Method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method

Abstract

The invention relates to the technical field of anode steel claws, and discloses a method for preparing an anode steel claw alloy material through a powder metallurgy vacuum sintering method, and the method comprises the following steps: S1, adding an Al element and a B element on the basis of a ZG2000-400 formula; and S2, all the element components are mixed and then subjected to compression molding and sintering treatment, and the alloy material is obtained. The anode steel claw alloy material provided by the invention not only meets the basic requirements of ZG200-400, but also is added with two elements of Al and B for microalloying on the basis, and the strength, hardness, corrosion resistance and the like can be improved by utilizing Al and B microalloying.

Description

Technical Field

[0001] The invention relates to the technical field of anode steel claws, in particular to a method for preparing an anode steel claw alloy material by a powder metallurgy vacuum sintering method. Background Art

[0002] At present, China is the country with the largest electrolytic aluminum production in the world. In 2022, the electrolytic aluminum production reached 40 million tons, a record high. Steel claws are key components in the current electrolytic aluminum production and play an important role. Anode steel claws are divided into four claws, six claws, and eight claws. Together with aluminum guide rods and anode carbon blocks, they form the anode guide rod group. Anode steel claws for aluminum electrolytic cells play a significant role. The aluminum in the electrolytic cell will be oxidized at the anode and lose electrons. These electrons will be transmitted to the cathode through the electrolyte in the electrolytic cell. The steel claws contact the anode and introduce current into the aluminum product, so that it is oxidized during electrolysis, thereby producing aluminum ions. Electrolytic aluminum belongs to a high-energy consumption industry. The electricity cost accounts for about 40% of the production cost of aluminum products in the cost of electrolytic aluminum. In addition, the electrolytic aluminum process currently involves high temperature, strong acid and other environments. The claw legs of the anode steel claw will shrink when in use. When it shrinks to a certain extent, it can no longer be used. This is because its resistivity will increase, thus affecting other factors such as yield. Therefore, the anode steel claws need to have the characteristics of corrosion resistance, high temperature resistance, and high conductivity.

[0003] At present, the preparation methods of anode steel claws in my country include forging, casting, welding, powder metallurgy, etc. First, the forging equipment and mold costs of the forging method are high, the initial investment is large, and it is not suitable for producing parts with particularly complex shapes, so the forging shape is limited. In addition, the forging process is complicated and requires it to be carried out under high temperature and high pressure conditions, so the operation is difficult. Second, the casting method is prone to produce pores and inclusions during the casting process, which affects the product quality. At the same time, due to uneven cooling speed, it is easy to produce uneven organization, resulting in fluctuations in mechanical properties. Therefore, the dimensional accuracy and surface quality of the casting are poor, and the subsequent processing cost is high. Third, the welding method is prone to produce defects such as cracks and pores during the welding process, which affects the performance of the parts. The mechanical properties of the welded joints are usually not as good as those of the integrally manufactured parts. Heat treatment and mechanical processing are required after welding to improve the quality of the parts, and the subsequent processing is complicated. Fourth, the powder metallurgy method has a high material utilization rate and almost no material waste. It can also manufacture complex-shaped parts that are difficult to achieve by traditional methods. The obtained parts have a uniform microstructure, no segregation phenomenon, and improved performance. For mass production, the cost is low and the efficiency is high, which is especially suitable for mass production of the same parts. The product has high dimensional accuracy and good surface finish, which reduces the subsequent processing steps. Summary of the invention

[0004] Technical Problems Solved by the Invention

[0005] The invention provides a method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method.

[0006] Technical solution adopted by the present invention

[0007] The invention provides a method for preparing an anode steel claw alloy material by a powder metallurgy vacuum sintering method.

[0008] The anode steel claw alloy material provided by the present invention not only meets the basic requirements of ZG200-400, but also adds two elements, Al and B, for microalloying. The Al and B microalloying can improve the strength, hardness, corrosion resistance and other aspects.

