High-corrosion-resistance nickel-based alloy bar and preparation method thereof

Abstract

The invention belongs to the technical field of alloy preparation, and particularly relates to a high-corrosion-resistance nickel-based alloy bar and a preparation method thereof. The preparation method comprises the steps of burdening, vacuum induction melting, electroslag remelting, vacuum consumable triple casting, forging, hot rolling, peeling, coping, polishing, contact annealing, cold drawing, aging heat treatment, straightening, flaw detection and SOB treatment. Trace elements are added through a vacuum induction melting, vacuum consumable melting and electroslag remelting triple melting technology, and a high-purity cast ingot is cast; designing a reasonable deformation and heat treatment process system; and SOB treatment is carried out on the surface, the high-corrosion-resistance K500 alloy bar is prepared, the tensile strength Rm of the bar is larger than or equal to 1100 MPa, the yield strength Rp0.2 is larger than or equal to 950 MPa, the percentage elongation after fracture (4D) A is larger than or equal to 25%, the hardness HB is larger than or equal to 280, the corrosion rate in a hydrochloric acid solution with the concentration being 5-10% is smaller than or equal to 0.01 mm / y, and the use requirement can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy preparation, and particularly relates to a high corrosion-resistant nickel-based alloy rod and a preparation method thereof. Background Art

[0002] Mineral salt accounts for the largest share of my country's edible salt production. In recent years, to improve brine extraction efficiency and for environmental reasons, well-drilled solution mining has gradually replaced traditional chamber solution mining. As brine extraction depths continue to increase in my country, performance requirements for brine extraction equipment are also increasing. The performance requirements for core transmission components are also becoming increasingly stringent. The performance of traditional K500 material is increasingly failing to meet the required requirements (tensile strength Rm ≥ 1100 MPa, yield strength Rp0.2 ≥ 950 MPa, elongation after fracture (4D) A ≥ 25%, hardness HB ≥ 280, corrosion rate ≤ 0.01 mm / y). Therefore, the production of a highly corrosion-resistant and high-performance nickel-based alloy is an urgent challenge. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings of the prior art and provide a highly corrosion-resistant nickel-based alloy rod and its preparation method. To address the technical problem that conventional K500 alloy cannot meet the performance requirements of transmission components in brine mining equipment, the present invention utilizes a triple melting process of vacuum induction melting, vacuum consumable melting, and electroslag remelting, adding trace elements to produce high-purity ingots. A rationally designed deformation and heat treatment process is then applied, followed by surface SOB treatment. This produces highly corrosion-resistant K500 alloy rods with a tensile strength Rm ≥ 1100 MPa, a yield strength Rp0.2 ≥ 950 MPa, an elongation after fracture (4D) A ≥ 25%, a hardness HB ≥ 280, and a corrosion rate ≤ 0.01 mm / y in a 5-10% hydrochloric acid solution. This method meets the highly corrosive requirements of salt mines, significantly extending the service life of key components in brine mining equipment and enhancing economic benefits.

[0004] To achieve the above technical objectives, the technical solution adopted in the embodiment of the present invention is: In a first aspect, an embodiment of the present invention provides a method for preparing a high corrosion-resistant nickel-based alloy rod, comprising the following steps: (1) Ingredients: Weigh the following raw materials in percentage by mass: Ni 63%-64%, Cu 28%-29%, Al 2.5%-3%, Ti 0.5%-0.8%, Mn 1%-1.5%, C 0.15%-0.2%, CuMg2O 0.1%-0.15%, Re 0.05%-0.1%, and the balance is Fe and unavoidable impurity elements; (2) Melting and casting: adopt vacuum induction melting + electroslag remelting + vacuum consumable melting process: put the raw materials Ni, Cu, Al, Ti, Mn, C and Fe into the vacuum induction melting furnace for refining. After refining, add CuMg20 and Re to the furnace water for deoxidation and desulfurization. After cooling, cast, and electroslag remelting + vacuum consumable melting to obtain the molten ingot. The molten ingot is sampled for composition analysis to ensure that the chemical composition requirements are met; (3) Forging: The molten ingot obtained in step (2) is subjected to homogenization heat treatment, and is placed in a heating furnace and heated to 1000-1100°C, and forged to obtain a solid ingot with a specification of Φ50mm-100mm, and water-cooled; (4) Hot rolling: The solid ingot obtained in step (3) is placed in a heating furnace and heated to 1020-1100°C, hot-rolled to obtain bars with a specification of Φ20 mm to Φ60 mm, and water-cooled; (5) Peeling: Peel hot-rolled bars of different specifications, with the peeling amount being a reduction of 1 to 2 mm in the outer diameter of one side; (6) Grinding: Grind the peeled bar in step (5) to remove surface defects and uneven parts of the bar; (7) Polishing: Polishing the bar material after grinding in step (6) by a polishing machine, and the roughness of the polished bar material is less than Ra0.8; (8) Contact annealing: The bar is annealed by a high current annealing device transmitted through a contact brush and water-cooled; (9) Cold drawing: cold drawing machine is used to draw according to different specifications and passes to obtain semi-finished products; (10) Aging heat treatment: use an aging furnace for heat treatment; (11) Straightening: The bar is straightened by a two-roll straightening machine; (12) Flaw detection: The bar is subjected to eddy current and ultrasonic flaw detection; (13) SOB treatment: Use acid oxidation method to treat the surface of the bar to improve its corrosion resistance; (14) Testing: Perform performance testing on the bar material.

