A high-blast-pressure engine valve seat ring alloy material, a preparation method and application thereof

Abstract

This invention relates to the field of valve seat material technology, specifically disclosing a high-explosion-pressure engine valve seat alloy material, its preparation method, and its application. This high-explosion-pressure engine valve seat alloy material, through the rational use of various elements, ensures wear resistance and high-temperature resistance while meeting the high strength and high hardness requirements of high-explosion-pressure engines for valve train components. The high-explosion-pressure engine valve seat alloy material prepared according to this invention possesses corrosion resistance, fatigue resistance, oxidation resistance, wear resistance, high-temperature resistance, and high-temperature hardness. It solves the problem that existing valve seat materials, which typically consist of ordinary Fe-C based powder with a high proportion of alloy powder added, cannot meet the high strength and high hardness requirements of high-explosion-pressure engines for valve train components. Furthermore, the preparation method provided by this invention can be used to prepare other types of products, showing broad market prospects.

Description

Technical Field

[0001] This invention relates to the field of valve seat material technology, specifically to a high-explosive-pressure engine valve seat alloy material, its preparation method, and its application. Background Technology

[0002] With the continuous development of science and technology, the gradual improvement of people's awareness of energy conservation and emission reduction, and the actual needs of long-distance freight and special operations, the research and development of high-performance engines has become a hot topic. At present, new high-explosion-pressure engines with advantages such as "high torque, high power, high thermal efficiency, and low emissions" are quickly gaining market favor and being widely applied.

[0003] Generally, the performance of engine components has a significant impact on engine performance. Common engine components include the crankshaft and connecting rod mechanism, valve train, cooling system, lubrication system, fuel system, starting system, and ignition system. Among these, the valve seat is a core component of the engine's valve train, its function being to match the valves to provide fresh air for combustion and expel exhaust gases. During engine operation, the valve seat endures frequent impacts from the valves at high temperatures for extended periods, requiring excellent wear resistance and heat resistance. Existing powder metallurgy valve seat technology commonly improves wear resistance and high-temperature resistance by adding high proportions of various high-temperature and wear-resistant alloying elements, such as Co, Cr, Mo, Ni, W, and V. This involves adding a high proportion of alloy powder to ordinary Fe-C based powder to enhance wear resistance and high-temperature performance.

[0004] However, the existing technical solutions mentioned above have the following drawbacks: In practical applications, although a high proportion of alloy addition can significantly improve high temperature resistance and wear resistance, once the alloy proportion reaches a certain level, it is easy to cause local accumulation of alloying elements (segregation), which in turn leads to quality abnormalities such as insufficient sintering diffusion, low seat ring strength, working surface chipping, and seat ring fracture. This results in the inability to meet the high strength and high hardness requirements of high-explosion-pressure engines for valve train components. Summary of the Invention

[0005] The purpose of this invention is to provide a valve seat alloy material for high-explosive engines, in order to solve the problem mentioned in the background art that existing valve seat materials, in order to improve wear resistance and high-temperature performance, usually add a high proportion of alloy powder to ordinary Fe-C base powder, which cannot meet the high strength and high hardness requirements of high-explosive engines for valve train components.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] A high-explosive engine valve seat alloy material, by mass percentage, is composed of the following components:

[0008] C: 0.9-1.5%, S: 0.2-1.0%, W: 4.0-11.0%, V: 4.0-15.0%, Co: 15.0-33.0%, Mo: 3.0-15.0%, Cr: 3.0-9.0%, Mn: 0.2-1.0%, Cu: 12.0-22.0%, Nb: 0.4-1.5%, with the balance being Fe and unavoidable impurities.

[0009] Another objective of this invention is to provide a method for preparing a high-explosion-pressure engine valve seat alloy material, wherein the method for preparing the high-explosion-pressure engine valve seat alloy material specifically includes the following steps:

[0010] According to the composition ratio of the high-explosive engine valve seat alloy material, the alloy raw materials are mixed, pressed, sintered, copper-infiltrated, cryogenically treated and heat-treated in sequence to obtain the high-explosive engine valve seat alloy material.

[0011] Another objective of this invention is to provide a high-explosive engine valve seat alloy material prepared using the above-described method for preparing high-explosive engine valve seat alloy material.

[0012] Another objective of this invention is to provide the application of the above-mentioned high-explosive-pressure engine valve seat alloy material in the manufacture of engine parts.

[0013] Compared with the prior art, the beneficial effects of the embodiments of the present invention are:

[0014] The high-explosion-pressure engine valve seat alloy material provided in this invention uses C, S, W, V, Co, Mo, Cr, Mn, Cu, Nb, etc. as components. Through the rational use of each element, while ensuring wear resistance and high-temperature resistance, it can meet the high strength and high hardness requirements of high-explosion-pressure engines for valve train components. Among them, the use of W can improve the high-temperature hardness and high-temperature stability of the material. Cr and C form wear-resistant carbides Cr7C3 and oxygen generate dense and stable Cr2O3 and other compounds, which can effectively improve the material's corrosion resistance, fatigue resistance, and oxidation resistance. The Fe-Co-Mo, Fe-V-Cu and other hard alloy reinforcing phases formed after high-temperature copper infiltration further improve the wear resistance, high-temperature resistance and high-temperature hardness of the valve seat. Compared to the industry practice of adding a high proportion (60%-70% total content) of alloy powders such as Co, Cr, Mo, Ni, W, and V to ordinary Fe-C base powder to improve the wear resistance and high-temperature resistance of valve seat rings in order to meet the operating conditions of diesel and gas engines, the high-explosion pressure engine valve seat ring alloy material prepared in this invention possesses corrosion resistance, fatigue resistance, oxidation resistance, wear resistance, high-temperature resistance, and high-temperature hardness. This solves the problem that existing valve seat ring materials, which typically add a high proportion of alloy powder to ordinary Fe-C base powder to improve wear resistance and high-temperature resistance, cannot meet the high strength and high hardness requirements of high-explosion pressure engines for valve train components. Furthermore, the preparation method of the high-explosion pressure engine valve seat ring alloy material provided in this invention is simple and can be used to prepare other types of engine component products with high strength and high hardness requirements, showing broad market prospects. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention.

[0016] Figure 1 Metallographic image (X500) of the high-explosive-pressure engine valve seat alloy material provided in an embodiment of the present invention.

[0017] Figure 2 for Figure 1 The diagram shows the component distribution of the high-explosive-pressure engine valve seat alloy material. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the following embodiments will help those skilled in the art to further understand the embodiments of this invention, but do not limit the embodiments of this invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the embodiments of this invention. These all fall within the protection scope of the embodiments of this invention.

[0019] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0020] First, it should be noted that currently, in order to meet the operating requirements of diesel and gas engines, the industry typically adds a high proportion (total content as high as 60%-70%) of alloy powders such as Co, Cr, Mo, Ni, W, and V to ordinary Fe-C based powder to improve the wear resistance and high-temperature resistance of the valve seat. However, adding a high proportion of alloy powder can easily cause localized accumulation (segregation) of alloy elements. When the engine is running, after continuous knocking and slapping by the valves, the hard alloy is prone to peeling and falling off, and chipping is likely to occur at the sealing surface (working surface) of the valve seat. At the same time, the crush strength of the valve seat is significantly reduced by adding high alloy powder, usually only 450-600 MPa. When the valve seat is pressed into the cylinder head or when the engine is running, breakage often occurs, making it even more difficult to meet the high strength and high hardness requirements of high-explosion-pressure engines for valve train components.

[0021] Therefore, to address the problem that existing valve seat materials typically involve adding a high proportion of alloy powder to ordinary Fe-C based powder to improve wear resistance and high-temperature resistance, which easily leads to localized alloy element accumulation (segregation) and fails to meet the high strength and hardness requirements of high-pressure engines for valve train components, this invention provides an alloy material, specifically a high-pressure engine valve seat alloy material, which, by mass percentage, consists of the following components:

[0022] C: 0.9-1.5%, S: 0.2-1.0%, W: 4.0-11.0%, V: 4.0-15.0%, Co: 15.0-33.0%, Mo: 3.0-15.0%, Cr: 3.0-9.0%, Mn: 0.2-1.0%, Cu: 12.0-22.0%, Nb: 0.4-1.5%, with the balance being Fe and unavoidable impurities.

[0023] Preferably, the high-explosive engine valve seat alloy material is composed of the following components by mass percentage:

[0024] C: 0.9-1.5%, S: 0.5-1.0%, W: 4.0-10.0%, V: 10.0-15.0%, Co: 15.0-20.0%, Mo: 3.0-6.0%, Cr: 3.0-7.0%, Mn: 0.5-1.0%, Cu: 14.0-20.0%, Nb: 1.0-1.5%, with the balance being Fe and unavoidable impurities.

[0025] Preferably, the high-explosive engine valve seat alloy material is composed of the following components by mass percentage:

[0026] C: 1.2-1.5%, S: 0.7-0.8%, W: 6.0-8.0%, V: 13.0-15.0%, Co: 13.0-15.0%, Mo: 4.0-5.0%, Cr: 4.5-5.5%, Mn: 0.8-1.0%, Cu: 14.0-16.0%, Nb: 1.2-1.5%, with the balance being Fe and unavoidable impurities.

[0027] More preferably, the alloy material of the high-explosive engine valve seat ring has a hardness of 50-60 HRC (Rockwell hardness) and a density of 7.6-8.0 g / cm³. 3 The crushing strength is 800-950 MPa.

[0028] This invention also provides a method for preparing a high-explosion-pressure engine valve seat alloy material, the method comprising the following steps:

[0029] According to the composition ratio of the high-explosive-pressure engine valve seat alloy material, the alloy raw materials are mixed, pressed, sintered, copper-infiltrated, cryogenically treated and heat-treated in sequence to obtain the high-explosive-pressure engine valve seat alloy material.

[0030] Furthermore, in the preparation method of the high-explosion-pressure engine valve seat alloy material, the alloy raw materials specifically adopt suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder; in actual operation, after selecting a suitable reinforcing base powder, less than 50% of the total mass of alloy powder is added during mixing, that is, the specific gravity of the reinforcing base powder is greater than that of the alloy powder. After high-temperature copper infiltration, hard alloy reinforcing phases such as Fe-Co-Mo and Fe-V-Cu are formed, thereby obtaining the high-explosion-pressure engine valve seat alloy material.

