Engine Materials and Their Preparation Methods, Engines and Vehicles Equipped with Such Engines

Abstract

The present application discloses an engine material, a preparation method thereof, an engine and a vehicle, belonging to the technical field of engine corrosion resistance. The preparation method of the engine material includes: providing a vanadium permeating agent, heating the vanadium permeating agent in a crucible to form a vanadium permeating salt solution; providing a stainless steel substrate, putting the stainless steel substrate into the vanadium permeating salt solution and keeping it warm, wherein the stainless steel substrate contains 2.5-3.0 wt.% of molybdenum; taking out the stainless steel substrate after heat preservation, performing tempering treatment and then cleaning to obtain the engine material. The present application solves the technical problem that the existing engine material has poor corrosion resistance to methanol.

Description

Technical Field

[0001] The present application relates to the technical field of engine corrosion resistance, and particularly relates to an engine material and a preparation method thereof, an engine and a vehicle thereof. Background Art

[0002] As an alternative fuel for vehicles, methanol has outstanding advantages such as low emissions, high octane number, and wide raw material sources, and is an ideal alternative energy source. However, during the application process of methanol, free radical reactions will occur, and the generated oxidation product formic acid is corrosive, which in turn causes methanol to have strong corrosiveness to engines. Conventional engine materials have poor corrosion resistance to methanol, which makes some components on the engine vulnerable to corrosion. Among them, the corrosion problem of the methanol injector valve seat is particularly prominent; the early corrosion of the methanol injector valve seat will cause the injector to drip, which in turn causes abnormal engine vibration, increased fuel consumption, deteriorated emissions, etc., making it difficult for the engine to work properly.

[0003] The above content is only used to assist in understanding the technical solution of the present application, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The main purpose of the present application is to provide an engine material and a preparation method thereof, an engine and a vehicle thereof, aiming to solve the technical problem of poor corrosion resistance of existing engine materials to methanol.

[0005] To achieve the above purpose, the present application provides a method for preparing an engine material, the method for preparing the engine material includes the following steps:

[0006] Provide a vanadiumizing agent, add the vanadiumizing agent into a crucible and heat it to form a vanadium salt solution;

[0007] Provide a stainless steel substrate, put the stainless steel substrate into the vanadium salt solution and keep it warm, wherein the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum;

[0008] Take out the heat-preserved stainless steel substrate, perform tempering treatment and then clean it to obtain the engine material.

[0009] Optionally, the stainless steel substrate is composed of the following components by mass percentage: carbon: 0.85 - 0.95%, chromium: 17 - 20%, molybdenum: 2.5 - 3.0%, manganese: 0.5 - 0.8%, nickel: 0.3 - 0.6%, phosphorus ≤ 0.03%, sulfur ≤ 0.03%, and the balance is iron and inevitable impurity elements, and the sum of each element is 100%.

[0010] Optionally, the vanadium permeating agent consists of components with the following mass percentage contents: borax: 75 - 81%, vanadium trioxide: 7 - 11%, vanadium pentoxide: 3 - 6%, sodium fluoride: 3 - 6%, and reducing agent: 4 - 8%.

[0011] Optionally, the reducing agent includes one or more of aluminum powder, silicon powder, and boron carbide.

[0012] Optionally, the temperature of the vanadium permeating salt solution is 900 - 920 °C.

[0013] Optionally, the heat preservation time of the stainless steel substrate in the vanadium permeating salt bath is 12 - 15 h.

[0014] Optionally, the temperature of the tempering treatment is 200 - 220 °C.

[0015] Optionally, the heat preservation time of the tempering treatment is 3 - 5 h.

[0016] Optionally, the surface hardness of the engine material is greater than 2250 HV 0.05 .

[0017] This application also provides an engine material, which is prepared by the above method; the engine material includes: a stainless steel substrate, the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum, and the surface of the stainless steel substrate has a vanadium carbide layer.