[0005] Furthermore, all the raw materials in step (1) are screened, cut into small pieces and dried before being weighed.

[0006] Furthermore, the refining temperature during vacuum induction melting in step (2) is 1450-1550°C, and the casting temperature is 1350-1400°C.

[0007] Furthermore, the homogenization heat treatment in step (3) includes the following steps: heating to 400-600°C and keeping the temperature for 3-5h, heating to 1000-1050°C and keeping the temperature for 24-30h, cooling to 400-500°C at a cooling rate of 10-12°C / h, and then furnace cooling.

[0008] Furthermore, the contact annealing temperature in step (8) is 700-800°C, maintained for 3-5 seconds and then water-cooled.

[0009] Furthermore, in step (9), the single deformation amount of different cold drawing passes is 20% to 25%, the cold drawing speed is 50 mm / s to 80 mm / s, and step (8) is repeated before each cold drawing pass.

[0010] Furthermore, the aging heat treatment in step (10) includes the following steps: heating to 400-450°C and holding for 1-2 hours, heating to 550-600°C and holding for 10-15 hours, cooling to 450-500°C at a cooling rate of 10-12°C / h and holding for 10-15 hours, and then furnace cooling.

[0011] Furthermore, the maximum error of straightness per meter in step (11) is less than 0.08 mm.

[0012] Furthermore, when the surface of the rod is treated by an acidic oxidation method in step (13), 3% to 4% phosphoric acid, 4% to 5% ethanol, 12% to 15% calcium nitrate, 20% to 25% manganese peroxide and water are mixed in percentage by mass and heated to 90 to 110° C. The rod is completely immersed in the obtained mixture for 65 to 75 minutes.

[0013] In a second aspect, an embodiment of the present invention provides a highly corrosion-resistant nickel-based alloy rod, which is prepared by the preparation method described in the first aspect. The nickel-based alloy rod has a tensile strength Rm ≥ 1100 MPa, a yield strength Rp0.2 ≥ 950 MPa, an elongation after fracture (4D) A ≥ 25%, a hardness HB ≥ 280, and a corrosion rate ≤ 0.01 mm / y in a hydrochloric acid solution with a concentration of 5% to 10%.

[0014] The technical solution provided by the embodiment of the present invention has the following beneficial effects: (1) The present invention adopts a triple melting process of vacuum induction melting + vacuum consumable melting + electroslag remelting to add trace elements to cast high-purity ingots; designs a reasonable deformation + heat treatment process system; and performs SOB treatment on the surface to prepare a highly corrosion-resistant K500 alloy bar. The alloy bar has a tensile strength Rm ≥ 1100 MPa, a yield strength Rp0.2 ≥ 950 MPa, an elongation after fracture (4D) A ≥ 25%, a hardness HB ≥ 280, and a corrosion rate ≤ 0.01 mm / y in a hydrochloric acid solution with a concentration of 5-10%.