[0031] This invention utilizes a reinforcing base powder (containing a certain proportion of elements such as W, Cr, V, and Fe) comprising more than 50% of the total mass, with alloy powder added during mixing. After high-temperature sintering, W is dispersed in the matrix, forming a eutectic mixture of high-melting-point and high-hardness carbides WC and W2C, thus improving the material's high-temperature hardness and stability. Cr reacts with C to form wear-resistant carbides Cr7C3, and with oxygen to form dense and stable compounds such as Cr2O3, effectively enhancing the material's corrosion resistance, fatigue resistance, and oxidation resistance. These carbide reinforcing phases are dispersed in the matrix material, strengthening the matrix. Simultaneously, by selecting suitable reinforcing base powders and adding alloy powder comprising less than 50% of the total mass during mixing, hard alloy reinforcing phases such as Fe-Co-Mo and Fe-V-Cu are formed after high-temperature copper infiltration, further improving the wear resistance, high-temperature resistance, and high-temperature hardness of the bearing ring. This results in the preparation of high-explosive engine valve seat alloy material with corrosion resistance, fatigue resistance, oxidation resistance, wear resistance, high temperature resistance and high temperature hardness. When used to prepare valve seat products, it can meet the high strength and high hardness requirements of high-explosive engines for valve train components while ensuring wear resistance and high temperature resistance.

[0032] In another preferred embodiment of the present invention, in the method for preparing the high-explosive-pressure engine valve seat alloy material, the pressing molding involves pressing the mixed powdered alloy raw materials into a density of 6.4-7.0 g / cm³ on a press. 3 The seat ring is formed into a blank; at the same time, the weight of the copper sheet is calculated according to 16%-30% of the weight of the seat ring, and the copper sheet for copper infiltration is pressed.

[0033] It should be noted that the compression molding pressure can be reasonably selected based on existing technology processes, such as compression molding with a pressure of 100-500 MPa, depending on the specific needs. There is no limitation here, as long as it can be compressed to a density of 6.4-7.0 g / cm³. 3 The seat ring blank can be formed.

[0034] As another preferred embodiment of the present invention, in the preparation method of the high-explosive engine valve seat alloy material, the sintering temperature is 1110-1140℃; in actual operation, the valve seat blank and the pressed copper sheet for copper infiltration are stacked alternately and then sintered and copper infiltrated at high temperature at 1110-1140℃ in a pusher furnace or mesh belt furnace.

[0035] In practical applications, high-temperature sintering in a mesh belt furnace accelerates the removal of solid lubricant and provides appropriate carbon compensation, resulting in more uniform heating and less deformation of the sintered parts. High-temperature sintering also improves the diffusion of high-alloy particles within the matrix, leading to higher hardness (50-60 HRC) and a density of 7.6-8.0 g / cm³ for high-pressure engine valve seat rings. 3 The crushing strength is 800-950 MPa.

[0036] As another preferred embodiment of the present invention, in the preparation method of the high-explosive-pressure engine valve seat alloy material, the cryogenic treatment is carried out at -180°C to -160°C after sintering and copper infiltration; specifically, the blank obtained after sintering and copper infiltration can be placed in a liquid nitrogen furnace at -180°C to -160°C for cryogenic treatment.

[0037] In another preferred embodiment of the present invention, in the preparation method of the high-explosive-pressure engine valve seat alloy material, the heat treatment temperature is 500℃-600℃ and the time is 1-6 hours.

[0038] As another preferred embodiment of the present invention, in the preparation method of the high-explosive-pressure engine valve seat alloy material, the heat treatment temperature is 510℃-550℃ and the time is 2-5 hours; specifically, the seat blank after cryogenic treatment can be placed in a heat treatment furnace for heat treatment at 510℃-550℃ for 2-5 hours.

[0039] Preferably, the preparation method of the high-explosive-pressure engine valve seat alloy material includes the following steps:

[0040] (1) Select alloy-containing reinforced tool steel powder and high-quality alloy powder, and weigh and mix the raw material powders according to the designed ratio; (2) Press the mixed powder into a density of 6.4-7.0 g / cm³ on a press. 3 (3) Simultaneously calculate the weight of copper sheets according to 16%-30% of the weight of the seat ring, and press copper sheets for copper diffusion; (4) After the seat ring blank and copper sheets are stacked alternately, they are sintered and copper diffusioned at high temperature in pusher furnace and mesh belt furnace respectively; (5) The sintered blank is placed in a liquid nitrogen furnace at -180℃ to -160℃ for deep cryogenic treatment; (6) The seat ring blank after deep cryogenic treatment is placed in a heat treatment furnace for heat treatment at 510℃-550℃ for 2-5 hours, and then cooled to obtain the high explosion pressure engine valve seat ring alloy material.

[0041] The proportion of reinforced tool steel powder is more than half of the total weight of the valve seat alloy material of the high-explosion-pressure engine, while the total proportion of alloy powder added as a hard phase is less than half. The composition of "more reinforced base powder and less alloy powder" and the matrix reinforcement greatly improve the crushing strength of this material (more than 40% higher than existing high alloy materials). At the same time, the proportion of reinforced base powder is higher than that of added alloy powder, and the reinforcing elements in the reinforced base powder help maintain the relative position of hard alloy particles and the inter-lattice gap, effectively inhibiting lattice distortion, crystal plane slip, and plastic flow, improving the material's resistance to plastic deformation at high temperatures, and preventing hard particles from peeling off or the whole material from breaking under high temperature and external impact.

