A high-strength iron-nickel alloy feedstock for metal powder injection molding and a high-strength iron-nickel alloy prepared therefrom.

Abstract

This invention relates to the field of iron-nickel alloy manufacturing technology, and in particular to a high-strength iron-nickel alloy feedstock for metal powder injection molding and a high-strength iron-nickel alloy prepared using the same. The high-strength iron-nickel alloy feedstock for metal powder injection molding is composed of 90±1 wt% alloy powder and 10±1 wt% binder; the alloy powder is composed of carbonyl iron powder and iron-nickel alloy powder; the Ni content in the alloy powder is 8±0.5 wt%; the iron-nickel alloy powder is one or a combination of Fe-Ni16, Fe-Ni20, Fe-Ni30, Fe-Ni36, and Fe-Ni50. The high-strength iron-nickel alloy prepared by this invention has high sintering hardness, good uniformity of tempered metallographic structure and good toughness, which is beneficial to improving the comprehensive mechanical properties and wear resistance of the high-strength iron-nickel alloy, and solves the problem of poor uniformity and toughness of the tempered metallographic structure in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of iron-nickel alloy manufacturing technology, and in particular to a high-strength iron-nickel alloy feedstock for metal powder injection molding and a high-strength iron-nickel alloy prepared therefrom. Background Technology

[0002] High-strength iron-nickel alloys possess excellent corrosion resistance, thermal stability, dimensional stability, high yield strength, and tensile strength. They can withstand significant external forces and deformations while maintaining good ductility and toughness. They are suitable for applications requiring high strength, toughness, and wear resistance, such as laptops, power tools, and smart locks.

[0003] Fe-Ni8 iron-nickel alloy is used to manufacture hinges, brackets, and other parts in laptops, power tools, and smart locks. These parts are characterized by complex structures, small dimensions, and high precision, making them unsuitable for conventional machining. Currently, metal powder injection molding (MIM) is the primary production method. Specifically, spherical iron and nickel powders with a particle size of 5-20µm are uniformly mixed with a binder and then kneaded to obtain a feedstock. The feedstock is then injection molded into a blank, which is subsequently degreased, sintered, and tempered to obtain the iron-nickel alloy component. Existing iron-nickel alloys suffer from poor uniformity of the tempered metallographic structure and poor toughness. Therefore, this invention provides a high-strength iron-nickel alloy feedstock for metal powder injection molding and a high-strength iron-nickel alloy prepared using it. Summary of the Invention

[0004] To address the issues of poor uniformity and toughness of tempered metallographic structure in existing high-strength iron-nickel alloys, this invention provides a high-strength iron-nickel alloy feedstock for metal powder injection molding and a high-strength iron-nickel alloy prepared using the same.

[0005] The present invention provides a high-strength iron-nickel alloy feedstock for metal powder injection molding, which is achieved through the following technical solution:

[0006] A high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90±1wt% alloy powder and 10±1wt% binder; the alloy powder is composed of carbonyl iron powder and iron-nickel alloy powder; the Ni content in the alloy powder is 8±0.5wt%.

[0007] The high-strength iron-nickel alloy prepared in this invention has high sintering hardness, good uniformity of tempered metallographic structure and toughness, which is beneficial to improving the comprehensive mechanical properties and wear resistance of the high-strength iron-nickel alloy and solves the problem of poor uniformity and toughness of tempered metallographic structure in the prior art.

[0008] Preferably, the particle size distribution of the iron-nickel alloy powder is 1–75 µm; the iron-nickel alloy powder is one or a combination of Fe-Ni16 alloy powder, Fe-Ni20 alloy powder, Fe-Ni30 alloy powder, Fe-Ni36 alloy powder, and Fe-Ni50 alloy powder, which allows the nickel powder to be uniformly dispersed inside the high-strength iron-nickel alloy, giving the high-strength iron-nickel alloy good uniformity of tempered metallographic structure and toughness, which is beneficial to its comprehensive mechanical properties and wear resistance, and solves the problem of poor uniformity and toughness of tempered metallographic structure in the prior art.

[0009] Preferably, the particle size distribution of the iron-nickel alloy powder is 1–15 µm.

[0010] Preferably, the iron-nickel alloy powder is Fe16Ni alloy gas atomized powder, and the median diameter D of the Fe16Ni alloy gas atomized powder is... 50 It is 5–15 µm.

[0011] The chemical composition of the Fe16Ni iron-nickel alloy powder is as follows: 0.5-1.5wt% Mo, 0.4-0.6wt% C, 13.00-15.00wt% Ni, 1.00-3.00wt% Cr, 1.00-3.00wt% Cu, <0.38wt% O, with the balance being Fe and unavoidable impurities.

[0012] By controlling the particle size and type of iron-nickel alloy powder, the comprehensive mechanical properties and wear resistance of high-strength iron-nickel alloys can be improved.

[0013] Preferably, the high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.6-90.8 wt% alloy powder and 9.2-9.4 wt% binder.