[0015] (2) The alloy rod obtained by the present invention has excellent corrosion resistance and mechanical properties, and is particularly suitable for highly corrosive environments such as salt mine brine. It can effectively increase the service life of key components of brine mining equipment, reduce maintenance costs, and improve overall economic benefits. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Example 1 A method for preparing a high corrosion-resistant nickel-based alloy rod comprises the following steps: (1) Ingredients: 80 kg of metal raw materials that have been screened, cut into small pieces, and dried are weighed, including the following components by mass percentage: Ni 63.5%, Cu 28.5%, Al 2.7%, Ti 0.7%, Mn 1.3%, C 0.17%, CuMg20 0.13%, Re 0.07%, and the balance is Fe and unavoidable impurity elements; CuMg20 is a copper-magnesium alloy with a Mg content of 20% by mass; (2) Melting and casting: Vacuum induction melting + electroslag remelting + vacuum consumable melting process is used for melting and casting: the raw materials Ni, Cu, Al, Ti, Mn, C and Fe are refined in a vacuum induction melting furnace at 1500℃ for 1h, and then deoxidized and desulfurized by adding CuMg20 and Re to the furnace water. The temperature is cooled to 1380℃ and poured into a φ120mm ingot mold through a circular funnel gate. The ingot is taken out of the furnace 10 minutes after casting, and electroslag remelting + vacuum consumable melting is performed to obtain the final ingot. The ingot is sampled for component analysis. It needs to meet the chemical composition requirements. The two ends of the ingot are cut flat with a sawing machine, the surface is polished to φ115mm, and then ground; (3) Forging: The ingot is subjected to homogenization heat treatment: the temperature is raised to 500 ° C and kept for 4 h, the temperature is raised to 1025 ° C and kept for 27 h, the temperature is cooled to 480 ° C at a cooling rate of 11 ° C / h, and then furnace cooling is completed. After the treatment, the ingot is placed in a heating furnace and heated to 1050 ° C. After forging, a solid billet with a specification of Φ75 mm is obtained, and the billet is water-cooled; (4) Hot rolling: The solid ingot is placed in a heating furnace and heated to 1050°C. The ingot is hot rolled to obtain a bar with a specification of Φ28 mm and then water-cooled. (5) Peeling: Peel the Φ28mm hot-rolled bar to φ25mm; (6) Grinding: Grind the peeled bar to remove surface defects and uneven parts of the bar and improve its surface smoothness to meet the requirements of subsequent processing or use; (7) Polishing: Polish the bar material with a polishing machine to remove peeling marks, etc., and the surface roughness is Ra0.32; (8) Contact annealing: The bar is annealed by a high current annealing device transmitted by a contact brush, heated to 750°C, maintained for 4 seconds, and water-cooled to make the structure more uniform, refine the grains, and improve the plasticity and toughness of the material; (9) Cold drawing: Use a 50T cold drawing machine to perform multi-pass cold drawing on the annealed bar with a single-pass deformation of 23%, and draw it to φ22.22mm at a cold drawing speed of 60mm / s. The polycrystalline die is designed according to the deformation of each pass. Before each drawing, it needs to be contact annealed and water-cooled to restore the physical and mechanical properties of the surface to the state before cold working, and the oxide layer is more uniform and delicate. (10) Aging heat treatment: Use a 160KW trolley-type aging furnace for heat treatment. Heat the bar to 430℃ and keep it for 1.5h, heat it to 585℃ and keep it for 12h, cool it to 480℃ at a cooling rate of 11℃ / h and keep it for 12h, then cool it in the furnace. (11) Straightening: The bar is straightened by a 60-type two-roller straightening machine. The maximum error per meter detected by the testing platform is 0.05 mm, and the diameter is φ22.19 mm; (12) Flaw detection: The bar is subjected to eddy current and ultrasonic flaw detection. Ultrasonic flaw detection complies with GB / T 4162-2022 standard, and eddy current flaw detection complies with GB / T 11260-2023 standard. (13) SOB treatment: Pour 3% phosphoric acid, 5% ethanol, 15% calcium nitrate, 20% manganese peroxide and water into the soaking tank in order by mass percentage, stir evenly, and heat to 100 °C. Place the rod in the soaking tank to ensure complete immersion and keep it for 70 minutes; (14) Inspection: The tensile strength Rm of the high corrosion-resistant nickel-based alloy rod prepared in this example is 1173 MPa, the yield strength Rp0.2 is 985 MPa, the elongation after fracture (4D) A is 28.7%, the hardness HB is 322, and the corrosion rate in 8% hydrochloric acid solution is ≤0.007 mm / y, which can meet the use requirements; The qualified bars were cut into lengths using a sawing machine, and the specifications of the finished high corrosion-resistant nickel-based alloy bars were measured to be Φ22.2 (±0.025) mm*6645 (±0.25) mm.