[0009] The reason is:

[0010] First, since aluminum is a strong deoxidizer, it can react with oxygen in molten steel to form stable aluminum oxide (Al2O3) inclusions, thereby effectively reducing the oxygen content in the molten steel and improving the purity of the steel. After reducing the oxygen content, oxide inclusions are reduced, and the toughness and fatigue performance of the steel are improved. In addition, aluminum forms a dense aluminum oxide film on the surface of the steel, which can effectively prevent the invasion of corrosive media, thereby improving its corrosion resistance. Aluminum can form fine dispersed particles such as aluminum nitride and aluminum oxide in steel. These particles can inhibit the growth of austenite grains at the grain boundaries and play a role in refining the grains. After grain refinement, the strength and toughness of the material are significantly improved, and the fatigue resistance of the steel is enhanced.

[0011] Secondly, boron can form a boron atomic layer on the austenite grain boundary, reduce the energy of its grain boundary, reduce the transformation of austenite to ferrite and pearlite, and thus improve the hardenability of steel. After improving the hardenability, the cast steel material can also form a hard martensite structure at a lower cooling rate, thereby improving the strength and hardness of the steel. The presence of boron in steel can promote the precipitation of fine carbides. These carbides are distributed inside the grains and at the grain boundaries, which can effectively pin dislocations, hinder dislocation movement, and increase the hardness and strength of the material. While improving the hardness and strength, the wear resistance of the steel is also improved. In addition, boron can stabilize carbides at high temperatures and prevent them from coarsening, so that the material maintains good mechanical properties under high temperature environments. Therefore, the high-temperature strength and creep resistance of cast steel materials are improved, making them suitable for high-temperature working environments.

[0012] To expand, the specific implementation plan is:

[0013] The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method comprises the following steps:

[0014] S1 adds Al and B elements to the formula of ZG2000-400;

[0015] S2: After mixing the various element components, the alloy material is obtained by pressing and sintering.

[0016] According to some preferred embodiments, the blending is performed by mechanical blending using a ball mill.

[0017] According to some preferred embodiments, the rotation speed of mechanical blending is 150-200 r / min, the mixing time is 1-2 h, and the ball milling ratio is 8:1; the additives are zinc stearate and chlorinated paraffin, accounting for 0.5% and 0.3% of the total sample mass, respectively.

[0018] According to some preferred embodiments, the press molding is performed using a cold isostatic press.

[0019] According to some preferred embodiments, the sintering is performed by vacuum sintering.

[0020] According to some preferred embodiments, vacuum sintering uses a gradient heating method:

[0021] The room temperature is raised to 550-650℃ in 50 minutes and kept at this temperature for 40-90 minutes;

[0022] Heat up to 700-900℃ for 20 minutes and keep warm for 20-50 minutes;

[0023] Heat up to 1100-1300℃ for 50min and keep warm for 80-120min;

[0024] After the insulation is completed, cool to room temperature with the furnace.

[0025] According to some more preferred embodiments, vacuum sintering uses a gradient heating method:

[0026] The room temperature was raised to 600°C in 50 minutes and kept at this temperature for 60 minutes;

[0027] Raise the temperature to 800°C over 20 minutes and keep it at that temperature for 30 minutes;

[0028] Raise the temperature to 1300°C over 50 minutes and keep it at that temperature for 120 minutes;

[0029] After the insulation is completed, cool to room temperature with the furnace.

[0030] According to some preferred embodiments, the debinding temperature of vacuum sintering is 200-400° C., and the holding time is 1 hour.

[0031] According to some preferred embodiments, the raw material components of the alloy material include: C, Si, P, S, Ti, Mn, Cr, Ni, V, Cu, Fe, Al, and B, and the raw material components are high-purity metal powders.