[0014] Preferably, the alloy powder is composed of 50 wt% carbonyl iron powder and 50 wt% Fe16Ni alloy gas atomization powder.

[0015] The high-strength iron-nickel alloy prepared by the above technical solution has good uniformity and toughness in its tempered metallographic structure, and possesses excellent mechanical properties, toughness, and wear resistance.

[0016] Preferably, the particle size distribution of the iron-nickel alloy powder is 1-15µm; the iron-nickel alloy powder is Fe-Ni36 alloy powder, which is Invar36 alloy spherical powder, UNS K93600 alloy gas atomized powder, or UNS K93601 alloy gas atomized powder.

[0017] By controlling the particle size and type of iron-nickel alloy powder, the comprehensive mechanical properties and wear resistance of high-strength iron-nickel alloys can be improved, while also having a lower coefficient of thermal expansion, giving high-strength iron-nickel alloys better dimensional stability.

[0018] Preferably, the high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.6-90.8 wt% alloy powder and 9.2-9.4 wt% binder.

[0019] Preferably, the alloy powder is composed of 77.77–78.15 wt% carbonyl iron powder and 21.85–22.23 wt% Fe–Ni36 alloy powder.

[0020] The high-strength iron-nickel alloy prepared by the above technical solution has good uniformity and toughness in its tempered metallographic structure, and possesses excellent mechanical properties, toughness, and wear resistance.

[0021] Preferably, the adhesive is prepared from the following raw materials in parts by weight: 80-90 parts of polyoxymethylene, 5-10 parts of skeleton agent, 3-5 parts of compatibilizer EVA, 1-3 parts of lubricant, and 1-3 parts of stearic acid dispersant; the skeleton agent is one of polyolefin, PP, HDPE, and PS; and the lubricant is one of PETS and EBS.

[0022] By adopting the above technical solution, catalytic degreasing can be facilitated, the carbon content in high-strength iron-nickel alloys can be controlled, and the mechanical properties, wear resistance and toughness of high-strength iron-nickel alloys can be improved.

[0023] The present invention provides a method for preparing a high-strength iron-nickel alloy feedstock for metal powder injection molding, which is achieved through the following technical solution:

[0024] A method for preparing a high-strength iron-nickel alloy feedstock for metal powder injection molding includes the following steps:

[0025] Step 1, Mixing: Accurately metered carbonyl iron powder and iron-nickel alloy powder are placed into a conical mixer and mixed for at least 2 hours to obtain alloy powder;

[0026] Step 2: Mix the alloy powder prepared in Step 1 with the binder at a mass ratio of (90±1):(10±1) to obtain a uniform high-strength iron-nickel alloy feedstock for metal powder injection molding.

[0027] Preferably, in step two, the alloy powder prepared in step one and the binder are added to a mixer at a mass ratio of (90±1):(10±1) and mixed. The mixing temperature is 190±5℃, the mixing time is 60±5min, and the screw speed of the mixer is 30±2r / min.

[0028] The preparation method of high-strength iron-nickel alloy feedstock for metal powder injection molding provided in this invention is relatively simple and easy to operate, and is convenient for large-scale production.

[0029] The present invention provides a method for preparing a high-strength iron-nickel alloy feedstock for metal powder injection molding, which is achieved through the following technical solution:

[0030] A high-strength iron-nickel alloy feedstock prepared using a high-strength iron-nickel alloy feedstock for metal powder injection molding is specifically prepared by the following steps:

[0031] Step 1, Mixing: Accurately metered carbonyl iron powder and iron-nickel alloy powder are placed into a conical mixer and mixed for at least 2 hours to obtain alloy powder;

[0032] Step 2: Mix the alloy powder prepared in Step 1 with the binder at a mass ratio of (90±1):(10±1) to obtain a uniform high-strength iron-nickel alloy feedstock for metal powder injection molding.

[0033] Step 3, Injection Molding: The metal powder obtained in Step 2 is injected into the mold using a high-strength iron-nickel alloy feedstock through an injection molding machine, cooled and shaped to obtain a blank;

[0034] Step 4, catalytic degreasing: The catalyst is nitric acid, the temperature is 110~120℃, the acid inlet rate is 4~6ml / min, and the degreasing time is 300±30min;

[0035] Step 5, sintering process: Place the catalytically degreased blank in a graphite vacuum sintering furnace, sinter at a temperature of 1250±50℃ under a vacuum atmosphere, and hold for 120±10 min.

[0036] Step 6, heat treatment: cryogenic treatment at -190~-180℃ for 120±10min, naturally cooled to room temperature, followed by tempering at 200℃ for 60±5min, and naturally cooled to room temperature to obtain a high-strength iron-nickel alloy.

[0037] The method for preparing high-strength iron-nickel alloy feedstock provided in this invention is relatively simple and easy to operate, facilitating large-scale production. Furthermore, the cryogenic treatment employed in this invention results in a more complete martensitic transformation, leading to higher hardness in the cryogenically treated iron-nickel alloy material. This improves wear resistance. The high-strength iron-nickel alloy after cryogenic treatment and tempering exhibits good microstructure uniformity and toughness, thus improving its mechanical properties, toughness, and wear resistance.