[0018] This application also provides an engine, which is an engine using the above material, and the engine is a fuel engine.

[0019] This application also provides a vehicle, which is a vehicle using the above material or the above engine.

[0020] The present application discloses a method for preparing engine materials. By providing a vanadium permeating agent, adding the vanadium permeating agent into a crucible and heating it to form a vanadium permeating salt solution; further providing a stainless steel substrate, putting the stainless steel substrate into the vanadium permeating salt solution and keeping it warm, wherein the stainless steel substrate contains 2.5-3.0 wt.% molybdenum; then taking out the stainless steel substrate after heat preservation, performing tempering treatment and then cleaning it to obtain the engine materials. By adding 2.5-3.0 wt.% molybdenum to the stainless steel substrate, a stable passivation film can be formed on the surface of the engine materials, thereby preventing the engine materials from being eroded by corrosive media and improving the corrosion resistance of the materials to methanol; further, by performing surface treatment on the stainless steel substrate with the vanadium permeating salt solution, a large amount of vanadium can penetrate into the surface of the stainless steel substrate; the vanadium element has a strong binding force with carbon itself and will form an extremely stable vanadium carbide layer structure, and then vanadium can be fused with molybdenum to form a dense and stable structure on the material surface, effectively inhibiting the entry of oxygen, which can not only achieve the purpose of inhibiting corrosion, but also improve the surface hardness of the engine materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic flow chart of the method for preparing engine materials according to the embodiment scheme of the present application;

[0022] Figure 2 It is a relationship diagram of the number of fuel injections and the leakage amount of an injector prepared from the engine materials of Embodiments 1-3 of the present application;

[0023] Figure 3 It is a relationship diagram of the number of fuel injections and the leakage amount of an injector prepared from the engine materials of Embodiment 1 and Comparative Example 1 of the present application;

[0024] Figure 4 It is a relationship diagram of the running time and the flow rate change rate of an engine prepared from the engine materials of Comparative Example 1 of the present application;

[0025] Figure 5 It is a relationship diagram of the running time and the flow rate change rate of an engine prepared from the engine materials of Embodiment 1 of the present application.

[0026] The realization, functional features and advantages of the purpose of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0028] In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0029] In the first aspect of the embodiments of this application, a method for preparing engine materials is provided. Referring to Figure 1 , the method for preparing engine materials includes:

[0030] Step S10, providing a vanadiumizing agent, adding the vanadiumizing agent into a crucible and heating it to form a vanadium salt solution;

[0031] Provide a vanadiumizing agent, add the vanadiumizing agent into a crucible and heat it to melt the vanadiumizing agent to form a vanadium salt solution.

[0032] Optionally, the vanadiumizing agent is composed of the following components by mass percentage: borax: 75 - 81%, vanadium trioxide: 7 - 11%, vanadium pentoxide: 3 - 6%, sodium fluoride: 3 - 6%, and reducing agent: 4 - 8%.

[0033] Preferably, the vanadiumizing agent is composed of the following components by mass percentage: borax: 76%, vanadium trioxide: 9%, vanadium pentoxide: 4%, sodium fluoride: 5%, and reducing agent: 6%.

[0034] Optionally, the reducing agent includes one or more of aluminum powder, silicon powder, and boron carbide.

[0035] Optionally, the temperature for heating the vanadiumizing agent in the crucible is 900 - 920 °C.

[0036] In this embodiment, sodium fluoride can act as an activator. By reacting with the reaction products on the surfaces of vanadium trioxide and vanadium pentoxide particles, it cleans the surfaces of the reducing agent particles, keeps the reducing agent highly active, makes the catalytic effect of vanadium and carbon more obvious, and further promotes the effective penetration of vanadium into the stainless steel matrix. While using both vanadium trioxide and vanadium pentoxide in the vanadiumizing agent can enhance the activity of vanadium atoms, have a better binding effect with the stainless steel matrix, and at the same time make the spatial organizational structure of the vanadium carbide layer more compact and the arrangement more regular, thereby effectively improving the surface hardness of the stainless steel substrate.

