High-strength and high-precision small-modulus gear forming method

Abstract

The invention relates to a high-strength and high-precision small-modulus gear forming method which comprises the following steps: S1, preparing metal powder which comprises the following components in percentage by weight: 10-20% of Cr; 8%-16% of Co; 5%-12% of Ni; 4%-8% of Mo; 3%-5% of W; 3%-5% of V; and the balance of Fe. S2, metal powder and a binding agent are mixed to be prepared into feed; s3, the feed is injected into a gear injection blank and a sintering setter plate injection blank made of the same material; s4, brushing zirconium oxide liquid on the sintering setter plate injection blank, and placing the gear injection blank on the sintering setter plate injection blank; s5, performing catalytic degreasing; and S6, the sintering bearing plate degreased blank on which the gear degreased blank is placed is put into a sintering furnace to be sintered, and finally a gear sintered blank is obtained. Zirconium oxide liquid is brushed to prevent the gear and the sintered setter plate from being adhered together, the gear production efficiency is improved, and meanwhile the gear has excellent mechanical property, physical property and high precision grade.

Description

Technical Field

[0001] The invention relates to a method for preparing a small-module gear, and in particular to a method for forming a high-strength and high-precision small-module gear. Background Art

[0002] High-strength, high-precision, small-module gear injection molding technology is an emerging technology that combines high-precision manufacturing with advanced material applications. It is mainly used to meet the growing demand of modern industry for high-strength, small-size and high-precision mechanical parts. The background of this technology involves innovation and development in multiple fields, including material science, machining, injection molding technology and precision manufacturing processes.

[0003] First of all, the development and application of high-strength steel materials is one of the core backgrounds of this technology. High-strength steel has excellent mechanical properties, such as high strength, high hardness and good wear resistance, making it an ideal material for manufacturing gears used in high-load and high-stress environments. However, traditional processing technology is difficult to give full play to the advantages of high-strength steel in the manufacture of small-module gears, especially under the premise of ensuring gear accuracy, which poses a challenge to the application of high-strength steel in the field of small-module gears.

[0004] Secondly, the development of injection molding technology has provided new possibilities for the manufacture of high-precision, high-strength steel small-module gears. Injection molding technology is widely used in the processing and manufacturing of plastics and certain metal materials, but its application in the field of high-strength steel still needs to overcome several technical difficulties. This includes how to ensure the uniformity and density of the material during the injection molding process, and how to control the thermal stress and deformation during the molding process to ensure the accuracy and strength of the final product.

[0005] In general, the development of high-precision, high-strength steel small modulus gear injection molding technology is a response to the application of high-strength materials and precision manufacturing needs. The successful application of this technology not only helps to improve the performance of gear products, but also promotes technological progress in related industrial fields and meets the needs of modern industry for high-performance, miniaturized mechanical components. Summary of the invention

[0006] The purpose of the present invention is to provide a high-strength, high-precision, small-module gear forming method, which significantly improves the mechanical properties of the material, especially the strength and wear resistance, by optimizing the proportion of each component of the material, and is suitable for use in high-load and high-stress environments, and relates to a new type of setter plate processing method, wherein the formula of the zirconium oxide liquid is a mixture of zirconium oxide powder and ethanol in a weight percentage of 1:2. By coating the zirconium oxide liquid on the setter plate, the gear can be effectively prevented from adhering to the setter plate during the sintering process, thereby improving the consistency, yield rate and surface quality of the gear.