[0038] Preferably, the sintering procedure of the graphite vacuum sintering furnace in step five is as follows:

[0039] ① Heating rate is 5±0.5℃ / min, room temperature → 300℃, hold for 30±5min;

[0040] ② The heating rate is 2±0.2℃ / min, from 300℃ to 450℃, and the holding time is 30±5min;

[0041] ③ The heating rate is 2±0.2℃ / min, from 450℃ to 600℃, and the holding time is 60±5min;

[0042] ④ The heating rate is 3±0.3℃ / min, from 600℃ to 1050℃, and the holding time is 20±5min;

[0043] ⑤ The heating rate is 10±1℃ / min, from 1050℃ to 1250℃, and the holding time is 120±5min;

[0044] ⑥ The cooling rate is 7.5±1.5℃ / min, from 1250℃ to 800℃;

[0045] ⑦ The cooling rate is 12±2℃ / min, from 800℃ to 80℃.

[0046] Preferably, the injection molding parameters of the injection molding machine in step three are as follows: Injection machine type: hydraulic press; Injection material temperature: nozzle 190℃, second stage 185℃, third stage 180℃, fourth stage 170℃; Mold temperature: 105℃; Injection speed: first stage 40%, second stage 40%; Molding pressure: first stage 80%, second stage 85%; Holding pressure: 60%; Holding time: 1s; Back pressure: 4bar; Cooling time: 10s.

[0047] By adopting the above injection molding parameters, the quality of the prepared blank can be guaranteed, thereby improving the mechanical properties and dimensional stability of high-strength iron-nickel alloys.

[0048] In summary, the present invention has the following advantages:

[0049] 1. The high-strength iron-nickel alloy prepared in this invention has high sintering hardness, good uniformity of tempered metallographic structure and good toughness, which is beneficial to improving the comprehensive mechanical properties and wear resistance of the high-strength iron-nickel alloy and solves the problem of poor uniformity and toughness of tempered metallographic structure in the prior art.

[0050] 2. The preparation method of high-strength iron-nickel alloy feedstock for metal powder injection molding provided in this invention is relatively simple and easy to operate, and is convenient for large-scale production.

[0051] 3. The preparation method of the high-strength iron-nickel alloy feed provided in the invention is relatively simple and easy to operate, making it easy to achieve large-scale production and manufacturing.

[0052] 4. In this invention, cryogenic treatment is used, which results in a more complete martensitic transformation. The cryogenically treated iron-nickel alloy material has higher hardness and improved wear resistance. The high-strength iron-nickel alloy after cryogenic treatment and tempering has good microstructure uniformity and toughness, which improves the mechanical properties, toughness and wear resistance of the high-strength iron-nickel alloy. Attached Figure Description

[0053] Figure 1This is a metallographic diagram of the high-strength iron-nickel alloy in Embodiment 1 of the present invention.

[0054] Figure 2 This is a metallographic diagram of the high-strength iron-nickel alloy in Comparative Example 1 of this invention.

[0055] Figure 3 These are stress-strain curves of the high-strength iron-nickel alloy samples from three examples in Example 1.

[0056] Figure 4 These are stress-strain curves of three high-strength iron-nickel alloy specimens from Comparative Example 1. Detailed Implementation

[0057] To further understand the inventiveness and technical advancements of this invention, the preferred embodiments of this invention will be discussed in detail below with reference to examples and comparative examples.

[0058] Example: A high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90±1 wt% alloy powder and 10±1 wt% binder.

[0059] The alloy powder is composed of carbonyl iron powder and iron-nickel alloy powder, with a Ni content of 8±0.5wt%. Specifically, the particle size distribution of the iron-nickel alloy powder is 1–75µm, and the iron-nickel alloy powder is one or a combination of Fe-Ni16 alloy powder, Fe-Ni20 alloy powder, Fe-Ni30 alloy powder, Fe-Ni36 alloy powder, and Fe-Ni50 alloy powder.

[0060] Preferably, the particle size distribution of the iron-nickel alloy powder is 1–15 µm, and the iron-nickel alloy powder can be selected as Fe16Ni alloy gas atomized powder with a median diameter D. 50 The median diameter is 5–15 µm. 90 The thickness is 18-24µm. The Fe16Ni alloy atomizing powder specifically used is Fe16Ni powder provided by Longding New Material Technology Co., Ltd., grade LD-Fe16Ni, batch number WHP20241218-1. The high-strength iron-nickel alloy feedstock for metal powder injection molding consists of 90.6-90.8wt% alloy powder and 9.2-9.4wt% binder. The alloy powder is composed of 50wt% carbonyl iron powder and 50wt% Fe16Ni alloy atomizing powder.

[0061] Table 1 shows the chemical composition of Fe16Ni powder.

[0062]

[0063] Table 2 shows the physical property parameters of Fe16Ni powder.

