Low-density steel induction tooth and manufacturing method thereof

Abstract

The invention belongs to the technical field of mechanical components, and discloses a low-density steel induction tooth and a manufacturing method thereof. The low-density steel induction tooth comprises the following chemical components in percentage by mass: 0.7%-1.1% of C, 5%-11% of Al, 0.3%-0.9% of Si, 10%-15% of Mn, 3%-5% of Ni, 0.3%-0.8% of V, 0.001%-0.002% of Ce and the balance of Fe. The manufacturing method of the low-density steel induced tooth comprises the following steps: preparing materials; manufacturing an induction tooth type shell; melting the raw materials to form molten steel; deoxidizing and deslagging the molten steel; the mass percent contents of Al, Ce and Fe in the molten steel are adjusted to meet the set requirements of the components of the low-density steel induction teeth; molten steel is poured, and induction teeth are formed; and carrying out water toughening treatment on induced teeth. By controlling the chemical components of the low-density steel, the content of Mn in the steel is reduced, and the strength of the steel is guaranteed; the content of microalloy elements in the steel is controlled, the machinability of the steel is improved by adding rare earth, the rare earth adding time is accurately controlled in the smelting process, and the quality of the induced teeth is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical components and relates to a low-density steel induction tooth and a manufacturing method thereof. Background Art

[0002] With the development of the industrial age, environmental problems such as global warming and energy depletion have become increasingly obvious. The International Energy Outlook report points out that about 23% of carbon dioxide emissions come from automobile transportation, and by 2050, this value will double again; in addition, transportation is the largest end user of oil and other liquid fuels, accounting for more than 50%. Therefore, reducing carbon dioxide emissions and fuel consumption rates is a challenge facing the vehicle industry. One of the most important ways to achieve this goal is to reduce the weight of the vehicle body structure. Taking the A-class car as an example, its body-in-white weight is about 350kg. If the body structure is reduced by 10%, it can save 6% to 8% of fuel and reduce exhaust emissions by 5% to 6%. Therefore, lightweighting is the future development path of the vehicle industry.

[0003] At present, the induction gear for construction machinery and vehicles is mainly forged from 42CrMo steel with a density of 7.8g / cm 3 There are more than 300 parts in a single vehicle. Compared with the weight of the whole vehicle, the proportion of the parts is larger than that of other structural parts. It is very necessary to reduce the weight of the structural parts. Fe-Mn-Al-C high-strength steel is a widely studied low-density steel. When 1% Al is added to the steel, the density decreases by 0.101g / cm 3 ; For every 1% C added to steel, the density decreases by 0.41g / cm 3 ; For every 1% addition of Mn in steel, the density decreases by 0.0086g / cm 3 , density can reach 6.2g / cm 3 -7.2g / cm 3 .

[0004] The high Mn and Al content of Fe-Mn-Al-C low-density steel easily reacts with O and S during the smelting process, reducing the internal quality of the material. To prevent oxidation, a vacuum induction furnace must be used for smelting. At the same time, the high C, Mn, and Al content results in poorer machinability and weldability of the material than traditional steel materials. At present, low-density steel is mainly in the form of plates, but cracking is prone to occur during plate processing and welding, limiting the promotion and use of low-density steel in lightweight manufacturing of structural parts. Summary of the invention

[0005] (I) Purpose of the invention

[0006] The purpose of the present invention is to provide a low-density steel induction tooth and a manufacturing method thereof, adopt low-density steel to replace traditional high-strength steel to realize lightweight manufacturing of induction teeth, and manufacture low-density steel induction teeth by casting to reduce the processing workload of low-density steel structural parts. At the same time, by regulating the chemical composition and heat treatment process on the basis of Fe-Mn-Al-C low-density steel, the processability of low-density steel is improved, so as to realize low-cost and efficient manufacturing of low-density steel induction teeth.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention provides a low-density steel induction tooth, the chemical composition and mass percentage of the induction tooth are: C 0.7-1.1%, Al 5-11%, Si0.3-0.9%, Mn 10-15%, Ni 3-5%, V0.3-0.8%, Ce 0.001-0.002%, and the balance is Fe.