[0042] This invention also provides a high-explosive engine valve seat alloy material prepared using the above-described method for preparing high-explosive engine valve seat alloy material.

[0043] This invention also provides an application of the above-mentioned high-explosive-pressure engine valve seat alloy material in the manufacture of engine parts.

[0044] In the above applications, the engine components can be parts of the crankshaft and connecting rod mechanism, valve train, cooling system, lubrication system, fuel system, starting system, and ignition system; wherein, the crankshaft and connecting rod mechanism can be connecting rods, crankshafts, bearings, flywheels, pistons, piston rings, piston pins, crankshaft oil seals, etc.; the valve train can be cylinder heads, valve cover covers, camshafts, valves, intake manifolds, exhaust manifolds, air filters, mufflers, three-way catalytic converters, turbochargers, intercoolers, etc.; the cooling system can be a water tank. The system includes components such as a water pump, radiator, fan, thermostat, water temperature gauge, and drain valve; the lubrication system can be an engine lubrication system consisting of an oil pump, oil strainer, oil filter, oil passages, pressure relief valve, oil gauge, pressure sensor, and dipstick; the fuel system can be a fuel tank, fuel gauge, fuel line, fuel filter, fuel pump, carburetor, air filter, intake and exhaust manifolds; the starting system can be a starter motor, ignition switch, and battery; the ignition system can be spark plugs, high-voltage wires, high-voltage coils, and distributor.

[0045] Furthermore, the application of the aforementioned high-explosive engine valve seat alloy material in the preparation of engine valve train mechanisms is preferred. The valve train mechanisms can include valve seats, cylinder heads, valve cover covers, camshafts, valves, intake manifolds, exhaust manifolds, air filters, mufflers, three-way catalytic converters, turbochargers, intercoolers, etc.; especially its application in the preparation of valve seats is widespread.

[0046] More preferably, the high-explosion-pressure engine valve seat alloy material or the high-explosion-pressure engine valve seat alloy material prepared by the above preparation method is particularly suitable as a wear-resistant powder metallurgy valve seat material for preparing high-explosion-pressure engine matrix-reinforced powder metallurgy valve seat materials.

[0047] Furthermore, the manufacturing steps of the high-explosive-pressure engine matrix reinforced powder metallurgy valve seat ring are as follows: (1) Select alloy-containing reinforced tool steel powder and high-quality alloy powder, and weigh and mix the raw material powders according to the designed ratio; (2) Press the mixed powder into a density of 6.4-7.0 g / cm³ on a press. 3 (3) Simultaneously calculate the weight of copper sheets according to 16%-30% of the weight of the seat ring, and press copper sheets for copper diffusion; (4) After the seat ring blank and copper sheets are stacked alternately, they are sintered and copper diffusioned at high temperature in pusher furnace and mesh belt furnace respectively; (5) The sintered blank is placed in a liquid nitrogen furnace at -180℃ to -160℃ for deep cryogenic treatment; (6) The seat ring blank after deep cryogenic treatment is placed in a heat treatment furnace for heat treatment at 510℃-550℃ for 2-5 hours; (7) After heat treatment, 3-5 pieces are extracted to test hardness, density and metallographic structure; (8) The upper and lower end faces of the seat ring are ground on a double end grinder; (9) The outer circle is rough ground on a centerless grinder; (9) The sealing surface, inner circle and inner and outer chamfers are machined on a CNC lathe; (10) The high explosion pressure engine matrix reinforced powder metallurgy valve seat ring is obtained by oil immersion, counting and packaging.

[0048] The technical effects of the high-explosive-pressure engine valve seat alloy material of the present invention will be further explained below by listing specific embodiments.

[0049] Example 1

[0050] A high-explosive engine valve seat ring alloy material is prepared using suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder as alloy raw materials. The specific composition is shown in Table 1. The reinforcing base powder accounts for 40.0% of the total (W: 5.1%, Cr: 4.0%, V: 6.8%, Fe, balance), and the alloy powder accounts for 58.0% of the total (Mo: 12.3%, Co: 31.9%, Nb: 1.0%). The basic additives include C, S, and Mn, accounting for 0.9%, 0.5%, and 0.6% of the total, respectively. The copper infiltration component is calculated as 14% of the valve seat ring weight.

[0051] In this embodiment, the preparation method of the high-explosive engine valve seat alloy material is as follows:

[0052] (1) According to the above-described composition ratio of the high-explosive engine valve seat alloy material, appropriate reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder are used as alloy raw materials. The raw material powders are weighed and mixed according to the designed ratio, wherein the specific gravity of the reinforcing base powder is greater than that of the alloy powder; (2) The mixed powder is pressed into a density of 6.4-7.0 g / cm³ on a press. 3 (3) Simultaneously calculate the weight of copper sheet according to 14% of the weight of the seat ring, and press copper sheet for copper diffusion; (4) After the seat ring blank and the pressed copper sheet for copper diffusion are stacked alternately, they are sintered and copper diffusion are carried out on the mesh belt furnace at high temperature of 1110℃; (5) The sintered blank is placed in a liquid nitrogen furnace at -180℃ to -160℃ for deep cryogenic treatment; (6) The seat ring blank after deep cryogenic treatment is placed in a heat treatment furnace for heat treatment at 540℃ for 2.5 hours, and then cooled to obtain the high explosion pressure engine valve seat ring alloy material.