[0007] The technical solution to achieve the purpose of the present invention is: the present invention comprises the following steps:

[0008] S1. Prepare metal powder, wherein the metal powder comprises the following components by weight percentage: Cr: 10%-20%; Co: 8%-16%; Ni: 5%-12%; Mo: 4%-8%; W: 3%-5%; V: 3%-5%; and the rest is Fe;

[0009] S2, mixing the metal powder prepared in step S1 with a binder to prepare a feed;

[0010] S3, injecting the feed into a gear injection blank and a sintered support plate injection blank of the same material respectively;

[0011] S4, brushing the sintered setter plate injection blank with zirconium oxide liquid, and placing the gear injection blank on the sintered setter plate injection blank;

[0012] S5, catalytically debinding the gear injection blank and the sintering support plate injection blank together to form a gear debinding blank and a sintering support plate debinding blank, and the gear debinding blank is placed on the sintering support plate debinding blank;

[0013] S6. Put the degreased blank of the sintering support plate on which the degreased blank of the gear is placed into a sintering furnace for sintering, and finally obtain a sintered blank of the gear; the sintered blank of the gear is the final product.

[0014] Furthermore, the weight percentage of the metal powder in the above feed is 85% to 95%, and the weight percentage of the binder is 5% to 15%; the mixing temperature in the feed preparation is 195° C., and the mixing time is 120 minutes.

[0015] Furthermore, in the above step S3, the modulus of the injection-molded gear blank is 0.2; the size of the sintered support plate blank is 50mm*50mm*2mm; and the injection temperature of the gear blank is 160-250°C.

[0016] Furthermore, the zirconium oxide liquid comprises zirconium oxide powder and ethanol, and the weight percentage ratio of zirconium oxide powder to ethanol is 1:2.

[0017] Furthermore, in the above step S5, the catalytic medium for catalytic degreasing is oxalic acid, the degreasing time is 240 minutes, and the oxalic acid flow rate is 3 g / min. The oxalic acid catalysis ensures its excellent mechanical properties and the use of the same material sintering plate ensures its shrinkage consistency.

[0018] Furthermore, in the above step S6, the sintering temperature is 1390° C. and the holding time is 4 hours.

[0019] The present invention has positive effects: the gears prepared by the present invention have the following characteristics:

[0020] (1) Improve the strength and wear resistance of gears; the use of a specific metal powder formula (containing Cr, Co, Ni, Mo, W, V, etc.) can significantly improve the mechanical strength and wear resistance of gears, so that the molded gears can exhibit excellent performance under high load and high stress conditions.

[0021] (2) Improve material utilization: Accurately control the mixing temperature, injection temperature and material ratio to optimize the fluidity and filling properties of the material, reduce material waste, improve material utilization efficiency and reduce production costs.

[0022] (3) Ensure the quality and precision of finished products: By brushing zirconium oxide liquid on the setter plate, the gear is prevented from sticking to the setter plate during the sintering process, thereby improving the yield and surface quality of the gear. In addition, precisely controlled sintering parameters (such as temperature and holding time) ensure the dimensional accuracy and structural integrity of the gear.

[0023] (4) Improve production efficiency: Optimized steps and processing methods, such as the use of polymer binders and automated catalytic degreasing, can improve production efficiency, reduce manual operations and time consumption in the production process, and thus shorten the production cycle.

[0024] (5) Consistency and repeatability: Standardized process flow and parameter control ensure the consistency and repeatability of each batch of gears, which is suitable for large-scale production and batch supply, meeting the requirements of high quality standards.

[0025] (6) Nickel, as a toughening agent, can significantly improve the toughness and fracture resistance of gears. Especially in low temperature environments, nickel can effectively slow down the growth rate of grains and refine the grain structure, thereby improving the mechanical properties and fatigue resistance of the material. In addition, nickel can also improve the corrosion resistance of gears and extend their service life.

[0026] The main role of chromium in high-strength gears is to enhance hardness and wear resistance. Chromium can form stable carbides with carbon, such as Cr23C6. The dispersion and precipitation of these carbides further enhance the surface hardness and wear resistance of the gears. In addition, chromium can also form a dense chromium oxide protective film to improve the stability of gears in high temperature and corrosive environments.

[0027] Cobalt is mainly used to improve the thermal stability and oxidation resistance of gears in high temperature environments. Cobalt can inhibit the coarsening of carbides and maintain the stability of the gear microstructure, thereby improving its long-term working ability under high temperature and high load. In addition, the addition of cobalt also helps to improve the mechanical properties and fatigue resistance of gears.

