Search

CN-122013183-A - Seamless steel tube for low temperature and processing technology thereof

CN122013183ACN 122013183 ACN122013183 ACN 122013183ACN-122013183-A

Abstract

The invention discloses a low-temperature seamless steel pipe and a processing technology thereof, and relates to the technical field of seamless steel pipes, wherein the processing technology comprises the following steps of sequentially carrying out converter smelting, secondary refining, vacuum degassing and continuous casting on raw materials according to a formula to obtain a pipe blank; heating, perforating, continuous rolling, removing the tube, reducing the diameter by tension and carrying out heat treatment on the tube blank to obtain a raw tube, sequentially carrying out surface pretreatment, electroplating and chemical vapor deposition on the raw tube to obtain a first steel tube, sequentially immersing the first steel tube in a 3-aminopropyl triethoxysilane solution and a dibutyl phosphate cerium suspension, and drying to obtain the low-temperature seamless steel tube.

Inventors

  • XU SHENG
  • DONG XIYUE
  • WANG HONGHAI
  • CHEN DONG
  • ZHU GUANGYA

Assignees

  • 德新钢管（中国）有限公司

Dates

Publication Date
20260512
Application Date
20260129

Claims (10)

  1. 1. S1, sequentially carrying out converter smelting, secondary refining, vacuum degassing and continuous casting on raw materials according to a formula to obtain a tube blank; s2, heating, perforating, continuous rolling, pipe removing, tension reducing and heat treatment are sequentially carried out on the pipe blank to obtain an original pipe; S3, sequentially carrying out surface pretreatment, electroplating and chemical vapor deposition on the original pipe to obtain a first steel pipe; and S4, immersing the first steel pipe into a 3-aminopropyl triethoxysilane solution and a dibutyl phosphate cerium suspension in sequence, and drying to obtain the low-temperature seamless steel pipe.
  2. 2. A process for machining a low-temperature seamless steel tube according to claim 1, wherein the chemical composition of the tube blank is C：0.15-0.16%,Si：0.36-0.40%,Mn：1.43-1.50%,Als：0.15-0.32%,Ti：0.15-0.21%,Nb：0.42-0.51%,N：0.0028-0.0032% in mass percent, and the balance is Fe and unavoidable impurities.
  3. 3. The process for manufacturing a seamless steel pipe for low temperature according to claim 1, wherein the heat treatment temperature is 890-910 ℃ and the time is 40-60min.
  4. 4. The process for processing the low-temperature seamless steel tube is characterized by comprising the specific steps of polishing the surface of an original tube by using No. 180, 320, 800, 1200 and 2500 sand paper in sequence, polishing by using a 3-4 mu m diamond polishing solution, ultrasonically cleaning by using acetone for 5-10min, and drying by using compressed air.
  5. 5. The process for manufacturing the seamless steel tube for low temperature use according to claim 1, wherein the specific electroplating step comprises the steps of electroplating a copper layer on the surface of the original tube and then electroplating a nickel layer on the copper layer sequentially by electroplating using a nickel sulfamate solution and a copper sulfate solution.
  6. 6. The process for manufacturing a seamless steel pipe for low temperature according to claim 5, wherein the concentration of the main salt in the nickel sulfamate solution is 200-450g/L, the concentration of boric acid is 30-50g/L, the temperature is 55-60 ℃, the pH is 3.9-4.1, the concentration of the main salt in the copper sulfate solution is 50-100g/L, the concentration of sulfuric acid is 50-100g/L, the temperature is 20-25 ℃, the pH is 3.9-4.1, the electroplating parameters include 8-10A of current, the thickness of a copper layer is 13-15 μm, and the thickness of a nickel layer is 12-14 μm.
  7. 7. The process for manufacturing the seamless steel tube for low temperature according to claim 1, wherein the chemical vapor deposition comprises the specific steps of placing the original tube in a tube furnace with a vacuum degree of 5mtorr, introducing mixed gas of argon and hydrogen at a flow rate of between 250 and 280sccm at a pressure of between 1.8 and 2.2torr, preheating the tube to a temperature of between 1060 and 1061 ℃ for 40 to 45 minutes, introducing hexane at a flow rate of between 1 and 1.2.2sccm at a temperature of between 1060 and 1061 ℃ for 55 to 60 minutes, and cooling the tube to room temperature at a pressure of between 1.8 and 2.2torr and a flow rate of mixed gas of argon and hydrogen at a flow rate of between 250 and 280 sccm.
  8. 8. The process for processing the low-temperature seamless steel tube according to claim 1, wherein in the step S4, the preparation method of the low-temperature seamless steel tube comprises the following steps of (1) adding 3-aminopropyl triethoxysilane into N, N-dimethyl formamide, and uniformly stirring to obtain a 3-aminopropyl triethoxysilane solution; Adding dibutyl cerium phosphate into deionized water, performing ultrasonic dispersion, adding 3-aminopropyl triethoxysilane, and uniformly stirring to obtain dibutyl cerium phosphate suspension; And (3) immersing the first steel pipe into a 3-aminopropyl triethoxysilane solution, heating to 100-105 ℃ for reaction for 6-6.5h, adding a dibutyl cerium phosphate suspension, cooling to 50-55 ℃ for reaction for 12-24h, washing with an aqueous ethanol mixed solution with the volume ratio of 1:1, and drying to obtain the low-temperature seamless steel pipe.
  9. 9. The process for processing the low-temperature seamless steel tube according to claim 7, wherein the concentration of the 3-aminopropyl triethoxysilane solution is 18.8-20g/L, and the mass ratio of the 3-aminopropyl triethoxysilane to the dibutyl cerium phosphate is 1.88 (2-4) in the preparation process of the dibutyl cerium phosphate suspension.
  10. 10. A seamless steel pipe for low temperature produced by the process for producing a seamless steel pipe for low temperature according to any one of claims 1 to 9.