[0032] According to some preferred embodiments, the raw materials of the alloy material include, by mass percentage, Al 0.1-0.3%, Cu 0.1-0.4%, Cr 0.1-0.4%, Si 0.1-0.3%, Mn 0.1-0.4%, C0.1-0.3%, Ni 0.03-0.12%, P 0.02-0.03%, S 0.02-0.035%, Ti 0.01-0.07%, V0.01-0.03%, B 0.01-0.03%, and the balance is Fe and unavoidable impurities.

[0033] The present invention provides an anode steel claw alloy material obtained by the above-mentioned preparation method.

[0034] Beneficial effects achieved by the present invention

[0035] The anode steel claw alloy material provided by the present invention not only meets the basic requirements of ZG200-400, but also adds two elements, Al and B, for microalloying. The Al and B microalloying can improve the strength, hardness, corrosion resistance and other aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the metallographic image of the sample prepared in Example 1;

[0037] Figure 2 This is the metallographic image of the sample prepared in Example 2;

[0038] Figure 3 This is the metallographic image of the sample prepared in Example 3;

[0039] Figure 4 This is the metallographic image of the sample prepared in Example 4;

[0040] Figure 5 This is the metallographic image of the sample prepared in Example 5. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0042] Example 1

[0043] The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method specifically comprises the following steps:

[0044] Step 1: Weigh the raw material components in proportion: C 0.209%, Si 0.1%, P 0.03%, S 0.027%, Ti 0.066%, Mn 0.1%, Cr 0.1%, Ni 0.089%, V 0.03%, Al 0.1%, Cu 0.1%, B 0.02%, and the balance is Fe and unavoidable impurities; zinc stearate is added at 0.5% of the total mass, and chlorinated paraffin is added at 0.3% of the total mass.

[0045] Step 2: After weighing, use a ball mill mechanical mixing equipment to effectively and evenly mix the metal powders of different components, with a rotation speed of 200r / min, a ball milling ratio of 8:1, and a mixing time of 2h until the mixture is uniform.

[0046] Step 3: Place the mixed powder into a cold isostatic press for pressing, with the pressure parameter set to 450 MPa and the holding time set to 10 min. Then let the sample stand for 1 hour to prevent the sample from rebounding.

[0047] Step 4: Sinter the sample in step 3 under vacuum and high temperature. Sintering steps: Place the sample in step 3 into the container of the sintering furnace, place the container in the vacuum sintering furnace, close the furnace door, and ensure that the furnace door is well sealed to ensure the stability of the vacuum environment. Turn on the vacuum pump and start vacuuming. While vacuuming, you can start heating. Gradually adjust the temperature of the sintering furnace to the required sintering temperature. Maintain the temperature stability by adjusting the heating power and temperature controller of the sintering furnace. After sintering, gradually reduce the temperature of the sintering furnace. When the temperature drops to a safe range, take out the sintered material. Sintering procedure: Room temperature is heated to 600℃ for 50min, kept warm for 60min, heated to 800℃ for 20min, kept warm for 30min, heated to 1300℃ for 50min, and kept warm for 120min. Finally, cool to room temperature with the furnace. The debinding temperature of vacuum sintering is 200-400℃, and the holding time is 1h.

[0048] Example 2

[0049] The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method specifically comprises the following steps:

[0050] Step 1: Weigh the raw material components in proportion: Al 0.1%, Cu 0.2%, Cr 0.2%, Si 0.2%, Mn 0.2%, C 0.209%, Ni 0.089%, P 0.03%, S 0.027%, Ti 0.066%, V 0.03%, B 0.02%, the balance is Fe and unavoidable impurities; zinc stearate is added at 0.5% of the total mass, and chlorinated paraffin is added at 0.3% of the total mass.

[0051] Step 2: After weighing, use a ball mill mechanical mixing equipment to effectively and evenly mix the metal powders of different components, with a rotation speed of 200r / min, a ball milling ratio of 8:1, and a mixing time of 2h until the mixture is uniform.