[0053] Example 2

[0054] A high-explosive-pressure engine valve seat ring alloy material is disclosed, which uses suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder as alloy raw materials. The specific composition is shown in Table 1 and will not be elaborated here. The copper infiltration component is calculated as 14% of the valve seat ring weight.

[0055] In this embodiment, the preparation method of the high-explosive engine valve seat alloy material can be referred to in Embodiment 1, and will not be repeated here.

[0056] Example 3

[0057] A high-explosive-pressure engine valve seat ring alloy material is disclosed, which uses suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder as alloy raw materials. The specific composition is shown in Table 1 and will not be elaborated here. The copper infiltration component is calculated as 14% of the valve seat ring weight.

[0058] In this embodiment, the preparation method of the high-explosive engine valve seat alloy material can be referred to in Embodiment 1, and will not be repeated here.

[0059] Example 4

[0060] A high-explosive-pressure engine valve seat ring alloy material is disclosed, which uses suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder as alloy raw materials. The specific composition is shown in Table 1 and will not be elaborated here. The copper infiltration component is calculated as 16% of the valve seat ring weight.

[0061] In this embodiment, the preparation method of the high-explosive engine valve seat alloy material is as follows:

[0062] (1) According to the above-described composition ratio of the high-explosive engine valve seat alloy material, appropriate reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder are used as alloy raw materials. The raw material powders are weighed and mixed according to the designed ratio, wherein the specific gravity of the reinforcing base powder is greater than that of the alloy powder; (2) The mixed powder is pressed into a density of 6.4-7.0 g / cm³ on a press. 3 (3) Simultaneously calculate the weight of copper sheet according to 16% of the weight of the seat ring, and press copper sheet for copper diffusion; (4) After the seat ring blank and the pressed copper sheet for copper diffusion are stacked alternately, they are sintered and copper diffusion are carried out on the mesh belt furnace at high temperature of 1140℃; (5) The sintered blank is placed in a liquid nitrogen furnace at -180℃ to -160℃ for deep cryogenic treatment; (6) The seat ring blank after deep cryogenic treatment is placed in a heat treatment furnace for heat treatment at 520℃ for 3 hours, and then cooled to obtain the high explosion pressure engine valve seat ring alloy material.

[0063] Example 5

[0064] A high-explosive-pressure engine valve seat ring alloy material is disclosed, which uses suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder as alloy raw materials. The specific composition is shown in Table 1 and will not be elaborated here. The copper infiltration component is calculated as 16% of the valve seat ring weight.

[0065] In this embodiment, the preparation method of the high-explosive engine valve seat alloy material is as follows:

[0066] (1) According to the above-described composition ratio of the high-explosive engine valve seat alloy material, appropriate reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder are used as alloy raw materials. The raw material powders are weighed and mixed according to the designed ratio, wherein the specific gravity of the reinforcing base powder is greater than that of the alloy powder; (2) The mixed powder is pressed into a density of 6.4-7.0 g / cm³ on a press. 3 (3) Simultaneously calculate the weight of copper sheet according to 16% of the weight of the seat ring, and press copper sheet for copper diffusion; (4) After the seat ring blank and the pressed copper sheet for copper diffusion are stacked alternately, they are sintered and copper diffusion are carried out on the mesh belt furnace at high temperature of 1140℃; (5) The sintered blank is placed in a liquid nitrogen furnace at -180℃ to -160℃ for deep cryogenic treatment; (6) The seat ring blank after deep cryogenic treatment is placed in a heat treatment furnace for heat treatment at 520℃ for 3 hours, and then cooled to obtain the high explosion pressure engine valve seat ring alloy material.

[0067] Example 6

[0068] A high-explosive-pressure engine valve seat ring alloy material is disclosed, which uses suitable reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder as alloy raw materials. The specific composition is shown in Table 1 and will not be elaborated here. The copper infiltration component is calculated as 16% of the valve seat ring weight.

[0069] In this embodiment, the preparation method of the high-explosive engine valve seat alloy material is as follows:

[0070] (1) According to the above-described composition ratio of the high-explosive engine valve seat alloy material, appropriate reinforced tool steel powder (as reinforcing base powder) and high-quality alloy powder are used as alloy raw materials. The raw material powders are weighed and mixed according to the designed ratio, wherein the specific gravity of the reinforcing base powder is greater than that of the alloy powder; (2) The mixed powder is pressed into a density of 6.4-7.0 g / cm³ on a press. 3 (3) Simultaneously calculate the weight of copper sheet according to 16% of the weight of the seat ring, and press copper sheet for copper diffusion; (4) After the seat ring blank and the pressed copper sheet for copper diffusion are stacked alternately, they are sintered and copper diffusion are carried out on the mesh belt furnace at high temperature of 1140℃; (5) The sintered blank is placed in a liquid nitrogen furnace at -180℃ to -160℃ for deep cryogenic treatment; (6) The seat ring blank after deep cryogenic treatment is placed in a heat treatment furnace for heat treatment at 520℃ for 3 hours, and then cooled to obtain the high explosion pressure engine valve seat ring alloy material.