[0028] Molybdenum plays a reinforcing role in high-strength gears and can effectively improve the strength and toughness of gears. Molybdenum can form high-strength solid solutions and carbides, improving the load-bearing capacity and wear resistance of gears under dynamic loads. In addition, molybdenum can also improve the high-temperature stability of gears and extend their service life.

[0029] In summary, these positive effects make the forming method of the present invention have significant advantages in the production of high-strength, high-precision small-module gears, with shape complexity, dimensional accuracy, high material utilization, flexible control of alloy composition, especially in improving product performance, reducing costs and improving production efficiency. DETAILED DESCRIPTION

[0030] (Example 1)

[0031] The present invention comprises the following steps:

[0032] S1. Prepare metal powder, wherein the metal powder comprises the following components by weight percentage: Cr: 20wt%; Co: 16wt%; Ni: 12wt%; Mo: 8wt%; W: 5wt%; V: 5wt%; and the rest is Fe;

[0033] S2, mixing the metal powder prepared in step S1 with a binder to prepare a feed; the weight percentage of the metal powder in the feed is 92%, and the weight percentage of the binder is 8%; the components of the binder include 75% polyoxymethylene, 10% polyethylene, 10% polypropylene and 5% stearic acid; the mixing temperature of the metal powder and the binder is 195° C., the mixing time is 120 minutes, and after the mixing is completed, granulation is performed to form a feed;

[0034] S3, injecting the feed into a gear injection blank with a modulus of 0.2 and a sintered support plate injection blank with a size of 50mm*50mm*2mm of the same material; wherein the injection temperature of the gear injection blank is 190°C;

[0035] S4, brushing the sintered setter plate injection blank with zirconium oxide liquid, and placing the gear injection blank on the sintered setter plate injection blank; wherein the zirconium oxide liquid comprises zirconium oxide powder and ethanol, and the weight percentage ratio of the zirconium oxide powder to the ethanol is 1:2;

[0036] S5. Catalytically debind the gear injection blank and the sintering support plate injection blank together to form a gear debinding blank and a sintering support plate debinding blank, and the gear debinding blank is placed on the sintering support plate debinding blank; the catalytic medium for catalytic debinding is oxalic acid, the catalysis is 240 minutes, and the acid feeding amount is 3g / min; the excellent mechanical properties are ensured by oxalic acid catalysis and the same material sintering plate is used to ensure the consistency of its shrinkage;

[0037] S6. Put the degreased blank of the sintering support plate with the degreased blank of the gear into a sintering furnace for sintering at a sintering temperature of 1390° C. for 4 hours to obtain a sintered blank of the gear. The sintered blank of the gear is the final product.

[0038] (Example 2)

[0039] The metal powder in this embodiment comprises the following components in weight percentage: Cr: 10wt%; Co: 8wt%; Ni: 5wt%; Mo: 4wt%; W: 3wt%; V: 3wt%; the rest is Fe; the rest is the same as in Embodiment 1.

[0040] (Example 3)

[0041] The metal powder in this embodiment contains the following components in weight percentage: Cr: 20wt%; Co: 16wt%; Ni: 12wt%; Mo: 8wt%; W: 5wt%; V: 5wt%; the rest is Fe; wherein a sintering support plate of the same material is not injected, and a sintering support plate of 99 porcelain material is used, and the rest is the same as in Example 1.

[0042] (Example 4)

[0043] The metal powder in this embodiment includes the following components in weight percentage: Cr: 10wt%; Co: 8wt%; Ni: 5wt%; Mo: 4wt%; W: 3wt%; V: 3wt%; the rest is Fe; there is no injection sintering plate of the same material, and a sintering plate of 99 porcelain material is used, and the rest is the same as in Example 1.

[0044] (Example 5)

[0045] The metal powder in this embodiment comprises the following components in weight percentage: Cr: 15wt%; Co: 12wt%; Ni: 8wt%; Mo: 6wt%; W: 5wt%; V: 4wt%; the rest is Fe; the rest is the same as in Embodiment 1.