Description

Seamless steel tube for low temperature and processing technology thereof Technical Field The invention relates to the technical field of seamless steel pipes, in particular to a low-temperature seamless steel pipe and a processing technology thereof. Background In the field of seamless steel pipe technology, seamless steel pipes used in low temperature environments face a number of challenges. With the continuous development of industry, such as the fields of low-temperature liquid storage and transportation, low-temperature chemical industry and the like, the performance requirements on the seamless steel pipe for low temperature are increasingly severe. In a low-temperature environment, the toughness of the traditional seamless steel pipe is obviously reduced, brittle fracture is easy to occur, and the safe operation of related equipment is seriously influenced. In terms of chemical composition, conventional seamless steel pipe composition designs fail to adequately account for performance optimization under low temperature conditions, e.g., certain alloying elements can negatively impact the toughness of the steel pipe at low temperatures, resulting in poor performance when subjected to pressure and impact. In the processing technology, the prior technology is difficult to form an ideal protection structure on the surface of the steel pipe. The common surface treatment mode can not effectively improve the corrosion resistance of the steel pipe, so that the steel pipe is extremely easily corroded and damaged in a low-temperature corrosive environment, the service life is shortened, and the maintenance cost and the safety risk are increased. Therefore, it is urgent to develop a seamless steel pipe having excellent low temperature properties and corrosion resistance and a process for manufacturing the same. Disclosure of Invention The invention aims to provide a seamless steel tube for low temperature and a processing technology thereof, which are used for solving the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: S1, sequentially carrying out converter smelting, secondary refining, vacuum degassing and continuous casting on raw materials according to a formula to obtain a tube blank; s2, heating, perforating, continuous rolling, pipe removing, tension reducing and heat treatment are sequentially carried out on the pipe blank to obtain an original pipe; S3, sequentially carrying out surface pretreatment, electroplating and chemical vapor deposition on the original pipe to obtain a first steel pipe; and S4, immersing the first steel pipe into a 3-aminopropyl triethoxysilane solution and a dibutyl phosphate cerium suspension in sequence, and drying to obtain the low-temperature seamless steel pipe. Further, the chemical components of the pipe blank are, by mass, 0.15-0.16% of C, 0.36-0.40% of Si, 1.43-1.50% of Mn, 0.15-0.32% of Als (acid-soluble aluminum), 0.15-0.21% of Ti, 0.42-0.51% of Nb, 0.0028-0.0032% of N, and the balance of Fe and unavoidable impurities. Further, the heat treatment temperature is 890-910 ℃ and the time is 40-60min. Further, the specific surface pretreatment step comprises the steps of polishing the surface of the original pipe by using No. 180, no. 320, no. 800, no. 1200 and No. 2500 sand paper in sequence, polishing by using a 3-4 mu m diamond polishing solution, ultrasonically cleaning by using acetone for 5-10min, and drying by using compressed air. Further, the electroplating method specifically comprises the steps of electroplating a copper layer on the surface of the original pipe sequentially by using a nickel sulfamate solution and a copper sulfate solution, and then electroplating a nickel layer on the copper layer. Further, the concentration of main salt in the nickel sulfamate solution is 200-450g/L, the concentration of boric acid is 30-50g/L, the temperature is 55-60 ℃, the pH is 3.9-4.1, the concentration of main salt in the copper sulfate solution is 50-100g/L, the concentration of sulfuric acid is 50-100g/L, the temperature is 20-25 ℃, the pH is 3.9-4.1, the electroplating parameters comprise 8-10A of current, 13-15 mu m of copper layer thickness and 12-14 mu m of nickel layer thickness. Further, the chemical vapor deposition comprises the specific steps of placing the original tube in a tube furnace with the vacuum degree of 5mtorr, introducing argon and hydrogen mixed gas at the flow rate of 250-280sccm under the pressure of 1.8-2.2torr, preheating to 1060-1061 ℃ for 40-45min, introducing hexane at the flow rate of 1-1.2.2sccm, maintaining at 1060-1061 ℃ for 55-60min, and cooling to room temperature under the flow of the argon and hydrogen mixed gas at the flow rate of 250-280sccm under the pressure of 1.8-2.2 torr. Further, in the step S4, the preparation method of the seamless steel tube for low temperature comprises the following steps that (1) 3-aminopropyl triethoxysilane is add