[0071] The specific composition of the alloy materials for the valve seat rings of the different high-explosive engines in each embodiment is shown in Table 1.

[0072] Table 1. Raw material addition ratios for different samples

[0073]

[0074] To compare different samples, comparative examples 1-6 were designed as comparative cases. The specific composition and preparation methods of the samples in comparative examples 1-6 are shown in Table 1.

[0075] As shown in Table 1 above, in Examples 1-6, the proportion of alloy powder (mainly containing Co, Mo, V, and Nb) gradually decreased, while the proportion of reinforcing base powder (mainly containing W, Cr, V, and Mo) gradually increased. All examples were sintered in a mesh belt furnace. The first three examples used the same sintering and heat treatment mode, while the latter three examples used a different sintering and heat treatment mode.

[0076] Comparative Examples 1-4 and Examples 1-4 use the same formulation schemes, but different sintering furnaces. Comparative Examples 5 and 6 use the same formulation schemes and sintering furnaces as Comparative Example 4, but with improved copper infiltration rates. In actual sample preparation, the addition of reinforcing base powder, alloy powder, and other components is shown in Table 1. The addition ratios of reinforcing base powder, alloy powder, copper infiltration components, and basic additives can all be obtained from the formulations in Table 1.

[0077] Performance testing

[0078] To determine the compositional distribution of the high-explosion-pressure engine valve seat alloy material prepared in the embodiments of the present invention, the metallographic structure of the high-explosion-pressure engine valve seat alloy material sample prepared in Example 4 was observed after polishing. The obtained metallographic structure photographs are shown below. Figure 1 As shown. According to Figure 1 Analysis of the metallographic photograph (i.e., 500x magnification) of the high-explosion-pressure engine valve seat alloy material shows that... Figure 2 The diagram shows the component distribution of the valve seat alloy material in a high-explosive engine.

[0079] exist Figure 1 and Figure 2 As can be seen, Fe-Co-Mo and Fe-V-Cu are distributed in the alloy steel matrix of the obtained high-explosion-pressure engine valve seat alloy material. By using a method where the specific gravity of the reinforcing base powder is greater than that of the alloy powder, Fe-Co-Mo and Fe-V-Cu hard alloy reinforcing phases are formed after high-temperature copper infiltration. At the same time, solid lubricants that play a lubricating role in alloy preparation are also distributed (existing products can be used, which will not be elaborated here). It exhibits superior wear resistance and durability reliability in the high-temperature, high-pressure, and unlubricated environment of the high-explosion-pressure engine.

[0080] Furthermore, based on the experience of OEM customers in bench tests and road tests, this invention understands that high-explosion-pressure engines and other heavy-duty diesel engines achieve the engine's "high torque, high power, and high thermal efficiency" by increasing the compression ratio of the internal combustion gas. As a result, the engine's thermal load is higher, and the pressure and stress on key components of the valve train, such as valve seats and valves, are greater, requiring higher performance in terms of strength, hardness, wear resistance, and durability.

[0081] To verify the performance of the high-explosion-pressure engine valve seat alloy material obtained in this invention, the high-explosion-pressure engine valve seat alloy materials prepared in Examples 1-6 and Comparative Examples 1-6 were subjected to performance testing and a 100-hour high-temperature rapid grinding experiment. The specific test results are shown in Table 2. The mechanical properties and wear resistance of the valve seat alloy materials in different examples were improved to a certain extent.

[0082] As can be seen from the data in Table 2, the high-explosion-pressure engine valve seat alloy material prepared using the preparation method provided in this embodiment of the invention can effectively improve the material properties. The hardness of the high-explosion-pressure engine valve seat alloy material can reach 50-60 HRC, and the density can reach 7.6-8.0 g / cm³. 3 The crushing strength can reach 800-950 MPa.

[0083] Experimental results show that the seat ring of Example 4 has the best mechanical properties and the best wear resistance.

[0084] Table 2 Experimental Results

[0085]

[0086] This invention uses tool steel powder (mainly containing W, Cr, V, Fe, etc.) with an alloy content ≥20% to replace the original pure iron powder or low alloy powder, improving the high-temperature resistance, wear resistance, and strength of the matrix. Simultaneously, alloys mainly containing Co and Mo are added for dispersion strengthening, forming an Fe-Co-Mo hard alloy wear-resistant phase, enhancing the material's high-temperature hardness and resistance to impact and abrasive wear. The addition of V compounds forms an Fe-V-Cu reinforcing phase, further improving the hardness of the bearing ring. Cu possesses excellent thermal conductivity; using copper infiltration technology, Cu particles melt and infiltrate into the pores during sintering, not only improving the bearing ring's thermal conductivity but also significantly increasing the material's strength. Adding an appropriate amount of solid lubricant MoS2 enhances the material's self-lubricating properties, better adapting to the harsh, unlubricated environment of high-pressure engines and reducing adhesive wear. A small amount of MnS is added to improve the material's machinability.