[0052] Step 3: Place the mixed powder into a cold isostatic press for pressing, with the pressure parameter set to 450 MPa and the holding time set to 10 min. Then let the sample stand for 1 hour to prevent the sample from rebounding.

[0053] Step 4: Sinter the sample in step 3 at high temperature in vacuum. Sintering steps: Place the sample in step 3 in the container of the sintering furnace. Place the container in the vacuum sintering furnace, close the furnace door, and ensure that the furnace door is well sealed to ensure the stability of the vacuum environment. Turn on the vacuum pump and start vacuuming. While vacuuming, you can start heating. Gradually adjust the temperature of the sintering furnace to the required sintering temperature. Maintain the temperature stability by adjusting the heating power and temperature controller of the sintering furnace. After sintering, gradually reduce the temperature of the sintering furnace. When the temperature drops to a safe range, take out the sintered material. Sintering procedure: Room temperature is heated to 600℃ for 50min, kept warm for 60min, heated to 800℃ for 20min, kept warm for 30min, heated to 1300℃ for 50min, and kept warm for 120min. Finally, cool to room temperature with the furnace. The debinding temperature of vacuum sintering is 200-400℃, and the holding time is 1h.

[0054] Example 3

[0055] The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method specifically comprises the following steps:

[0056] Step 1: Weigh the raw material components in proportion: Al 0.1%, Cu 0.3%, Cr 0.3%, Si 0.3%, Mn 0.3%, C 0.209%, Ni 0.089%, P 0.03%, S 0.027%, Ti 0.066%, V 0.03%, B 0.02%, and the balance is Fe and unavoidable impurities; zinc stearate is added at 0.5% of the total mass, and chlorinated paraffin is added at 0.3% of the total mass.

[0057] Step 2: After weighing, use a ball mill mechanical mixing equipment to effectively and evenly mix the metal powders of different components, with a rotation speed of 200r / min, a ball milling ratio of 8:1, and a mixing time of 2h until the mixture is uniform.

[0058] Step 3: Place the mixed powder into a cold isostatic press for pressing, with the pressure parameter set to 450 MPa and the holding time set to 10 min. Then let the sample stand for 1 hour to prevent the sample from rebounding.

[0059] Step 4: Sinter the sample in step 3 at high temperature in vacuum. Sintering steps: Place the sample in step 3 in the container of the sintering furnace. Place the container in the vacuum sintering furnace, close the furnace door, and ensure that the furnace door is well sealed to ensure the stability of the vacuum environment. Turn on the vacuum pump and start vacuuming. While vacuuming, you can start heating. Gradually adjust the temperature of the sintering furnace to the required sintering temperature. Maintain the temperature stability by adjusting the heating power and temperature controller of the sintering furnace. After sintering, gradually reduce the temperature of the sintering furnace. When the temperature drops to a safe range, take out the sintered material. Sintering procedure: Room temperature is heated to 600℃ for 50min, kept warm for 60min, heated to 800℃ for 20min, kept warm for 30min, heated to 1300℃ for 50min, and kept warm for 120min. Finally, cool to room temperature with the furnace. The debinding temperature of vacuum sintering is 200-400℃, and the holding time is 1h.

[0060] Example 4

[0061] The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method specifically comprises the following steps:

[0062] Step 1: Weigh the raw material components in proportion: Al 0.2%, Cu 0.3%, Cr 0.4%, Si 0.1%, Mn 0.2%, C 0.209%, Ni 0.089%, P 0.03%, S 0.027%, Ti 0.066%, V 0.03%, B 0.02%, the balance is Fe and unavoidable impurities; zinc stearate is added at 0.5% of the total mass, and chlorinated paraffin is added at 0.3% of the total mass.

[0063] Step 2: After weighing, use a ball mill mechanical mixing equipment to effectively and evenly mix the metal powders of different components, with a rotation speed of 200r / min, a ball milling ratio of 8:1, and a mixing time of 2h until the mixture is uniform.

