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CN-121976119-A - Corrosion-resistant enhanced duplex stainless steel and heat treatment process thereof

CN121976119ACN 121976119 ACN121976119 ACN 121976119ACN-121976119-A

Abstract

The invention is suitable for the technical field of metal materials, and provides corrosion-resistant enhanced duplex stainless steel and a heat treatment process thereof, wherein the corrosion-resistant enhanced duplex stainless steel comprises, by weight, 90-95 parts of a duplex stainless steel substrate, 3-5 parts of nano titanium nitride, 1-2 parts of modified graphene, 0.5-1 part of niobium powder, 0.3-0.8 part of vanadium powder and 0.2-0.5 part of yttrium powder. According to the invention, the components of the duplex stainless steel matrix are optimized, the treated nano titanium nitride and graphene are introduced, and the alloy elements such as niobium, vanadium and yttrium are cooperated, so that the corrosion resistance, mechanical property and tissue stability of the duplex stainless steel are obviously improved by matching with specific solid solution and aging heat treatment processes, and the problems that the conventional duplex stainless steel is easy to separate out harmful phases at high temperature or in a corrosive environment and the performance is reduced are solved.

Inventors

  • WANG RUI
  • CHANG TIANYI
  • YAN ZHIJIE
  • YU ZHIQIANG
  • KANG YAN
  • SHI ZHIYUE

Assignees

  • 中北大学

Dates

Publication Date
20260505
Application Date
20260126

Claims (10)