[0064]

[0065] Carbonyl iron powder, Jilin Zhuochuang New Materials Co., Ltd., Grade: JCF2-5, Batch No.: TH-25061033, Median diameter D 50 The median diameter is 4.81 µm. 90 The bulk density is 10.80 µm; the loose bulk density is 2.84 g / cm³. 3 Tap density: 4.35 g / cm³ 3 .

[0066] Table 3 is a table showing the chemical composition of carbonyl iron powder.

[0067]

[0068] Preferably, the iron-nickel alloy powder has a particle size distribution of 1–15 µm, and the iron-nickel alloy powder can be selected as Fe-Ni36 alloy powder. The Fe-Ni36 alloy powder is Invar36 alloy spherical powder, UNS K93600 alloy gas-atomized powder, or UNS K93601 alloy gas-atomized powder. UNS K93600 alloy gas-atomized powder is prepared by gas atomization. UNS K93601 alloy gas-atomized powder is prepared by gas atomization. The Invar36 alloy spherical powder is selected from Zhuangmai (Shanghai) Additive Manufacturing Technology Co., Ltd., with an alloy powder particle size of 5–15 µm and a density of 8.20 g / cm³. 3 Specific surface area: 0.213 cm² 2 / g, sphericity >98.5%, loose density: 3.98 g / cm³ 3 Hall flow rate: 19.1s / 50g.

[0069] Preferably, the iron-nickel alloy powder can be Fe-Ni36 alloy powder, and the high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.6-90.8 wt% alloy powder and 9.2-9.4 wt% binder. The alloy powder in the high-strength iron-nickel alloy feedstock for metal powder injection molding consists of 77.77-78.15 wt% carbonyl iron powder and 21.85-22.23 wt% Invar36 alloy spherical powder.

[0070] The adhesive is made from the following raw materials in parts by weight: 80-90 parts of polyoxymethylene, 5-10 parts of skeleton agent, 3-5 parts of compatibilizer EVA, 1-3 parts of lubricant, and 1-3 parts of stearic acid dispersant.

[0071] The skeleton agent is one of polyolefin, PP, HDPE, and PS.

[0072] The lubricant is either PETS or EBS.

[0073] The adhesive formulation has been disclosed in our previously filed invention patent. The adhesive ingredients are shown in Table 4.

[0074] Table 4: Ingredients List of Adhesives

[0075]

[0076] The adhesive is prepared as follows: 85g of polyoxymethylene F20-03, 6.5g of HDPE, 4g of 30E783 maleic anhydride-grafted EVA, 2g of PETS plastic lubricant BRD-PETS, and 1.5g of dispersant stearic acid are mixed at 500rpm for 10min to obtain the adhesive.

[0077] A method for preparing a high-strength iron-nickel alloy feedstock for metal powder injection molding is as follows:

[0078] Step 1, Mixing: Accurately metered carbonyl iron powder and iron-nickel alloy powder are placed into a conical mixer and mixed for at least 2 hours to obtain alloy powder;

[0079] Step two: Mix the alloy powder prepared in step one with the binder at a mass ratio of (90±1):(10±1) to obtain a uniform high-strength iron-nickel alloy feedstock for metal powder injection molding.

[0080] Preferably, in step two, the alloy powder prepared in step one and the binder are added to a mixer at a mass ratio of (90±1):(10±1) and mixed. The mixing temperature is 190±5℃, the mixing time is 60±5min, and the screw speed of the mixer is 30±2r / min. This allows the carbonyl iron powder and the iron-nickel alloy powder to be fully and evenly mixed, thereby ensuring the mechanical properties, toughness, and wear resistance of the high-strength iron-nickel alloy.

[0081] A method for preparing a high-strength iron-nickel alloy using a high-strength iron-nickel alloy feedstock for metal powder injection molding includes the following steps:

[0082] Step 1, Mixing: Accurately metered carbonyl iron powder and iron-nickel alloy powder are placed into a conical mixer and mixed for at least 2 hours to obtain alloy powder;

[0083] Step 2: Add the alloy powder and binder prepared in Step 1 to the internal mixer at a mass ratio of (90±1):(10±1) and mix them. The mixing temperature is 190±5℃, the mixing time is 60±5min, and the screw speed of the internal mixer is 30±2r / min.

[0084] Step 3, Injection Molding: The metal powder obtained in Step 2 is injected into the mold using a high-strength iron-nickel alloy feedstock through an injection molding machine, cooled and shaped to obtain a blank;

[0085] Preferably, the injection molding parameters of the injection molding machine in step three are as follows: Injection machine type: hydraulic press; Injection material temperature: nozzle 190℃, second stage 185℃, third stage 180℃, fourth stage 170℃; Mold temperature: 105℃; Injection speed: first stage 40%, second stage 40%; Molding pressure: first stage 80%, second stage 85%; Holding pressure: 60%; Holding time: 1s; Back pressure: 4bar; Cooling time: 10s.