[0046] (Example 6)

[0047] In this embodiment, the metal powder contains the following components in weight percentage: Cr: 15wt%; Co: 12wt%; Ni: 8wt%; Mo: 6wt%; W: 5wt%; V: 4wt%; the rest is Fe; wherein a sintering support plate of the same material is not injected, and a sintering support plate of 99 porcelain material is used, and the rest is the same as in Embodiment 1.

[0048] Examples 1 to 6 are compared as follows:

[0049]

[0050]

[0051] The present invention has successfully developed a molding method for high-strength, high-precision, small-module gears by optimizing the metal powder formula, binder composition and processing technology. Experimental results show that this method not only significantly improves the mechanical properties of the gears, but also ensures the high precision and high hardness of the product.

[0052] Among the six examples, Example 1 and Example 3 using sintered setter plates of the same material showed excellent mechanical properties and precision. Specifically, the yield strength of Example 1 reached 1620MPa, the elongation was 6.5%, the hardness was 46HRC, and the precision grade was 7; the yield strength of Example 3 was 1580MPa, the elongation was 6%, the hardness was 45HRC, and the precision grade was also 7. These data show that the metal powder formula with high proportions of Cr, Co, Ni, Mo, W, V and other elements and the use of sintered setter plates of the same material can help significantly improve the comprehensive performance and manufacturing precision of gears.

[0053] In contrast, although the yield strength and elongation of Example 4 and Example 6 using 99 porcelain material setter plates are slightly reduced, the precision grade is relatively poor, only 10, and the hardness is 39HRC and 37HRC respectively. This shows that the 99 porcelain material sintered setter plate can also ensure the good performance of the product under high precision requirements.

[0054] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-strength, high-precision small-module gear forming method, characterized in that The following steps are involved: S1. Prepare metal powder, wherein the metal powder comprises the following components by weight percentage: Cr: 10%-20%; Co: 8%-16%; Ni: 5%-12%; Mo: 4%-8%; W：3％-5％； V：3％-5％； The rest is Fe; S2, mixing the metal powder prepared in step S1 with a binder to prepare a feed; S3, injecting the feed into a gear injection blank and a sintered support plate injection blank of the same material respectively; S4, brushing the sintered setter plate injection blank with zirconium oxide liquid, and placing the gear injection blank on the sintered setter plate injection blank; S5, catalytically debinding the gear injection blank and the sintering support plate injection blank together to form a gear debinding blank and a sintering support plate debinding blank, and the gear debinding blank is placed on the sintering support plate debinding blank; S6. Put the degreased blank of the sintering support plate on which the degreased blank of the gear is placed into a sintering furnace for sintering, and finally obtain a sintered blank of the gear; the sintered blank of the gear is the final product.

2. A high-strength, high-precision small-module gear forming method according to claim 1, characterized in that: The weight percentage of the metal powder in the feed is 85% to 95%, and the weight percentage of the binder is 5% to 15%. The mixing temperature in the feed preparation is 195° C., and the mixing time is 120 minutes.

3. A high-strength, high-precision small-module gear forming method according to claim 1, characterized in that: In the step S3, the modulus of the injection-molded gear blank is 0.2; the size of the sintered support plate blank is 50mm*50mm*2mm; and the injection temperature of the gear blank is 160-250°C.

4. A high-strength, high-precision small-module gear forming method according to claim 1, characterized in that: The zirconium oxide liquid comprises zirconium oxide powder and ethanol, and the weight percentage ratio of the zirconium oxide powder to the ethanol is 1:

2.

5. A high-strength, high-precision small-module gear forming method according to claim 1, characterized in that: In step S5, the catalytic medium for catalytic degreasing is oxalic acid, the degreasing time is 240 minutes, and the oxalic acid flow rate is 3 g / min.

6. A high-strength, high-precision small-module gear forming method according to claim 1, characterized in that: In step S6, the sintering temperature is 1390° C. and the holding time is 4 hours.

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