[0064] Step 3: Place the mixed powder into a cold isostatic press for pressing, with the pressure parameter set to 450 MPa and the holding time set to 10 min. Then let the sample stand for 1 hour to prevent the sample from rebounding.

[0065] Step 4: Sinter the sample in step 3 at high temperature in vacuum. Sintering steps: Place the sample in step 3 in the container of the sintering furnace. Place the container in the vacuum sintering furnace, close the furnace door, and ensure that the furnace door is well sealed to ensure the stability of the vacuum environment. Turn on the vacuum pump and start vacuuming. While vacuuming, you can start heating. Gradually adjust the temperature of the sintering furnace to the required sintering temperature. Maintain the temperature stability by adjusting the heating power and temperature controller of the sintering furnace. After sintering, gradually reduce the temperature of the sintering furnace. When the temperature drops to a safe range, take out the sintered material. Sintering procedure: Room temperature is heated to 600℃ for 50min, kept warm for 60min, heated to 800℃ for 20min, kept warm for 30min, heated to 1300℃ for 50min, and kept warm for 120min. Finally, cool to room temperature with the furnace. The debinding temperature of vacuum sintering is 200-400℃, and the holding time is 1h.

[0066] Example 5

[0067] The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method specifically comprises the following steps:

[0068] Step 1: Weigh the raw material components in proportion: Al 0.2%, Cu 0.4%, Cr 0.3%, Si 0.2%, Mn 0.1%, C 0.209%, Ni 0.089%, P 0.03%, S 0.027%, Ti 0.066%, V 0.03%, B 0.02%, and the balance is Fe and unavoidable impurities; zinc stearate is added at 0.5% of the total mass, and chlorinated paraffin is added at 0.3% of the total mass.

[0069] Step 2: After weighing, use a ball mill mechanical mixing equipment to effectively and evenly mix the metal powders of different components, with a rotation speed of 200r / min, a ball milling ratio of 8:1, and a mixing time of 2h until the mixture is uniform.

[0070] Step 3: Place the mixed powder into a cold isostatic press for pressing, with the pressure parameter set to 450 MPa and the holding time set to 10 min. Then let the sample stand for 1 hour to prevent the sample from rebounding.

[0071] Step 4: Sinter the sample in step 3 at high temperature in vacuum. Sintering steps: Place the sample in step 3 in the container of the sintering furnace. Place the container in the vacuum sintering furnace, close the furnace door, and ensure that the furnace door is well sealed to ensure the stability of the vacuum environment. Turn on the vacuum pump and start vacuuming. While vacuuming, you can start heating. Gradually adjust the temperature of the sintering furnace to the required sintering temperature. Maintain the temperature stability by adjusting the heating power and temperature controller of the sintering furnace. After sintering, gradually reduce the temperature of the sintering furnace. When the temperature drops to a safe range, take out the sintered material. Sintering procedure: Room temperature is heated to 600℃ for 50min, kept warm for 60min, heated to 800℃ for 20min, kept warm for 30min, heated to 1300℃ for 50min, and kept warm for 120min. Finally, cool to room temperature with the furnace. The debinding temperature of vacuum sintering is 200-400℃, and the holding time is 1h.

[0072] Test example

[0073] The finished products prepared in Examples 1 to 5 were used as samples for test measurements.

[0074] Resistivity test steps:

[0075] (1) First, the 5 mm × 5 mm × 25 mm microalloy steel claws were coarsely ground to a fine film using 60 mesh, 400 mesh, 800 mesh, 1200 mesh, and 2000 mesh sandpaper;

[0076] (2) polishing one side of the microalloy and then ultrasonically cleaning it with acetone;

[0077] (3) Perform tests at three points on each claw, perform tests at each point twice, and take the average value.