[0086] Step 4, catalytic degreasing: The catalyst is fuming nitric acid, the temperature is 110~120℃, the acid inlet rate is 4~6ml / min, and the degreasing time is 300±30min;

[0087] Step 5, sintering process: Place the catalytically degreased blank in a graphite vacuum sintering furnace, sinter at a temperature of 1250±50℃ under a vacuum atmosphere, and hold for 120±10 min.

[0088] Preferably, the sintering procedure of the graphite vacuum sintering furnace in step five is as follows:

[0089] ① Heating rate is 5±0.5℃ / min, room temperature → 300℃, hold for 30±5min;

[0090] ② The heating rate is 2±0.2℃ / min, from 300℃ to 450℃, and the holding time is 30±5min;

[0091] ③ The heating rate is 2±0.2℃ / min, from 450℃ to 600℃, and the holding time is 60±5min;

[0092] ④ The heating rate is 3±0.3℃ / min, from 600℃ to 1050℃, and the holding time is 20±5min;

[0093] ⑤ The heating rate is 10±1℃ / min, from 1050℃ to 1250℃, and the holding time is 120±5min;

[0094] ⑥ The cooling rate is 7.5±1.5℃ / min, from 1250℃ to 800℃;

[0095] ⑦ The cooling rate is 12±2℃ / min, from 800℃ to 80℃;

[0096] Step 6, heat treatment: cryogenic treatment at -190~-180℃ for 120±10min, naturally cooled to room temperature, followed by tempering at 200℃ for 60±5min, and naturally cooled to room temperature to obtain a high-strength iron-nickel alloy.

[0097] Example 1: A high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.76 wt% alloy powder and 9.24 wt% binder. The alloy powder consists of 50 wt% carbonyl iron powder JCF2-5 and 50 wt% Fe16Ni alloy gas atomization powder-LD-Fe16Ni.

[0098] A method for preparing a high-strength iron-nickel alloy feedstock for metal powder injection molding is as follows:

[0099] Step 1, Mixing: Accurately measured 50 parts by weight of carbonyl iron powder JCF2-5 and 50 parts by weight of Fe16Ni alloy gas atomization powder-LD-Fe16Ni are placed into a conical mixer and mixed for 2 hours to obtain alloy powder.

[0100] Step 2: Add the alloy powder prepared in Step 1 and the binder to a mixer at a mass ratio of 90.76:9.24 and mix them at a mixing temperature of 190℃ for 60 minutes and a screw speed of 30 r / min to obtain a high-strength iron-nickel alloy feedstock for metal powder injection molding.

[0101] A method for preparing a high-strength iron-nickel alloy using a high-strength iron-nickel alloy feedstock for metal powder injection molding includes the following steps:

[0102] Step 1, Mixing: Accurately measured 50 parts by weight of carbonyl iron powder JCF2-5 and 50 parts by weight of Fe16Ni alloy gas atomization powder-LD-Fe16Ni are placed into a conical mixer and mixed for 2 hours to obtain alloy powder.

[0103] Step 2: Add the alloy powder and binder prepared in Step 1 to a mixer at a mass ratio of 90.76: 9.24 and mix them at a mixing temperature of 190℃ for 60 minutes and a screw speed of 30 r / min to obtain a high-strength iron-nickel alloy feedstock for metal powder injection molding.

[0104] Step 3, Injection Molding: The metal powder obtained in Step 2 is injected into the mold using a high-strength iron-nickel alloy feedstock via an injection molding machine. The injection molding parameters are as follows: Injection machine type: hydraulic press; Injection material temperature: nozzle 190℃, second stage 185℃, third stage 180℃, fourth stage 170℃; Mold temperature: 105℃; Injection speed: first stage 40%, second stage 40%; Molding pressure: first stage 80%, second stage 85%; Holding pressure: 60%; Holding time: 1s; Back pressure: 4bar; Cooling time: 10s. After cooling and molding, a blank is obtained.

[0105] Step 4, catalytic degreasing: The catalyst is 98% fuming nitric acid, the temperature is 115℃, the acid inlet rate is 5ml / min, and the degreasing time is 300min;

[0106] Step 5, Sintering Process: The catalytically degreased blank is placed in a graphite vacuum sintering furnace. Under a vacuum atmosphere, the sintering procedure in the graphite vacuum sintering furnace is as follows:

[0107] ① Heating rate is 5℃ / min, room temperature → 300℃, hold for 30min;

[0108] ② The heating rate is 2℃ / min, from 300℃ to 450℃, and the temperature is maintained for 30 minutes;

[0109] ③ The heating rate is 2℃ / min, from 450℃ to 600℃, and the temperature is maintained for 60 minutes;

[0110] ④ Heating rate is 3℃ / min, 600℃→1050℃, hold for 20min;

[0111] ⑤ The heating rate is 10℃ / min, from 1050℃ to 1250℃, and the temperature is maintained for 120min;

[0112] ⑥ The cooling rate is 7.5℃ / min, from 1250℃ to 800℃;

[0113] ⑦ The cooling rate is 12℃ / min, from 800℃ to 80℃;

[0114] Step 6, heat treatment: cryogenic treatment at -190℃ for 120 minutes, then naturally cooled to room temperature, followed by tempering at 200℃ for 60 minutes, and then naturally cooled to room temperature to obtain a high-strength iron-nickel alloy.