[0037] Step S20: Provide a stainless steel substrate, place the stainless steel substrate in the vanadium - impregnating salt solution and keep it warm. Among them, the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum;

[0038] Provide a stainless steel substrate, where the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum; then place the stainless steel substrate in the vanadium - impregnating salt solution and keep it warm for a preset time.

[0039] Optionally, the stainless steel substrate is composed of the following components by mass percentage: carbon: 0.85 - 0.95%, chromium: 17 - 20%, molybdenum: 2.5 - 3.0%, manganese: 0.5 - 0.8%, nickel: 0.3 - 0.6%, phosphorus ≤ 0.03%, sulfur ≤ 0.03%, and the balance is iron and unavoidable impurity elements, and the sum of all elements is 100%.

[0040] In this embodiment, the carbon content of the stainless steel substrate is 0.85 - 0.95%, which can not only meet the hardness requirements of the engine material but also minimize the corrosion tendency of the engine material; the chromium content of the stainless steel substrate is 17 - 20%, which maximally improves the corrosion resistance of the engine material on the basis of controlling the cost of the engine material; the molybdenum content of the stainless steel substrate is 2.5 - 3.0%, which can form a stable passive film through molybdenum elements, prevent the engine material from being eroded by corrosive media, improve the corrosion resistance of the material to methanol, and to a certain extent improve the hardness and wear resistance of the engine material.

[0041] Optionally, the temperature of the vanadium - impregnating salt solution is 900 - 920 °C, so that the stainless steel substrate undergoes salt - bath vanadium impregnation at a temperature of 900 - 920 °C.

[0042] Optionally, the holding time of the stainless steel substrate in the vanadium - impregnating salt bath is 12 - 15 h.

[0043] In this embodiment, the holding time of the stainless steel substrate in the vanadium - impregnating salt bath is at least 12 h, which can effectively promote the fusion of vanadium and molybdenum on the surface of the stainless steel substrate.

[0044] In a feasible implementation manner, before the step of providing the stainless steel substrate in step S20, it further includes:

[0045] Step S21: Configure raw materials according to the components and mass percentages of the stainless steel substrate, and melt the raw materials into molten steel;

[0046] Prepare raw materials according to the composition of the stainless steel substrate and the mass percentage content of each component, including: carbon: 0.85 - 0.95%, chromium: 17 - 20%, molybdenum: 2.5 - 3.0%, manganese: 0.5 - 0.8%, nickel: 0.3 - 0.6%, phosphorus ≤ 0.03%, sulfur ≤ 0.03%, with the balance being iron and inevitable impurity elements, and the sum of all elements being 100%; then melt it into molten steel.

[0047] Step S22: Vacuum smelt, pour, and roll the molten steel into raw steel, and process the raw steel into shape to obtain the stainless steel substrate.

[0048] Vacuum smelt, pour, and roll the molten steel into raw steel, and according to requirements, process the raw steel into shape to obtain a stainless steel substrate; the stainless steel substrate can be processed into a suitable shape according to application requirements. For example, it can be processed into an injector valve seat in a fuel engine to obtain an injector valve seat substrate. Then, put the injector valve seat substrate into the vanadium - permeating salt solution and keep it warm. After taking out the stainless steel substrate after heat preservation, perform tempering treatment and then cleaning to obtain the injector valve seat material.

[0049] Step S30: Take out the stainless steel substrate after heat preservation, perform tempering treatment and then cleaning to obtain the engine material.

[0050] Take out the stainless steel substrate after heat preservation, and perform cleaning with acid - containing boiling water after tempering treatment to remove the residual salts that have not fallen off to obtain the engine material; the acid - containing boiling water can be a boiling 5% sulfuric acid solution added with a corrosion inhibitor.