[0009] The present invention also provides a method for manufacturing a low-density steel induction tooth, which comprises the following steps:

[0010] S1. Prepare materials

[0011] Prepare the raw materials required for smelting, the raw materials contain the components and impurities of the low-density steel induction tooth;

[0012] S2. Induction gear shell manufacturing

[0013] Prepare an induced tooth shell according to the three-dimensional model of the induced tooth;

[0014] S3, raw materials melt to form molten steel

[0015] Add the raw materials prepared in step S1 into the medium frequency induction furnace and melt them all;

[0016] S4. Deoxidation and slag removal of molten steel

[0017] Add ferrosilicon to the molten steel to deoxidize the steel and perform multiple slag collection and deslagging processes;

[0018] S5, adjusting the mass percentage contents of Al, Ce and Fe in the molten steel to meet the set requirements of the low-density steel induction tooth composition;

[0019] S6, pouring molten steel to induce tooth forming;

[0020] S7, induced tooth water toughening treatment.

[0021] Wherein, in step S1, the components of the low-density steel induction tooth include, by mass percentage, C 0.7-1.1%, Al 5-11%, Si 0.3-0.9%, Mn 10-15%, Ni3-5%, V 0.3-0.8%, Ce 0.001-0.002%, and the remainder is Fe.

[0022] Among them, in step S2, a wax mold is manufactured by 3D printing according to the three-dimensional model of the induced tooth, and then the wax mold is dipped in an aqueous solution of quartz sand and zircon sand of different particle sizes to form a shell with a thickness of 5mm-8mm on the surface. The shell is placed in a heating furnace and heated at 850℃-950℃ for 2h-3h. After all the wax in the shell is melted and evaporated, an induced tooth shell is formed.

[0023] Among them, in step S3, the raw materials prepared in step S1 are added into the medium frequency induction furnace and heating is started. The power is continuously increased during the heating process until the temperature reaches 1610° C. to 1680° C., so that all the raw materials are melted.

[0024] Among them, in step S4, ferrosilicon is added to the molten steel to deoxidize the steel; at the same time, a slag collecting agent is added to the surface of the steel liquid to gather impurities inside the steel liquid on the surface of the medium frequency induction furnace, and the impurities are fished out by tools. The slag collecting process is repeated many times until the surface of the steel liquid is visually pure and free of impurities. At this time, the chemical composition of the steel liquid is tested online.

[0025] Among them, in step S5, the difference between the actual content of Al in the chemical composition tested in step S4 and the set value is compared, and aluminum wire is added to the molten steel to make the mass percentage content of Al reach the set value; rare earth alloy is added to the molten steel to adjust the mass percentage content of Ce and Fe in the molten steel to reach the set value.

[0026] Wherein, in step S6, after rare earth is added for 1 to 2 minutes, the molten steel is poured into the induction tooth shell at a pouring temperature of 1520 to 1610°C.

[0027] Among them, in step S6, after the induction tooth is cast and formed, a sawing machine is used to cut the riser.

[0028] Among them, in step S7, after the riser processing, the low-density steel induction tooth is subjected to water toughening treatment; the water toughening treatment includes: keeping warm at 950℃~1050℃ for 0.5h~1h, cooling in oil; then keeping warm at 690℃ for 0.2~0.3h, cooling in water, to obtain the final state of the induction tooth.

[0029] (III) Beneficial effects

[0030] The low-density steel induction tooth and its manufacturing method provided by the above technical solution have the following advantages:

[0031] Beneficial effects:

[0032] (1) By controlling the chemical composition of low-density steel, the Mn content in the steel is reduced and the strength of the steel is guaranteed;

[0033] (2) Control the content of microalloying elements in steel, add rare earth to improve the processability of steel, accurately control the time of rare earth addition during the smelting process, and improve the quality of induced teeth;

[0034] (3) Improve the chemical composition of low-density steel, determine the appropriate addition time and method, and achieve a high aluminum alloy content;

[0035] (4) The strength of low-density steel can reach 900MPa-1100MPa; the weight of low-density steel induction teeth is reduced by about 10% compared with the induction teeth made of 42CrMo material. DETAILED DESCRIPTION

[0036] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with embodiments.