[0115] The difference between Comparative Example 1 and Example 1 is that the iron-nickel alloy feedstock is made of 90.76 wt% alloy powder and 9.24 wt% binder. The alloy powder consists of 92 wt% carbonyl iron powder JCF2-5 and 8.0 wt% nickel hydroxyl powder. The nickel hydroxyl powder, with a particle size of 100 nm, is from Anshan Guanhua Powder Metallurgy Co., Ltd.

[0116] The difference between the preparation method of the iron-nickel alloy and the preparation method of the high-strength iron-nickel alloy prepared by metal powder injection molding in Example 1 is as follows: Step 1, mixing: 92 parts by weight of carbonyl iron powder JCF2-5 and 8 parts by weight of hydroxyl nickel powder are accurately measured and mixed in a conical mixer for 2 hours to obtain alloy powder. The remaining steps are the same.

[0117] For the metallographic diagram of the high-strength iron-nickel alloy in Example 1, please refer to [link / reference needed]. Figure 1 For the metallographic diagram of the iron-nickel alloy in Comparative Example 1, please refer to [link / reference]. Figures 1-2 ,Depend on Figures 1-2It can be seen that the high-strength iron-nickel alloy prepared by using LD-Fe16Ni as iron-nickel alloy powder has good uniformity and toughness of tempered metallographic structure, which solves the problem of poor uniformity and toughness of tempered metallographic structure in existing iron-nickel alloys.

[0118] Table 5: Mechanical test parameters of the high-strength iron-nickel alloy in Example 1

[0119]

[0120] Table 6: Mechanical Test Parameters and Mechanical Properties of the High-Strength Iron-Nickel Alloy in Comparative Example 1

[0121]

[0122] The test was conducted in accordance with GB / T 228.1-2010. The test equipment was the WDW-50 electronic universal testing machine from Jinan Huifa Testing Technology Co., Ltd. The tensile strength, yield strength, and maximum force of the iron-nickel alloy were measured.

[0123] In conjunction with Example 1 and Comparative Example 1, and in conjunction with Tables 5-6 and Figures 3-4 It can be seen that the high-strength iron-nickel alloy prepared in Example 1 has good uniformity of tempered metallographic structure and toughness, which improves the tensile strength, yield strength and fracture toughness of the high-strength iron-nickel alloy.

[0124] To investigate the effect of heat treatment process on high-strength iron-nickel alloy, Comparative Example 2 was set up to conduct a comparative experiment with Example 1 and Comparative Example 2. The difference between Comparative Example 2 and Example 1 is that the preparation method of the high-strength iron-nickel alloy prepared by metal powder injection molding using high-strength iron-nickel alloy feedstock is different in step six, heat treatment: tempering at 200°C for 60 min, followed by natural cooling to room temperature to obtain the high-strength iron-nickel alloy, while the remaining steps are the same.

[0125] Table 7: Hardness parameters of different sections of the iron-nickel alloy in Example 1 and Comparative Examples 1-2

[0126]

[0127] As can be seen from Example 1 and Comparative Example 2, and Table 7, performing a deep cryogenic treatment at -190℃ for 120 minutes before tempering can make the martensitic transformation more complete. The iron-nickel alloy after deep cryogenic treatment in Example 1 has relatively high hardness, and the finished iron-nickel alloy after tempering has even higher hardness, thus improving the wear resistance of the finished iron-nickel alloy.

[0128] The difference between Example 2 and Example 1 lies in the preparation method of the high-strength iron-nickel alloy prepared by injection molding of high-strength iron-nickel alloy using metal powder as feedstock. Specifically, in step four, catalytic degreasing, the catalyst is fuming nitric acid, the temperature is 115°C, the acid inlet flow rate is 5 ml / min, and degreasing is performed for 300 min. Subsequently, the alloy is transferred to a graphite vacuum sintering furnace, heated from room temperature to 600°C at a rate of 5°C / min and held for 120 min, while simultaneously introducing nitrogen at a flow rate of 30.0 L / min. The process involves degreasing the gas, followed by sintering. Nitrogen is removed by evacuation, and sintering is performed under vacuum. The sintering procedure is as follows: ① Heating rate: 3℃ / min, 600℃→1050℃, hold for 20min; ② Heating rate: 10℃ / min, 1050℃→1250℃, hold for 120min; ③ Cooling rate: 7.5℃ / min, 1250℃→800℃; ④ Cooling rate: 12℃ / min, 800℃→80℃. The remaining steps are the same.

[0129] In Example 2, step four of the iron-nickel alloy preparation process uses nitric acid catalytic degreasing + thermocatalytic degreasing + 4-step vacuum sintering to verify the difference in mechanical properties between the high-strength iron-nickel alloy obtained by the preparation process in Example 1 and the high-strength iron-nickel alloy obtained by the preparation process in Example 2.