[0051] Optionally, the temperature of the tempering treatment is 200 - 220 °C.

[0052] Optionally, the heat preservation time of the tempering treatment is 3 - 5 h.

[0053] Optionally, the surface hardness of the engine material is greater than 2250 HV 0.05 while the surface hardness of the conventional engine material 9Cr18 (high - carbon high - chromium martensitic stainless steel) is about 60 HRC.

[0054] In this embodiment, by providing a vanadiumizing agent, adding the vanadiumizing agent into a crucible and heating it to form a vanadiumizing salt solution; furthermore, providing a stainless steel substrate, putting the stainless steel substrate into the vanadiumizing salt solution and keeping it warm, wherein the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum; then taking out the stainless steel substrate after heat preservation, performing tempering treatment and then cleaning it to obtain an engine material. By adding 2.5 - 3.0 wt.% molybdenum to the stainless steel substrate, a stable passivation film can be formed on the surface of the engine material, thereby preventing the engine material from being eroded by corrosive media and enhancing the corrosion resistance of the material to methanol; furthermore, by performing surface treatment on the stainless steel substrate with the vanadiumizing salt solution, a large amount of vanadium can penetrate into the surface of the stainless steel substrate; the vanadium element has a strong binding force with carbon itself and will form an extremely stable vanadium carbide layer structure. Furthermore, vanadium can be fused with molybdenum to form a dense and stable structure on the material surface, effectively inhibiting the entry of oxygen, which can not only achieve the purpose of inhibiting corrosion but also improve the surface hardness of the engine material.

[0055] To enable those skilled in the art to clearly understand the details and operations of the above embodiments of the present application, and to significantly reflect the progressive performance of the embodiments of the present application, the following uses multiple embodiments to illustrate the above technical solutions.

[0056] Example 1

[0057] Provide a vanadiumizing agent, the vanadiumizing agent is composed of the following components by mass percentage: borax: 76%, vanadium trioxide: 9%, vanadium pentoxide: 4%, sodium fluoride: 5% and boron carbide: 6%; add the vanadiumizing agent into a crucible and heat it to 910 °C to form a vanadiumizing salt solution;

[0058] Provide a stainless steel substrate, the stainless steel substrate is composed of the following components by mass percentage: carbon: 0.91%, chromium: 18.2%, molybdenum: 2.6%, manganese: 0.6%, nickel: 0.5%, phosphorus: 0.01%, sulfur: 0.01%, and the balance is iron and inevitable impurity elements, and the sum of each element is 100%; put the stainless steel substrate into the vanadiumizing salt solution and keep it warm at 910 °C for 12 h;

[0059] Take out the stainless steel substrate after heat preservation, perform tempering treatment at 210 °C for a heat preservation duration of 3 h, and then perform cleaning to obtain an engine material; furthermore, use the engine material to prepare an injector valve seat.

[0060] Example 2

[0061] Provide a vanadiumizing agent, the vanadiumizing agent is composed of the following components by mass percentage: borax: 80%, vanadium trioxide: 7%, vanadium pentoxide: 4%, sodium fluoride: 5% and boron carbide: 4%; add the vanadiumizing agent into a crucible and heat it to 920 °C to form a vanadiumizing salt solution;

[0062] Provide a stainless steel substrate, the stainless steel substrate is composed of the following components by mass percentage: carbon: 0.95%, chromium: 20%, molybdenum: 3.0%, manganese: 0.5%, nickel: 0.6%, phosphorus: 0.02%, sulfur: 0.02%, the balance is iron and unavoidable impurity elements, and the sum of each element is 100%; put the stainless steel substrate into the vanadium infiltration salt solution and keep it warm at 920 °C for 15 h;

[0063] Take out the heat-insulated stainless steel substrate, perform tempering treatment at 220 °C for 5 h, and then perform cleaning to obtain engine materials; then use the engine materials to prepare injector valve seats.