[0037] This embodiment first provides a low-density steel induction tooth, whose chemical composition and mass percentage are: C 0.7-1.1%, Al 5-11%, Si 0.3-0.9%, Mn 10-15%, Ni 3-5%, V 0.3-0.8%, Ce 0.001-0.002%, and the balance is Fe.

[0038] Based on the chemical composition of the above-mentioned easy-to-process low-density steel, this embodiment manufactures low-density steel induction teeth through a medium-frequency induction furnace and 3D printing sand molds to achieve overall weight reduction of the vehicle.

[0039] The method for manufacturing the low-density steel induction tooth comprises the following steps:

[0040] S1. Prepare materials

[0041] Prepare the raw materials required for smelting, the raw materials contain the components and impurities of the low-density steel induction tooth. The components of the low-density steel induction tooth, according to mass percentage, include: C0.7-1.1%, Al 5-11%, Si 0.3-0.9%, Mn 10-15%, Ni 3-5%, V 0.3-0.8%, Ce 0.001-0.002%, and the balance is Fe.

[0042] In this embodiment, return materials and waste materials are used when preparing raw materials. By mass percentage, 40% is Fe-Mn-Al-C low-density steel plate return material (chemical composition: C1.0-1.2%, Al 10-12%, Si 0.3-0.9%, Mn 25-30%, Fe as the balance), and 60% is high manganese steel processing waste. The weight of single furnace molten steel is 200 kg. Based on this part of raw materials, the composition of the low-density steel induction tooth containing the above-mentioned components and percentages is obtained.

[0043] S2. Induction gear shell manufacturing

[0044] The wax mold is manufactured by 3D printing according to the three-dimensional model of the induced tooth, and then the wax mold is dipped in an aqueous solution of quartz sand and zircon sand of different particle sizes to form a shell with a thickness of 5-8mm on the surface. Finally, the shell is placed in a heating furnace and heated at 850-950℃ for 2-3h. After the wax in the shell is completely melted and evaporated, the induced tooth shell is taken out.

[0045] S3, raw materials melt to form molten steel

[0046] The raw materials prepared in step S1 are added into the medium frequency induction furnace and heating is started. The power is continuously increased during the heating process until the temperature reaches 1610° C. to 1680° C., at which time all the raw materials are melted.

[0047] S4. Deoxidation and slag removal of molten steel

[0048] Ferrosilicon is added to the molten steel to deoxidize it. At the same time, a slag collector is added to the surface of the steel to gather the impurities inside the steel on the surface of the medium frequency induction furnace. The impurities are fished out by tools. The slag collection process is repeated many times until the surface of the steel is visually pure and free of impurities. At this time, the chemical composition of the steel is tested online.

[0049] S5. Adjust the mass percentage of Al, Ce and Fe in the molten steel to meet the requirements of the low-density steel induction tooth composition setting.

[0050] Compare the difference between the actual content of Al in the chemical composition tested in step S4 and the set value, add aluminum wire to the molten steel to make the mass percentage content of Al reach the set value; add rare earth alloy to the molten steel to adjust the mass percentage content of Ce and Fe in the molten steel to the set value.

[0051] The rare earth alloy used in this embodiment contains Ce and Fe elements, and has a density of about 7.8 g / cm 3 , which is comparable to the density of steel, so it will not float above the molten steel.

[0052] S6, molten steel pouring, induced tooth forming

[0053] 1 to 2 minutes after rare earth is added, the molten steel is poured into the induction tooth shell at a pouring temperature of 1520 to 1610°C.

[0054] The required induced teeth were obtained, and the test density was 7.2g / cm 3 After smelting, the riser is cut by a conventional sawing machine, which is easy to process and has good surface quality.