[0130] Table 8: Test parameters of iron-nickel alloys in Examples 1 and 2

[0131]

[0132] Combining Examples 1 and 2 with Table 8, it can be seen that the catalytic degreasing and sintering processes have a significant impact on the performance of high-strength iron-nickel alloys, and the high-strength iron-nickel alloys obtained by the preparation method provided in Example 1 have relatively better mechanical properties, toughness, and wear resistance.

[0133] The difference between Example 3 and Example 1 is that: a high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.76 wt% alloy powder and 9.24 wt% binder. The alloy powder consists of 77.77 wt% carbonyl iron powder JCF2-5 and 22.23 wt% Invar36 alloy spherical powder.

[0134] The difference in the preparation method of high-strength iron-nickel alloy prepared by metal powder injection molding is as follows: Step 1, mixing: 77.77 parts by weight of carbonyl iron powder JCF2-5 and 22.23 parts by weight of Invar36 alloy spherical powder are put into a conical mixer and mixed for 2 hours to obtain alloy powder. The remaining steps are the same.

[0135] Table 9: Test parameters of iron-nickel alloys in Examples 1 and 3

[0136]

[0137] Combining Examples 1 and 3 with Table 9, it can be seen that the alloy powder composed of 50 wt% carbonyl iron powder and 50 wt% Fe16Ni alloy gas-atomized powder in Example 1 results in a high-strength iron-nickel alloy with relatively better mechanical properties, toughness, and wear resistance. The alloy powder composed of 77.77 wt% carbonyl iron powder and 22.23 wt% Invar36 alloy spherical powder in Example 2 results in a high-strength iron-nickel alloy with a lower coefficient of thermal expansion and better dimensional stability. Therefore, for parts requiring higher precision, the high-strength iron-nickel alloy of Example 2 can be selected.

[0138] As can be seen from Examples 1 and 3 and Table 9, an increase in the Ni content in the iron-nickel alloy powder affects the dispersion uniformity of the iron-nickel alloy powder and carbonyl iron powder, leading to a decrease in the mechanical properties of the high-strength iron-nickel alloy. Therefore, in this invention, Fe-Ni16 alloy powder is used as the feedstock for high-strength iron-nickel alloy in metal powder injection molding to obtain a high-strength iron-nickel alloy with relatively good overall performance. When customers have higher requirements for part precision, Invar36 alloy spherical powder is used as the feedstock for high-strength iron-nickel alloy in metal powder injection molding.

[0139] The difference between Example 4 and Example 1 is that: a high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.76 wt% alloy powder and 9.24 wt% binder. The alloy powder consists of 50 wt% modified carbonyl iron powder and 50 wt% Fe16Ni alloy gas atomizing powder-LD-Fe16Ni.

[0140] The modified carbonyl iron powder consists of 99.5 wt% carbonyl iron powder JCF2-5 and 0.5 wt% Ti3C2T. x Made from MXene nanosheets. Ti3C2T x MXene nanosheets are from Newene Technology Co., Ltd.

[0141] The difference in the preparation method of high-strength iron-nickel alloy using metal powder injection molding for high-strength iron-nickel alloy feedstock lies in: Step 1, preparation of modified carbonyl iron powder: 99.5 parts by mass of carbonyl iron powder JCF2-5 and 0.5 parts by mass of Ti3C2T xMXene nanosheets were poured into a planetary ball mill, and nitrogen was introduced as a protective gas. Zirconia was used as grinding beads for ball milling modification treatment. Specifically, ① the ball milling speed was 400 rpm / 5 min; ② the ball milling speed was 800 rpm / 15 min; ③ the ball milling speed was 200 rpm / 5 min; ④ the ball milling speed was 80 rpm / 5 min, which yielded modified carbonyl iron powder. Subsequently, 50 parts by weight of accurately measured modified carbonyl iron powder JCF2-5 and 50 parts by weight of Fe16Ni alloy gas atomized powder-LD-Fe16Ni were placed in a conical mixer and mixed for 2 hours to obtain alloy powder. The remaining steps were the same.

[0142] Table 10: Test parameters of iron-nickel alloys in Examples 1 and 4

[0143]

[0144] Combining Examples 1 and 4 with Table 10, it can be seen that adding 0.25 wt% Ti3C2T to the iron-nickel alloy... x MXene nanosheets significantly improve the thermal conductivity of iron-nickel alloys and have a positive effect on their tensile strength, yield strength, dimensional stability, and wear resistance, while having a relatively small impact on fracture toughness. The iron-nickel alloy in Example 4 still exhibits relatively good fracture toughness. The improved thermal conductivity of the iron-nickel alloy in Example 4 makes it suitable for the production of iron-nickel alloy parts with relatively high heat dissipation requirements.

[0145] Because of Ti3C2T x MXene nanosheets are relatively expensive. The iron-nickel alloy in Example 4 is in the laboratory stage and mainly meets the high heat dissipation requirements of individual customers for iron-nickel alloy parts.