[0064] Example 3

[0065] Provide a vanadium infiltrant, the vanadium infiltrant is composed of the following components by mass percentage: borax: 75%, vanadium trioxide: 11%, vanadium pentoxide: 3%, sodium fluoride: 5% and boron carbide: 6%; add the vanadium infiltrant to a crucible and heat it to 900 °C to form a vanadium infiltration salt solution;

[0066] Provide a stainless steel substrate, the stainless steel substrate is composed of the following components by mass percentage: carbon: 0.85%, chromium: 18%, molybdenum: 2.5%, manganese: 0.5%, nickel: 0.6%, phosphorus: 0.03%, sulfur: 0.03%, the balance is iron and unavoidable impurity elements, and the sum of each element is 100%; put the stainless steel substrate into the vanadium infiltration salt solution and keep it warm at 900 °C for 12 h;

[0067] Take out the heat-insulated stainless steel substrate, perform tempering treatment at 200 °C for 5 h, and then perform cleaning to obtain engine materials; then use the engine materials to prepare injector valve seats.

[0068] Comparative Example 1

[0069] Use commercial 9Cr18 (high-carbon high-chromium martensitic stainless steel) as engine materials to prepare injector valve seats.

[0070] Furthermore, in order to verify the progressiveness of the embodiments of the present application, the following performance tests were carried out on each embodiment and comparative example:

[0071] 1. Injector monomer test:

[0072] 1.1 Use the injector valve seats prepared in Application Examples 1-3 to prepare injectors. Among them, Application Example 1 corresponds to injector number 1, Application Example 2 corresponds to injector number 2, and Application Example 3 corresponds to injector number 3. Conduct 600 million injector injection tests under the working conditions of injector injection frequency: 200 Hz, injector opening pulse width: 2.5 ms, injector injection pressure: 0.4 MPa, and test medium: pure methanol (without additives). Take 0.3 mL / min as the fuel injection volume limit and record the fuel injection volume. The results are shown in Figure 2 as shown.

[0073] Refer to Figure 2 It can be seen that for the injectors prepared with the injector valve seats prepared in Application Examples 1-3, during the 600 million injection tests, the leakage rates are all lower than 0.25 mL / min, meeting the standard that the injector leakage rate is within 0.3 mL / min, and all have good corrosion resistance.

[0074] 1.2 Use the injector valve seats prepared in Application Example 1 and Comparative Example 1 to prepare 8 injectors respectively. Among them, Comparative Example 1 corresponds to injector numbers 1-8, and Application Example 1 corresponds to injector numbers 9-16. Conduct 600 million injector injection tests under the working conditions of injector injection frequency: 200 Hz, injector opening pulse width: 2.5 ms, injector injection pressure: 0.4 MPa, and test medium: pure methanol (without additives), and record the fuel injection volume. The results are shown in Figure 3 as shown.

[0075] Refer to Figure 3 It can be seen that for the injectors prepared with the material in Comparative Example 1, during the 200 millionth fuel injection test, the leakage rate exceeded 3 mL / min, and the fuel injection test was unqualified. For the injectors prepared with the material in Application Example 1, during the 600 million injection tests, the leakage rates are all lower than 0.3 mL / min, meeting the standard that the injector leakage rate is within 0.3 mL / min, and having good corrosion resistance.

[0076] 2. Bench durability test:

[0077] 2.1 Use the injector valve seats prepared in Comparative Example 1 to prepare injectors, including the first to fourth injectors, and install them on a fuel engine respectively to conduct an 800-hour bench durability test. The results are as Figure 4 shown.

[0078] Refer to Figure 4 It can be seen that at the 200th hour, the flow rate change rates of the first to fourth injectors all exceeded 6%, and all the injectors leaked and failed.

[0079] 2.2 Fabricate fuel injectors using the injector valve seats prepared in Application Example 1, including the fifth to eighth fuel injectors, and install them on a fuel engine respectively for 800 hours of bench durability testing. The results are as Figure 5 shown.