[0087] It should be noted that the high-wear-resistant powder metallurgy valve seat materials (hereinafter referred to as high-alloy materials) currently used in the industry are generally composed of less than 50% low-alloy base powder (or pure Fe-C alloy powder) and more than 50% high-alloy powder. Because the base powder contains less alloy, the wear resistance and hardness of the matrix are insufficient, thus affecting the overall wear resistance and hardness of the valve seat. At the same time, the material design of "less base powder, more alloy" can easily lead to localized alloy segregation in the valve seat, resulting in poor bonding strength between the alloy and the matrix. The matrix's "cohesive force" on the alloy particles decreases, and under the high-frequency impact of the valve, the crystal faces of the alloy particles on the working surface of the valve seat are prone to slippage, leading to abnormalities such as plastic flow of the valve seat material, alloy particle spalling, and chipping. For high-explosion-pressure engines, under the influence of very high combustion gas explosion pressure and high-frequency spring settling force, the valve seat working surface experiences high contact stress. During valve settling, rotation causes micro-slippage between the valve cone surface and the seat sealing surface. High-alloy materials are subjected to intense impact at temperatures above 400°C. Because the matrix of this material is not reinforced and the bonding force between the alloy hard phase and the matrix is ​​weak, when the radial shear stress exceeds the material's strength limit, the hard phase of the high-alloy material undergoes radial flow and plastic deformation. Simultaneously, the relatively soft matrix is ​​prone to the pear-groove effect and abrasive wear, leading to severe wear of the seat sealing surface until rapid failure. In contrast, the matrix-reinforced material of this invention possesses excellent high-temperature hardness and strength, strengthens the seat matrix, and exhibits good bonding between the matrix and hard phase. It demonstrates superior wear resistance and durability in the high-temperature, high-pressure, and unlubricated environment of high-explosion-pressure engines.

[0088] Based on the above results, the beneficial effects of the embodiments of the present invention are as follows: By using tool steel powder with an alloy content ≥20% (mainly containing W, Cr, V, Fe, etc.), and adding less than 50% alloy powder by weight during mixing, the high temperature resistance, wear resistance, thermal conductivity, strength, hardness, high temperature hardness, impact resistance, and abrasive wear resistance of the material are improved. When used to prepare valve seat ring products, while ensuring wear resistance and high temperature resistance, it can meet the high strength and high hardness requirements of high-explosion-pressure engines for valve train components. Moreover, the preparation method provided by the embodiments of the present invention is simple and has broad market prospects. The high-explosion-pressure engine valve seat ring alloy material described above, or the high-explosion-pressure engine valve seat ring alloy material prepared by the described method, has the following advantages when applied in high-explosion-pressure engines:

[0089] (a) Improve seat ring strength

[0090] (1) Within a certain range, the higher the forming density of the seat ring blank, the higher the compressive strength and wear resistance of the seat ring. The green density of the seat ring should be controlled between 6.5-6.8 g / cm³ during forming. 3 After copper infiltration, the density of the seat ring reaches 7.6-8.2 g / cm³.3 (2) Reinforced base powder is used to improve the overall strength of the matrix and seat ring; (3) The reinforced base powder has a higher specific gravity than the alloy powder, which enhances the "cohesion and binding force" of the matrix for alloy particles and the bonding strength between the matrix and alloy particles; (4) Copper infiltration process is used to fill the pores of the seat ring with copper; (5) Sintering is carried out in a mesh belt furnace, which allows the solid lubricant to be burned off quickly, the high alloy particles to diffuse better in the matrix, and with appropriate carbon compensation, the sintered parts are heated more evenly and deformed less. After cold and heat treatment, the crushing strength of the seat ring reaches 800-950 MPa, which is more than 45% higher than the average crushing strength (550-600 MPa) of the existing high alloy wear-resistant seat rings.

[0091] (ii) Improve the high-temperature hardness and wear resistance of the seat ring.

[0092] (1) When the temperature of the high-compression ratio combustion gas in the cylinder chamber of a high-explosion-pressure engine often reaches above 400℃, the wear mechanism of the bearing ring is mainly plastic deformation and fatigue spalling, accompanied by varying degrees of adhesive wear. To change this situation, this invention directly adds W (with a high melting point and good high-temperature resistance), Cr (with good oxidation and corrosion resistance), and Mo (with strong hardenability and good wear resistance) in a certain proportion to the strengthening base powder, instead of adding them as a hard phase. W is strengthened by solid solution and dispersion in the strengthening base powder, and after sintering, it generates a eutectic mixture of WC and W2C, which can maintain high hardness and good stability even in high-temperature environments above 1000℃. Cr can form a variety of carbides, such as Cr7C3 with good wear resistance; it can form a dense and stable Cr2O3 passivation film, which effectively improves the corrosion resistance and fatigue resistance of the material; V can refine the grains, and V compounds have high-temperature stability, which can greatly improve the high-temperature hardness of the material. Meanwhile, the presence of W, Cr, and Mo in the base powder can improve the bonding strength of metallic bonds, thereby reducing the plastic deformation and fatigue wear of the material at high temperatures. (2) In addition to improving the strength of the matrix, this invention also adds a certain proportion of alloy powder containing Co, Mo, V, and Nb. Mo is finely dispersed in the matrix, with obvious fine grain and solid solution strengthening effects. Moreover, it can stabilize ferrite in powder metallurgy, improve hardenability and wear resistance of the matrix. Co forms Fe-Co-Mo alloy hard phase with Mo and Fe, and the wear-resistant strengthening phase generated when combined with the matrix further improves the hardness and wear resistance of the material, and enhances the wear resistance of the valve under high-strength and high-frequency impact. V can refine the grains, and the compounds of V have high-temperature stability, which can greatly improve the high-temperature hardness of the material. The hardness of the seat ring after cold and hot treatment of this invention reaches 50-60 HRC.