[0146] This invention employs a specific iron-nickel alloy powder (especially Fe-Ni16 alloy powder) and carbonyl iron powder to form a MIM-specific alloy powder formulation, combined with a specific cryogenic + tempering heat treatment process. The high-strength iron-nickel alloy obtained by the preparation method provided in the specification has high sintering hardness, good uniformity of tempered metallographic structure and toughness, which is beneficial to improving the comprehensive mechanical properties and wear resistance of high-strength iron-nickel alloys. It solves the problem of poor uniformity and toughness of tempered metallographic structure in existing technologies and expands the application range of MIM high-strength iron-nickel alloy materials.

[0147] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A high-strength Fe-Ni alloy produced using a high-strength Fe-Ni alloy feed material for metal powder injection molding, characterized by: The high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90±1 wt% alloy powder and 10±1 wt% binder; The alloy powder is composed of carbonyl iron powder and iron-nickel alloy powder; The content of Ni element in the alloy powder is 8±0.5 wt%; The preparation method of the high-strength iron-nickel alloy comprises the following steps: Step one, mixing: accurately measure the carbonyl iron powder and iron-nickel alloy powder, and mix them in a conical mixer for at least 2 hours to obtain alloy powder; Step two, uniformly mix the alloy powder prepared in step one with the binder in a mass ratio of (90±1):(10±1) to obtain the high-strength iron-nickel alloy feedstock for metal powder injection molding; Step three, injection molding: inject the high-strength iron-nickel alloy feedstock for metal powder injection molding obtained in step two into a mold through an injection molding machine, and cool and shape to obtain a blank; Step four, catalytic debinding: the catalyst is nitric acid, the temperature is 110-120℃, the acid feeding amount is 4-6 ml / min, and the debinding time is 300±30 min; Step five, sintering process: place the blank after catalytic debinding in a graphite vacuum sintering furnace, and sinter at a temperature of 1250±50℃ under vacuum atmosphere for a holding time of 120±10 min; Step six, heat treatment: deep cryogenic treatment at -190 to -180℃ for 120±10 min, natural cooling to room temperature, subsequent tempering treatment at 200℃ for 60±5 min, and natural cooling to room temperature to obtain the high-strength iron-nickel alloy.

2. The high-strength iron-nickel alloy of claim 1, wherein: The sintering procedure of the graphite vacuum sintering furnace in step five is as follows: ① heating rate is 5±0.5℃ / min, room temperature→300℃, holding for 30±5 min; ② heating rate is 2±0.2℃ / min, 300℃→450℃, holding for 30±5 min; ③ heating rate is 2±0.2℃ / min, 450℃→600℃, holding for 60±5 min; ④ heating rate is 3±0.3℃ / min, 600℃→1050℃, holding for 20±5 min; ⑤ heating rate is 10±1℃ / min, 1050℃→1250℃, holding for 120±5 min; ⑥ cooling rate is 7.5±1.5℃ / min, 1250℃→800℃; ⑦ cooling rate is 12±2℃ / min, 800℃→80℃.

3. The high-strength iron-nickel alloy of claim 1, wherein: The particle size distribution of the iron-nickel alloy powder is 1-75µm; the iron-nickel alloy powder is one or a combination of Fe-Ni16 alloy powder, Fe-Ni20 alloy powder, Fe-Ni30 alloy powder, Fe-Ni36 alloy powder, and Fe-Ni50 alloy powder.

4. The high-strength iron-nickel alloy of claim 1, wherein: The particle size distribution of the iron-nickel alloy powder is 1-15 µm; the iron-nickel alloy powder is Fe16Ni alloy gas atomized powder, and the median diameter D 50 is 5-15 µm.

5. The high-strength iron-nickel alloy of claim 4, wherein: The high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.6-90.8 wt% alloy powder and 9.2-9.4 wt% binder; the alloy powder is composed of 50 wt% carbonyl iron powder and 50 wt% Fe16Ni alloy gas-atomized powder.

6. The high-strength iron-nickel alloy of claim 1, wherein: The particle size distribution of the iron-nickel alloy powder is 1-15 µm; the iron-nickel alloy powder is Fe-Ni36 alloy powder, and the Fe-Ni36 alloy powder is Invar36 alloy spherical powder or UNSK93600 alloy gas atomized powder or UNS K93601 alloy gas atomized powder.

7. The high-strength iron-nickel alloy of claim 6, wherein: The high-strength iron-nickel alloy feedstock for metal powder injection molding is made of 90.6-90.8 wt% alloy powder and 9.2-9.4 wt% binder; the alloy powder is composed of 77.77-78.15 wt% carbonyl iron powder and 21.85-22.23 wt% Fe-Ni36 alloy powder.

8. The high-strength iron-nickel alloy of claim 1, wherein: In the second step, the alloy powder prepared in the first step and the binder are added into a banbury mixer at a mass ratio of (90±1):(10±1), the banbury temperature is 190±5℃, the banbury time is 60±5 min, and the screw rotation speed of the banbury mixer is 30±2 r / min.

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