  1. 1. The corrosion-resistant enhanced duplex stainless steel is characterized by comprising the following raw materials in parts by weight: 90-95 parts of duplex stainless steel matrix, 3-5 parts of nano titanium nitride, 1-2 parts of modified graphene, 0.5-1 part of niobium powder, 0.3-0.8 part of vanadium powder and 0.2-0.5 part of yttrium powder; The nano titanium nitride is treated as follows: S101, placing nano titanium nitride in a plasma treatment instrument, introducing argon, controlling the flow of the argon to be 15-20mL/min, treating for 15-20min, keeping the pressure of a cavity to be 0.05-0.1MPa in the treatment process, and cooling to room temperature to obtain pretreated titanium nitride; S102, adding pretreated titanium nitride into hydrochloric acid solution, wherein the liquid-solid ratio of the hydrochloric acid solution to the pretreated titanium nitride is 10:1, performing ultrasonic dispersion for 30-40min at 25-30 ℃, then repeatedly washing with deionized water until the pH value of a washing solution is 6.8-7.2, and performing vacuum drying for 2-3h at 80-90 ℃ to obtain the purified nano titanium nitride.
  2. 2. The corrosion-resistant reinforced duplex stainless steel according to claim 1, comprising the following raw materials in parts by weight: 92.5 parts of duplex stainless steel matrix, 4 parts of nano titanium nitride, 1.5 parts of modified graphene, 0.7 part of niobium powder, 0.5 part of vanadium powder and 0.3 part of yttrium powder.
  3. 3. The corrosion-resistant reinforced duplex stainless steel according to claim 1, wherein the modified graphene is modified by the following method: S301, dispersing graphene oxide in deionized water, and performing ultrasonic dispersion for 25-30min to prepare graphene oxide dispersion liquid with the concentration of 0.5-1 mg/mL; S302, adding nano aluminum powder, which is 30-50% of the mass of graphene oxide, into the graphene oxide dispersion liquid, stirring for 20-40min under the condition of 200-250r/min, centrifuging at the rotating speed of 8000-10000r/min after stirring is finished for 15-20min, collecting a solid phase, and freeze-drying at-40 to-30 ℃ for 12-15h to obtain the modified graphene.
  4. 4. The corrosion-resistant reinforced duplex stainless steel according to claim 3, wherein the particle size of the nano aluminum powder is 20-50nm, and the vacuum degree is less than or equal to 10Pa in the freeze drying process.
  5. 5. The corrosion-resistant reinforced duplex stainless steel according to claim 1, wherein the chemical composition of the duplex stainless steel matrix, in mass percent, comprises ：C≤0.03%、Si0.6-0.8%、Mn5.0-5.5%、P≤0.025%、S≤0.003%、Cr21.0-22.0%、Ni1.3-1.5%、Mo0.15-0.2%、Cu0.1-0.15%、N0.2-0.25%, the balance of Fe and unavoidable impurities.
  6. 6. The corrosion resistant reinforced duplex stainless steel according to claim 1, wherein the nano titanium nitride has a particle size of 50-100nm.
  7. 7. A heat treatment process of the corrosion-resistant reinforced duplex stainless steel according to any one of claims 1 to 6, comprising the steps of: s701, weighing all raw materials according to parts by weight, putting the raw materials into a high-speed mixer, and mixing the raw materials for 15-20min at 25-30 ℃ and 800-1000r/min to obtain mixed raw materials; Adding the mixed raw materials into a vacuum induction furnace, vacuumizing until the vacuum degree of the cavity is less than or equal to 5 multiplied by 10 -3 Pa, then heating to 1500-1550 ℃, preserving heat for 30-40min, stirring once every 10min in the heat preservation process, and stirring for 5min each time, wherein the stirring speed is 50-80r/min; Then injecting the molten metal into a water-cooled copper mold preheated to 200-250 ℃, controlling the cooling rate of a casting blank to be 10-15 ℃ per second, cooling to room temperature, and demolding to obtain the casting blank; S702, placing a casting blank into a box-type resistance furnace, heating to 600-650 ℃ at a rate of 5-8 ℃ per minute, and preserving heat for 20-30 minutes to perform preheating treatment; After preheating, heating to 1080-1120 ℃ at the speed of 10-15 ℃ per min, and preserving heat for 40-60min for solution treatment; Immediately placing the casting blank into deionized water at 20-25 ℃ for water quenching and cooling after the solution treatment is finished, and cooling to room temperature to obtain a blank after the solution treatment; S703, putting the blank subjected to solution treatment into a box-type resistance furnace again, heating to 650-700 ℃ at a rate of 3-5 ℃ per minute, and preserving heat for 90-120 minutes; then heating to 850-900 ℃ at the speed of 5-8 ℃ per min, and preserving heat for 30-45min for sectional aging treatment; And after the aging treatment is finished, taking out the blank, and naturally cooling the blank to room temperature in an environment with the temperature of 20-25 ℃ and the relative humidity of less than or equal to 60% to obtain the corrosion-resistant reinforced duplex stainless steel.
  8. 8. The heat treatment process according to claim 7, wherein in step S701, the flow rate of cooling water of the water-cooled copper mold is 1.5 to 2.0m/S; the dimensional deviation of the casting blank is controlled to be +/-0.5 mm.
  9. 9. The heat treatment process according to claim 7, wherein in step S702, deionized water is continuously stirred during the water quenching and cooling process, and the stirring rate is 100-150r/min.
  10. 10. The heat treatment process according to claim 7, wherein in step S703, the air cooling process is performed with the aid of a blower, and the blower speed is 3-5m/S.