[0093] It should be noted that high-pressure engines rely on the high temperatures generated by natural compression to cause fuel explosion (gasoline engines rely on spark plug ignition), simultaneously increasing the compression ratio of the internal combustion gases to achieve higher fuel efficiency, stronger torque, and more power. Furthermore, due to the higher thermal load of high-pressure engines, the valve seats and other components bear greater pressure, thus requiring higher strength, hardness, wear resistance, and high-temperature resistance. Previously, high-pressure engine valve seats could only meet these requirements using expensive imported cast steel materials. Therefore, to keep pace with the development of new models by domestic OEMs, increase market share, and showcase the company's technological strength, this invention has developed a high-pressure engine valve seat alloy material. This high-strength, high-hardness, and high-wear-resistant matrix-reinforced powder metallurgy valve seat material possesses excellent high-temperature hardness and strength, strengthens the valve seat matrix, and achieves good bonding between the matrix and the hard material. It exhibits superior wear resistance and durability in the high-temperature, high-pressure, and lubrication-free environment of high-pressure engines.

[0094] It should be further noted that the tool steel powder and solid lubricant used in this invention can all be products of the prior art. For example, this invention does not have any special limitations on the type of solid lubricant; lubricants used in smelting alloys that are well known to those skilled in the art can be used. In this invention, the mass of the lubricant is preferably 0.2-1.8% of the total alloy raw materials, more preferably 0.8-1.2%, and most preferably 0.9-1.1%. These are all conventional additives used in smelting alloys, and the specific selection is based on the needs, which will not be elaborated here. Moreover, this invention requires that the proportion of alloy raw materials be sufficient to ensure that the proportion of each element in the mixture obtained after mixing the alloy raw materials conforms to the proportion of each element in the high-explosion-pressure engine valve seat alloy material. At the same time, this invention does not have any special limitations on the conventional processing steps used. For example, there are no special limitations on conventional cooling operations; cooling processes well known to those skilled in the art can be used.

[0095] The preferred embodiments of the present invention have been described in detail above, outlining the basic principles, main features, and advantages of the invention. However, those skilled in the art should understand that the embodiments of the present invention are not limited to the above-described embodiments. The embodiments and descriptions in the specification are merely preferred examples of the present invention and are not intended to limit the invention. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the embodiments of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. However, obvious changes or modifications derived therefrom are still within the protection scope of the embodiments of the present invention.

Claims

1. A high pressure engine valve seat insert alloy material, characterized by, The high-explosive engine valve seat alloy material, by mass percentage, consists of the following components: C: 0.9-1.5%, S: 0.2-1.0%, W: 7.0-8.3%, V: 9.4-11.1%, Co: 18.2-23.7%, Mo: 7.0-9.1%, Cr: 5.5-6.5%, Mn: 0.2-1.0%, Cu: 12.0-22.0%, Nb: 0.6-0.7%, with the balance being Fe and unavoidable impurities; The strengthening base powder components include W, Cr, V, and Fe, while the alloy powder components include Mo, Co, and Nb. The high-explosive-pressure engine valve seat alloy material is prepared using the following method: Using 55-65% reinforced tool steel powder as the reinforcing base powder, and adding 33-43% alloy powder, the alloy raw materials are mixed, pressed, sintered, copper infiltrated, cryogenically treated and heat-treated in sequence according to the composition ratio to obtain the high-explosive-pressure engine valve seat alloy material. The sintering temperature is 1110-1140℃; the cryogenic treatment is carried out after sintering and copper infiltration at -180℃ to -160℃; the heat treatment temperature is 500℃-600℃ and the time is 1-6 hours.

2. The high-explosive engine valve seat alloy material according to claim 1, characterized in that, The hardness of the high-explosive-pressure engine valve seat ring alloy material is 50-60 HRC, the density is 7.6-8.0 g / cm 3 , and the crushing strength is 800-950 MPa.

3. A method for preparing the high-explosive-pressure engine valve seat alloy material as described in claim 1 or 2, characterized in that, Includes the following steps: Using 55-65% reinforced tool steel powder as the reinforcing base powder, and adding 33-43% alloy powder, the alloy raw materials are mixed, pressed, sintered, copper infiltrated, cryogenically treated and heat-treated in sequence according to the composition ratio to obtain the high-explosive-pressure engine valve seat alloy material. The sintering temperature is 1110-1140℃; the cryogenic treatment is carried out after sintering and copper infiltration at -180℃ to -160℃; the heat treatment temperature is 500℃-600℃ and the time is 1-6 hours.

4. The method for preparing the high-explosive engine valve seat alloy material according to claim 3, characterized in that, In the preparation method of the high-explosive-pressure engine valve seat alloy material, the heat treatment temperature is 510℃-550℃ and the time is 2-5 hours.

5. The application of the high-explosive-pressure engine valve seat alloy material as described in claim 1 or 2 in the manufacture of engine parts.

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