[0080] Refer to Figure 5 It can be seen that the flow rate change rates of the first to fourth fuel injectors are all lower than 4% within 800 hours, meeting the test requirements and having good corrosion resistance.

[0081] 3. Surface hardness test:

[0082] Conduct surface hardness tests on the engine materials prepared in Examples 1 - 3. The results are shown in Table 1 below:

[0083] Table 1

[0084] Test group <![CDATA[Surface hardness / HV 0.05 > Example 1 2253 Example 2 2251 Example 3 2252

[0085] According to the surface hardness test results in Table 1, it can be seen that the surface hardness of the engine materials prepared in Examples 1 - 3 of this application is greater than 2250 HV 0.05 , having a relatively high surface hardness. This is achieved by surface - treating the stainless - steel matrix with a vanadium - containing salt solution, enabling a large amount of vanadium to penetrate into the surface of the stainless - steel matrix. The vanadium element has a strong binding force with carbon and will form an extremely stable vanadium carbide layer structure. Furthermore, vanadium can fuse with molybdenum to form a dense and stable structure on the material surface, effectively inhibiting the entry of oxygen, which not only achieves the purpose of corrosion inhibition but also improves the surface hardness of the engine material.

[0086] The above are only the preferred embodiments of this application, and do not limit the patent scope of this application. For those skilled in the art, various changes and modifications can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the patent protection scope of this application.

Claims

1. A method for preparing an engine material, characterized in that, It includes the following steps: Provide a vanadium permeating agent, wherein the vanadium permeating agent is composed of components with the following mass percentage contents: borax: 75 - 81%, vanadium trioxide: 7 - 11%, vanadium pentoxide: 3 - 6%, sodium fluoride: 3 - 6%, and a reducing agent: 4 - 8%; Add the vanadium permeating agent into a crucible and heat it to form a vanadium permeating salt solution; Provide a stainless steel substrate, put the stainless steel substrate into the vanadium permeating salt solution and keep it warm, wherein the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum; Take out the heat - preserved stainless steel substrate, perform tempering treatment and then clean it to obtain an engine material.

2. The method for preparing the engine material according to claim 1, wherein The stainless steel substrate is composed of components with the following mass percentage contents: carbon: 0.85 - 0.95%, chromium: 17 - 20%, molybdenum: 2.5 - 3.0%, manganese: 0.5 - 0.8%, nickel: 0.3 - 0.6%, phosphorus ≤ 0.03%, sulfur ≤ 0.03%, and the balance is iron and inevitable impurity elements, and the sum of all elements is 100%.

3. The method for preparing the engine material according to claim 1, wherein The reducing agent includes one or more of aluminum powder, silicon powder and boron carbide.

4. The method for preparing the engine material according to claim 1, wherein The temperature of the vanadium permeating salt solution is 900 - 920 °C.

5. The method for preparing engine materials according to claim 1, wherein, The heat - preservation time of the stainless steel substrate in the vanadium permeating salt solution is 12 - 15 h.

6. The method for preparing engine materials according to claim 1, characterized in that, The temperature of the tempering treatment is 200 - 220 °C.

7. The method for preparing engine materials according to claim 1, characterized in that, The heat - preservation time of the tempering treatment is 3 - 5 h.

8. The method for preparing engine materials according to claim 1, characterized in that The surface hardness of the engine material is greater than 2250 HV 0.05 .

9. An engine material, characterized in that, The engine material is obtained by the method according to any one of claims 1 - 8; the engine material includes: a stainless steel substrate, the stainless steel substrate contains 2.5 - 3.0 wt.% molybdenum, and the surface of the stainless steel substrate has a vanadium carbide layer.

10. An engine using the material as described in claim 9, characterized in that, The engine is a fuel engine.

11. A vehicle, characterized in that, Use the material according to claim 9 or the engine according to claim 10.

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