Description

Corrosion-resistant enhanced duplex stainless steel and heat treatment process thereof Technical Field The invention relates to the technical field of metal materials, in particular to corrosion-resistant enhanced duplex stainless steel and a heat treatment process thereof. Background The duplex stainless steel has both excellent toughness of austenitic stainless steel and high strength and corrosion resistance of ferritic stainless steel, and is widely applied in the fields of chemical industry, petroleum, ocean engineering and the like. However, in the high-temperature environment or in a severe corrosion medium, the conventional duplex stainless steel is easy to separate out sigma phase, cr 2 N and other harmful phases, so that the toughness and corrosion resistance of the material are greatly reduced, and the application of the duplex stainless steel under a more severe working condition is limited. In the prior art, the structure performance of the duplex stainless steel can be improved to a certain extent by optimizing a solid solution-aging process, but the problem of precipitation of a harmful phase is difficult to fundamentally solve by a simple heat treatment process, and the performance improvement effect is limited due to the problems of uneven element dispersion, poor compatibility with a matrix and the like in a modification mode of adding alloy elements. Therefore, in view of the above situation, there is an urgent need to provide a corrosion-resistant reinforced duplex stainless steel and a heat treatment process thereof, so as to overcome the shortcomings in the current practical application. Disclosure of Invention The invention aims to provide corrosion-resistant enhanced duplex stainless steel and a heat treatment process thereof, which effectively solve the problems in the background technology. The invention is realized in such a way that the corrosion-resistant enhanced duplex stainless steel comprises the following raw materials in parts by weight: 90-95 parts of duplex stainless steel matrix, 3-5 parts of nano titanium nitride, 1-2 parts of modified graphene, 0.5-1 part of niobium powder, 0.3-0.8 part of vanadium powder and 0.2-0.5 part of yttrium powder; The nano titanium nitride is treated as follows: S101, placing nano titanium nitride in a plasma treatment instrument, introducing argon, controlling the flow of the argon to be 15-20mL/min, treating for 15-20min, keeping the pressure of a cavity to be 0.05-0.1MPa in the treatment process, and cooling to room temperature to obtain pretreated titanium nitride; S102, adding pretreated titanium nitride into hydrochloric acid solution, wherein the liquid-solid ratio of the hydrochloric acid solution to the pretreated titanium nitride is 10:1, performing ultrasonic dispersion for 30-40min at 25-30 ℃, then repeatedly washing with deionized water until the pH value of a washing solution is 6.8-7.2, and performing vacuum drying for 2-3h at 80-90 ℃ to obtain the purified nano titanium nitride. The invention further adopts the scheme that the feed comprises the following raw materials in parts by weight: 92.5 parts of duplex stainless steel matrix, 4 parts of nano titanium nitride, 1.5 parts of modified graphene, 0.7 part of niobium powder, 0.5 part of vanadium powder and 0.3 part of yttrium powder. The method for modifying the modified graphene comprises the following steps of: S301, dispersing graphene oxide in deionized water, and performing ultrasonic dispersion for 25-30min to prepare graphene oxide dispersion liquid with the concentration of 0.5-1 mg/mL; S302, adding nano aluminum powder, which is 30-50% of the mass of graphene oxide, into the graphene oxide dispersion liquid, stirring for 20-40min under the condition of 200-250r/min, centrifuging at the rotating speed of 8000-10000r/min after stirring is finished for 15-20min, collecting a solid phase, and freeze-drying at-40 to-30 ℃ for 12-15h to obtain the modified graphene. The invention further provides a scheme that the particle size of the nano aluminum powder is 20-50nm, and the vacuum degree is less than or equal to 10Pa in the freeze drying process. As a further scheme of the invention, the chemical components of the duplex stainless steel matrix comprise ：C≤0.03%、Si0.6-0.8%、Mn5.0-5.5%、P≤0.025%、S≤0.003%、Cr21.0-22.0%、Ni1.3-1.5%、Mo0.15-0.2%、Cu0.1-0.15%、N0.2-0.25%, balance Fe and unavoidable impurities in percentage by mass. As a further scheme of the invention, the particle size of the nano titanium nitride is 50-100nm. The invention also provides a heat treatment process of the corrosion-resistant enhanced duplex stainless steel, which comprises the following steps: s701, weighing all raw materials according to parts by weight, putting the raw materials into a high-speed mixer, and mixing the raw materials for 15-20min at 25-30 ℃ and 800-1000r/min to obtain mixed raw materials; Adding the mixed raw materials into a vacuum induction furnace, vacuumizing until the vacuum degree