[0055] S7, induced tooth water toughening treatment

[0056] After the riser processing, the low-density steel induction tooth is subjected to water toughening treatment. The water toughening treatment includes: keeping at 950℃~1050℃ for 0.5h~1h, cooling in oil; then keeping at 690℃ for 0.2~0.3h, cooling in water, and obtaining the final state of the induction tooth.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-density steel induction tooth, characterized in that: The chemical composition and mass percentage of the induced tooth are: C 0.7-1.1%, Al 5-11%, Si 0.3-0.9%, Mn 10-15%, Ni 3-5%, V 0.3-0.8%, Ce 0.001-0.002%, and the balance is Fe.

2. A method for manufacturing a low-density steel induction tooth, characterized in that: The following steps are involved: S1. Prepare materials Prepare the raw materials required for smelting, the raw materials contain the components and impurities of the low-density steel induction tooth; S2. Induction gear shell manufacturing Prepare an induced tooth shell according to the three-dimensional model of the induced tooth; S3, raw materials melt to form molten steel Add the raw materials prepared in step S1 into the medium frequency induction furnace and melt them all; S4. Deoxidation and slag removal of molten steel Add ferrosilicon to the molten steel to deoxidize the steel and perform multiple slag collection and deslagging processes; S5, adjusting the mass percentage contents of Al, Ce and Fe in the molten steel to meet the set requirements of the low-density steel induction tooth composition; S6, pouring molten steel to induce tooth forming; S7, induced tooth water toughening treatment.

3. The method for manufacturing a low-density steel induction tooth according to claim 2, characterized in that: In step S1, the components of the low-density steel induction tooth include, by mass percentage, C 0.7-1.1%, Al 5-11%, Si 0.3-0.9%, Mn 10-15%, Ni 3-5%, V 0.3-0.8%, Ce 0.001-0.002%, and the remainder is Fe.

4. The method for manufacturing a low-density steel induction tooth according to claim 3, characterized in that: In step S2, a wax mold is manufactured by 3D printing according to the three-dimensional model of the induced tooth, and then the wax mold is dipped in an aqueous solution of quartz sand and zircon sand of different particle sizes to form a shell with a thickness of 5mm-8mm on the surface. The shell is placed in a heating furnace and heated at 850℃-950℃ for 2h-3h. After all the wax in the shell is melted and evaporated, an induced tooth shell is formed.

5. The method for manufacturing a low-density steel induction tooth according to claim 4, characterized in that: In step S3, the raw materials prepared in step S1 are added into a medium frequency induction furnace and heating is started. The power is continuously increased during the heating process until the temperature reaches 1610° C. to 1680° C., so that all the raw materials are melted.

6. The method for manufacturing a low-density steel induction tooth according to claim 5, characterized in that: In step S4, ferrosilicon is added to the molten steel to deoxidize the steel. At the same time, a slag collecting agent is added to the surface of the steel to collect impurities inside the steel on the surface of the medium frequency induction furnace. The impurities are fished out by tools. The slag collecting process is repeated many times until the surface of the steel is visually pure and free of impurities. At this time, the chemical composition of the steel is tested online.

7. The method for manufacturing a low-density steel induction tooth according to claim 6, characterized in that: In step S5, the actual content of Al in the chemical composition tested in step S4 is compared with the set value, and aluminum wire is added to the molten steel to make the mass percentage content of Al reach the set value; rare earth alloy is added to the molten steel to adjust the mass percentage content of Ce and Fe in the molten steel to reach the set value.

8. The method for manufacturing low-density steel induction teeth according to claim 7, characterized in that: In step S6, after rare earth is added for 1 to 2 minutes, the molten steel is poured into the induction tooth shell at a pouring temperature of 1520 to 1610°C.

9. The method for manufacturing a low-density steel induction tooth according to claim 8, characterized in that: In step S6, after the induction tooth is cast and formed, a sawing machine is used to cut the riser.

10. The method for manufacturing low-density steel induction teeth according to claim 9, characterized in that: In step S7, after the riser processing, the low-density steel induction tooth is subjected to water toughening treatment; the water toughening treatment includes: keeping at 950℃~1050℃ for 0.5h~1h, cooling in oil; then keeping at 690℃ for 0.2~0.3h, cooling in water, to obtain the final state of the induction tooth.