[0018] Example 2 A method for preparing a high corrosion-resistant nickel-based alloy rod comprises the following steps: (1) Ingredients: Weigh 71 kg of metal raw materials that have been screened, cut into small pieces, and dried, including the following components by mass percentage: Ni 63.5%, Cu 28.5%, Al 2.8%, Ti 0.7%, Mn 1.3%, C 0.17%, CuMg2O 0.13%, Re 0.07%, and the balance is Fe and unavoidable impurities; (2) Melting and casting: Vacuum induction melting + electroslag remelting + vacuum consumable melting process is used for melting and casting: the raw materials Ni, Cu, Al, Ti, Mn, C, and Fe are placed in a vacuum induction furnace at 1500℃ for 1h, and then deoxidized and desulfurized by adding CuMg20 and Re to the furnace water. The temperature is cooled to 1380℃ and poured into a φ120mm ingot mold through a circular funnel gate. After 10 minutes of casting, the furnace is taken out and electroslag remelting + vacuum consumable melting is performed to obtain the final ingot. The ingot is sampled for component analysis. It needs to meet the chemical composition requirements. The two ends of the ingot are cut flat with a sawing machine, the surface is polished to φ115mm, and then polished; (3) Forging: The ingot is subjected to homogenization heat treatment: the temperature is raised to 500 ° C and kept for 4 h, the temperature is raised to 1025 ° C and kept for 27 h, the temperature is cooled to 480 ° C at a cooling rate of 11 ° C / h, and then furnace cooling is completed. After the treatment, the ingot is placed in a heating furnace and heated to 1050 ° C. After forging, a solid billet with a specification of Φ75 mm is obtained, and the billet is water-cooled; (4) Hot rolling: The solid ingot is placed in a heating furnace and heated to 1050°C. The ingot is hot rolled to obtain a bar with a specification of Φ23 mm and then water-cooled. (5) Peeling: Peel the Φ23mm hot-rolled bar to φ20mm; (6) Grinding: Grind the peeled bar to remove surface defects and uneven parts of the bar and improve its surface smoothness to meet the requirements of subsequent processing or use; (7) Polishing: Polish the bar material with a polishing machine to remove peeling marks, etc., and the surface roughness is Ra0.42; (8) Contact annealing: The bar is annealed by a high current annealing device transmitted by a contact brush, heated to 750°C, maintained for 4 seconds, and water-cooled to make the structure more uniform, refine the grains, and improve the plasticity and toughness of the material; (9) Cold drawing: Use a 50T cold drawing machine to perform multiple cold drawing with a single deformation of 23%, and draw to φ17.41mm at a cold drawing speed of 60mm / s. The polycrystalline die is designed according to the deformation of each pass. Before each drawing, it needs to be contact annealed and water-cooled to restore the surface to the physical and mechanical properties before cold working, and the oxide layer is more uniform and delicate; (10) Aging heat treatment: Use a 160KW trolley-type aging furnace for heat treatment: heat the bar to 430℃ and keep it for 1.5h, heat it to 585℃ and keep it for 12h, cool it to 480℃ at a cooling rate of 11℃ / h and keep it for 12h, then cool it in the furnace; (11) Straightening: The bar is straightened by a 60-type two-roller straightening machine. The maximum error per meter detected by the testing platform is 0.06 mm, and the diameter is φ17.39 mm; (12) Flaw detection: The bar is subjected to eddy current and ultrasonic flaw detection. Ultrasonic flaw detection complies with GB / T 4162-2022 standard, and eddy current flaw detection complies with GB / T 11260-2023 standard. (13) SOB treatment: Pour 3% phosphoric acid, 5% ethanol, 15% calcium nitrate, 20% manganese peroxide and water into the soaking tank in order by mass fraction, stir evenly, and heat to 100 °C. Place the rod in the soaking tank to ensure complete immersion and keep it for 70 min. (14) Inspection: The tensile strength Rm of the high corrosion-resistant nickel-based alloy rod prepared in this example is 1189 MPa, the yield strength Rp0.2 is 1032 MPa, the elongation after fracture (4D) A is 28.5%, the hardness HB is 322, and the corrosion rate in 8% hydrochloric acid solution is ≤0.007 mm / y, which can meet the use requirements; The qualified bars were cut into lengths using a sawing machine, and the specifications of the finished high corrosion-resistant nickel-based alloy bars were measured to be Φ17.4 (±0.025) mm*4930 (±0.25) mm.