[0078] Antioxidant performance measurement experimental steps:

[0079] (1) Take a 5 mm × 5 mm × 25 mm microalloy steel claw sample, grind it roughly with 60 g sandpaper to remove the rust on the surface, and then clean it with alcohol;

[0080] (2) Weighing steel claw;

[0081] (3) Place the steel claw samples in crucibles and place them in a pit furnace. Raise the temperature by 100°C every 20 minutes until the temperature reaches 600°C and keep the temperature for 4 hours.

[0082] (4) After the steel claw is removed from the furnace at 600°C and air-cooled, it is weighed and the weights before and after corrosion are compared.

[0083] Corrosion resistance measurement experimental steps:

[0084] (1) Take a 10 mm × 10 mm × 25 mm microalloy steel claw sample, grind it with 60 g sandpaper to remove the rust on the surface, and then clean it with alcohol;

[0085] (2) Weighing steel claw;

[0086] (3) Place the steel claw samples in crucibles, add 40 g of the top material powder into the crucibles, place them in a pit furnace, increase the temperature by 100 °C every 20 minutes, and heat to 600 °C for 4 hours;

[0087] (4) After the steel claw is removed from the furnace at 600°C and air-cooled, it is weighed and the weights before and after corrosion are compared.

[0088] The measurement results are shown in Table 1.

[0089] Table 1

[0090]

[0091] It can be seen from the results in Table 1 that the steel claw alloy material prepared by the present invention has high density, good resistivity and corrosion resistance and meets the use requirements.

[0092] At the same time, the metallographic images of the samples obtained in Examples 1 to 5 were measured, and the results were as follows: Figures 1 to 5 shown.

Claims

1. A method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering, characterized in that: The steps include: S1 adds Al and B elements to the formula of ZG2000-400; S2 After the various element components are mixed, they are pressed into shape and sintered to obtain an alloy material.

2. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering according to claim 1, characterized in that: The blending was carried out mechanically using a ball mill.

3. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method according to claim 2, characterized in that: The rotation speed of mechanical blending is 150-200 r / min, the mixing time is 1-2 h, the ball milling ratio is 8:1, and the additives are zinc stearate and chlorinated paraffin, which account for 0.5% and 0.3% of the total sample mass, respectively.

4. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering according to claim 1, characterized in that: The pressing molding is carried out by using a cold isostatic press; the pressure is 400-500MPa, the holding time is 5-10min, and the sample standing time is 1-2h.

5. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method according to claim 1, characterized in that: The sintering is carried out by vacuum sintering.

6. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method according to claim 5, characterized in that: Vacuum sintering uses a gradient heating method: The room temperature is raised to 550-650℃ in 50 minutes and kept at this temperature for 40-90 minutes; Heat up to 700-900℃ for 20 minutes and keep warm for 20-50 minutes; Heat up to 1100-1300℃ for 50min and keep warm for 80-120min; After the insulation is completed, cool to room temperature with the furnace.

7. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering according to claim 6, characterized in that: The debinding temperature of vacuum sintering is 200-400℃, and the holding time is 1h.

8. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering method according to any one of claims 1 to 7, characterized in that: The raw material components of the alloy material include: C, Si, P, S, Ti, Mn, Cr, Ni, V, Cu, Fe, Al, and B, and each raw material component is a high-purity metal powder.

9. The method for preparing anode steel claw alloy material by powder metallurgy vacuum sintering according to claim 8, characterized in that: The raw materials of the alloy material include, by mass percentage, Al 0.1-0.3%, Cu 0.1-0.4%, Cr 0.1-0.4%, Si 0.1-0.3%, Mn 0.1-0.4%, C 0.1-0.3%, Ni 0.03-0.12%, P 0.02-0.03%, S0.02-0.035%, Ti 0.01-0.07%, V 0.01-0.03%, B 0.01-0.03%, and the balance is Fe and unavoidable impurities.

10. An anode steel claw alloy material obtained by the preparation method according to any one of claims 1 to 9.

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