temperature is 930-950 ℃, the heat preservation time is 60-70 min, tempering treatment is carried out after air cooling to room temperature, the temperature is increased to 500 ℃ at the temperature increasing speed of 60-70 ℃ per hour, and the heat preservation time is 150-180 min after the temperature is increased to 750-800 ℃ at the temperature increasing speed of 90-100 ℃ per hour.
7. The method for preparing the petrochemical high-temperature-resistant corrosion-resistant seamless steel tube according to claim 6, wherein in the smelting, electric furnace smelting, external refining and vacuum degassing methods are adopted, the tapping temperature of an electric furnace is 1705-1715 ℃, and the entering temperature of an LF furnace is >1660 ℃ and stirring is adopted in the whole process.
8. The method for producing a petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 6, wherein in the continuous casting, the superheat degree is controlled to be 40-45 ℃, the drawing speed is controlled to be 0.3-0.4 m/min, the drawing speed is controlled to be constant in the continuous casting, a crystallizer electromagnetic stirring and a terminal electromagnetic stirring are used, the current of the electromagnetic stirring of the crystallizer is 430-460A, the current of the terminal electromagnetic stirring is 500-550A, the soft reduction is set to be 5 mm-8 mm, and then the continuous casting is annealed to obtain a casting blank with the annealed hardness HBW of 200-240.
9. The method for preparing the petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 6, wherein in the heating, the casting blank enters a heating furnace with the furnace temperature less than or equal to 450 ℃, is heated to 850 ℃ and then is kept for 100-110 min, the heating time is controlled to be not less than 40min, and is heated to 1260-1275 ℃ and then is kept for 110-120 min.
10. The method for producing a petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe according to claim 6, wherein the hot rolled steel pipe has a hot rolled structure of lath martensite and the heat-treated metallographic structure is tempered sorbite.

Description

High-temperature-resistant corrosion-resistant seamless steel pipe for petrochemical industry and preparation method thereof Technical Field The invention relates to the technical field of seamless pipe manufacture, in particular to the technical field of steel pipes for petrochemical industry, and more particularly relates to a high-temperature-resistant corrosion-resistant seamless steel pipe for petrochemical industry and a preparation method thereof. Background A large number of equipment and pipelines in petrochemical industry and oil refining industry run under high temperature and high pressure and hydrogen-critical conditions for a long time, such as hydrocracking, hydrofining, hydrogen production, reforming, catalysis, ethylene, coking and other devices. The metal can be degraded in pipe body material and its performance can be reduced due to long-term running at high temperature, and hydrogen sulfide can produce serious corrosion (hydrogen corrosion, hydrogen embrittlement, wall thickness reduction due to hydrogen sulfide corrosion, etc.) to steel material at high temperature. Therefore, at present, a large amount of Cr-Mo steel grades are used in domestic petrochemical and oil refining devices at the temperature of 300-500 ℃. The steel has good high-temperature durable strength, creep resistance and durable plasticity, and meanwhile, the steel is widely used in power stations and petrochemical industry due to excellent oxidation resistance and corrosion resistance. The patent application with publication number CN119287260A discloses a CO 2 corrosion resistant steel, a preparation method thereof and a steel product, and the patent is added with Cr, mo, al and other alloys, and has corrosion resistance but not high temperature resistance. The patent application with publication number CN119332155A discloses a manufacturing method of a high-strength carbon dioxide and hydrogen sulfide corrosion resistant rare earth microalloying drill rod, and the patent is added with higher Cr, mo and other alloys, has high price, is mainly applied to the drill rod in a corrosion resistant environment, and does not reflect the use effect of the drill rod in a high-temperature environment. The patent application with publication number CN104959784A discloses a preparation method of a P91 seamless steel pipe, the production process of the patent is complex, and is only a hot rolling production process, the subsequent heat treatment production process is not described, and the performance condition of the P91 product produced by adopting the process can not be judged. The patent application with publication number CN120425198A discloses a standby Ni-Cr-Mo corrosion resistant alloy seamless pipe for a petroleum tool and a manufacturing method, the patent adds higher-content Cr, mo, ni and other alloys, the production process is a smelting-hot extrusion-cold rolling-pickling process, the process is complex, and a product with a larger caliber cannot be produced. Disclosure of Invention The invention aims to overcome the defects in the prior art, and provides a high-temperature-resistant corrosion-resistant seamless steel pipe for petrochemical industry and a preparation method thereof, wherein a chemical component system is optimized and is matched with smelting, continuous casting, heating, hot rolling and heat treatment processes to prepare the seamless steel pipe with the outer diameter of 60-180 mm and the wall thickness of 5-25 mm, the seamless steel pipe has excellent toughness, good metallographic structure phase composition and optimized inclusion morphology, and meanwhile, the seamless steel pipe has higher normal-temperature tensile property and good high-temperature tensile and creep properties, has excellent corrosion resistance, prolongs the service life and safety of the steel pipe, and can be widely applied to the steel pipe for petrochemical industry. In order to achieve the above purpose, the technical scheme of the invention is as follows: A high-temperature-resistant corrosion-resistant seamless steel pipe for petrochemical industry comprises the following components ：C：0.10％～0.14％、Si：0.30％～0.90％、Mn：0.35％～0.55％、Cr：6.5％～7.5％、Mo：0.70％～0.78％、W：0.10％~0.15%、P≤0.018％、S≤0.008％, in percentage by weight and the balance of iron and unavoidable impurities. The invention also discloses a preparation method of the petrochemical high-temperature-resistant corrosion-resistant seamless steel pipe, which comprises smelting, continuous casting, heating, hot rolling and heat treatment; In the hot rolling, a heated casting blank is rolled into a hot rolled steel pipe by adopting perforation, PQF continuous rolling and a stretch reducing process in sequence, wherein the perforation temperature is controlled to be 1235-1250 ℃, the biting speed is controlled to be 210-230 r/min, the rolling speed is controlled to be 450-470 r/min, the advancing angle of a perforating machine is 8-9.5 degrees, the PQF continuous rolling out