[0019] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a high corrosion-resistant nickel-based alloy rod, characterized in that: The following steps are involved: (1) Ingredients: Weigh the following raw materials in percentage by mass: Ni 63%-64%, Cu 28%-29%, Al 2.5%-3%, Ti 0.5%-0.8%, Mn 1%-1.5%, C 0.15%-0.2%, CuMg2O 0.1%-0.15%, Re 0.05%-0.1%, and the balance is Fe and unavoidable impurity elements; (2) Melting and casting: adopt vacuum induction melting + electroslag remelting + vacuum consumable melting process: put the raw materials Ni, Cu, Al, Ti, Mn, C and Fe into the vacuum induction melting furnace for refining. After refining, add CuMg20 and Re to the furnace water for deoxidation and desulfurization. After cooling, cast, and electroslag remelting + vacuum consumable melting to obtain the molten ingot. The molten ingot is sampled for composition analysis to ensure that the chemical composition requirements are met; (3) Forging: The molten ingot obtained in step (2) is subjected to homogenization heat treatment, and is placed in a heating furnace and heated to 1000-1100°C, and forged to obtain a solid ingot with a specification of Φ50mm-100mm, and water-cooled; (4) Hot rolling: The solid ingot obtained in step (3) is placed in a heating furnace and heated to 1020-1100°C, hot-rolled to obtain a bar with a specification of Φ20mm-Φ60mm, and water-cooled; (5) Peeling: Peel hot-rolled bars of different specifications, with the peeling amount being a reduction of 1 to 2 mm in the outer diameter of one side; (6) Grinding: Grind the peeled bar in step (5) to remove surface defects and uneven parts of the bar; (7) Polishing: Polishing the bar material after grinding in step (6) by a polishing machine, and the roughness of the polished bar material is less than Ra0.8; (8) Contact annealing: The bar is annealed by a high current annealing device transmitted through a contact brush and water-cooled; (9) Cold drawing: cold drawing machine is used to draw according to different specifications and passes to obtain semi-finished products; (10) Aging heat treatment: use an aging furnace for heat treatment; (11) Straightening: The bar is straightened by a two-roll straightening machine; (12) Flaw detection: The bar is subjected to eddy current and ultrasonic flaw detection; (13) SOB treatment: Use acid oxidation method to treat the surface of the bar to improve its corrosion resistance; (14) Testing: Perform performance testing on the bar material.

2. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: All the raw materials in step (1) are screened, cut into small pieces and dried before being weighed.

3. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: The refining temperature during vacuum induction melting in step (2) is 1450-1550°C, and the casting temperature is 1350-1400°C.

4. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: The homogenization heat treatment in step (3) includes the following steps: heating to 400-600°C and keeping the temperature for 3-5h, heating to 1000-1050°C and keeping the temperature for 24-30h, cooling to 400-500°C at a cooling rate of 10-12°C / h, and then furnace cooling.

5. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: The contact annealing temperature in step (8) is 700-800°C, maintained for 3-5 seconds and then water-cooled.

6. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: In step (9), the single deformation of different cold drawing passes is 20% to 25%, the cold drawing speed is 50 mm / s to 80 mm / s, and step (8) is repeated before each cold drawing pass.

7. The method for preparing a high corrosion resistant nickel-based alloy rod according to claim 1, wherein: The aging heat treatment in step (10) includes the following steps: heating to 400-450°C and holding for 1-2 hours, heating to 550-600°C and holding for 10-15 hours, cooling to 450-500°C at a cooling rate of 10-12°C / h and holding for 10-15 hours, and then furnace cooling.

8. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: The maximum error of straightness per meter in step (11) is less than 0.08 mm.

9. The method for preparing a high corrosion-resistant nickel-based alloy rod according to claim 1, wherein: When the surface of the rod is treated by the acid oxidation method in step (13), 3% to 4% phosphoric acid, 4% to 5% ethanol, 12% to 15% calcium nitrate, 20% to 25% manganese peroxide and water are mixed in percentage by mass and heated to 90 to 110°C. The rod is completely immersed in the obtained mixture for 65 to 75 minutes.

10. A high corrosion resistant nickel-based alloy rod, characterized in that: The nickel-based alloy rod is prepared by the preparation method according to any one of claims 1 to 9, wherein the tensile strength Rm of the nickel-based alloy rod is ≥ 1100 MPa, the yield strength Rp0.2 is ≥ 950 MPa, the elongation after fracture (4D) A is ≥ 25%, the hardness HB is ≥ 280, and the corrosion rate in a hydrochloric acid solution with a concentration of 5% to 10% is ≤ 0.01 mm / y.