Magnesium alloy hot forging forming lubricant and preparation method thereof

Abstract

The invention discloses a magnesium alloy hot forging forming lubricant and a preparation method thereof, and the lubricant comprises the following components by mass: 2-15% of a film forming agent; 5-20% of an alkali metal salt of carboxylic acid; 0.5-2% of an emulsifying dispersant; 1-5% of a solid lubricant; and the balance water. According to the magnesium alloy hot forging forming lubricant, boron nitride, talcum powder and the like are combined with the acrylic resin emulsion, a gradient lubricating film is formed at the high temperature, a synergistic lubricating system is formed, the demolding effect is guaranteed, and the problem of environmental pollution of a traditional graphite lubricant is avoided; meanwhile, through the synergistic effect of the polyvinylpyrrolidone, the isobutylene maleate sodium salt and the isophthalic acid disodium salt, the film forming uniformity of the lubricant on the surface of a 380-DEG C mold is improved, and the spraying frequency can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricants, and in particular to a magnesium alloy hot forging lubricant and a preparation method thereof. Background Art

[0002] Magnesium alloys are widely used in aerospace, automotive manufacturing, consumer electronics and other fields due to their light weight and high specific strength. Magnesium alloy products are usually made by hot forging. During the hot forging process, due to the high temperature conditions of hot die forging, the metal may experience uneven flow rate and uneven pressure in the cavity, which may lead to abnormal die sticking in production, such as die roughness and material sticking to the die. Therefore, it is necessary to spray a release agent on the die before forging the product to isolate the metal and the die. At the same time, the lubricating components in the release agent adhere to the die to play a lubricating role, which helps metal forming. However, there are still some technical difficulties in the hot forging process of magnesium alloys:

[0003] (1) High temperature die sticking problem: The hot forging temperature of magnesium alloy is relatively high, and the material temperature is usually above 380°C. Traditional mold release agents are prone to decomposition and failure, resulting in die sticking and surface scratches on forgings.

[0004] (2) Insufficient lubrication performance: The lubricating film of conventional water-based release agents breaks down at high temperatures, causing a sharp increase in the friction coefficient and accelerating mold wear;

[0005] To solve these technical difficulties, the existing technology usually uses graphite-based release agents to meet the workpiece processing precision requirements. However, organic solvents and graphite powder will produce a large amount of oil smoke and graphite at high temperatures, polluting the environment and endangering operational safety. The existing technology also uses release agents based on oleic acid and diamond powder. This release agent relies on an oil-based system, is easily oxidized at high temperatures, and is not suitable for magnesium alloys. There is also a water-based release agent based on paraffin, stearic acid, vegetable oil, etc., formed by an emulsifier. This water-based release agent is only suitable for forging conditions with a temperature of ≤250°C and cannot meet the high temperature requirements of hot forging of magnesium alloys. Summary of the Invention

[0006] The purpose of the present invention is to address the shortcomings of the existing technology and provide a magnesium alloy hot forging lubricant and a preparation method thereof. The lubricant can achieve efficient demolding under extreme conditions of a magnesium alloy hot forging die temperature of 380°C and a material temperature of 400°C by optimizing the synergistic effect of a film-forming agent, a high-temperature lubricant and a heat-resistant resin, thereby significantly improving the surface quality of the forging and the service life of the die.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In one aspect, a magnesium alloy hot forging lubricant is provided, comprising the following components by mass percentage:

[0009]

[0010]

[0011] As a preferred solution for magnesium alloy hot forging lubricant, the film-forming agent is selected from one or more of polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylamide, isobutylene maleic acid copolymer, isobutylene maleic acid sodium salt, and hydrophilic resin, which can form a dense film layer at high temperature and enhance the adhesion of the lubricant.

[0012] As a preferred solution for the lubricant for hot forging of magnesium alloys, the hydrophilic resin includes one or more of acrylic resin emulsion, phenylpropionic acid resin emulsion, and polyester resin emulsion.

[0013] As a preferred solution for the hot forging lubricant for magnesium alloys, the alkali metal salt of the carboxylic acid is selected from one or more of disodium isophthalate, disodium phthalate, disodium terephthalate, and disodium adipate.

[0014] As a preferred solution for the lubricant for hot forging of magnesium alloys, the emulsifying dispersant is selected from one or more of fatty alcohol polyoxyethylene ether, sodium dodecyl diphenyl ether disulfonate, and Span 80.

[0015] As a preferred solution for the lubricant for hot forging of magnesium alloys, the fixed lubricant is selected from one or more of boron nitride, hydrophilic silica, oleophilic silica, titanium oxide, mica powder, talc powder, and glass powder.

[0016] In another aspect, a method for preparing a magnesium alloy hot forging lubricant is provided, comprising the following steps:

[0017] S1, reacting sodium hydroxide or sodium carbonate with carboxylic acid and water in a certain reaction ratio to obtain an alkali metal salt solution of the carboxylic acid;

[0018] S2. Add a film-forming agent to part of the water, stir at high speed at 1000-1500 rpm for 10 minutes, then add the alkali metal salt solution of carboxylic acid, and continue stirring for 10 minutes;

[0019] S3, adding an emulsifying dispersant to the solution in step S2, stirring for 10 minutes, then adding the remaining water and film-forming agent, and continuing stirring for 10 minutes;

[0020] S4. Add a solid lubricant to the solution in step S3, and high-speed shear for 20 minutes at 1000-1500 rpm to obtain a stable lubricant suspension.

[0021] Beneficial effects of the present invention:

[0022] (1) The magnesium alloy hot forging lubricant of the present invention combines boron nitride, talcum powder, etc. with acrylic resin emulsion to form a gradient lubricating film at high temperature, constituting a synergistic lubrication system, which not only ensures the demoulding effect but also avoids the environmental pollution problem of traditional graphite lubricants.

[0023] (2) The magnesium alloy hot forging lubricant of the present invention is water-based, replacing the traditional oil-based / salt-based system, has no heavy metal pollution, and is more environmentally friendly.

[0024] (3) The magnesium alloy hot forging lubricant of the present invention improves the film formation uniformity of the lubricant on the mold surface at 380°C through the synergistic effect of polyvinyl pyrrolidone, sodium isobutylene maleate and disodium isophthalate, which can effectively reduce the spraying frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0026] Figure 1 This is a schematic diagram of the effect of the magnesium alloy hot forging lubricant according to Example 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the effect of the magnesium alloy hot forging lubricant according to Example 2 of the present invention.

[0028] Figure 3 It is a schematic diagram of the effect of the magnesium alloy hot forging lubricant of Comparative Example 1 of the present invention.

[0029] Figure 4 This is a schematic diagram of the effect of the magnesium alloy hot forging lubricant in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0031] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0032] Example 1:

[0033] The magnesium alloy hot forging lubricant of this embodiment is obtained by reacting the following raw materials in percentage by mass:

[0034]

[0035] When preparing the magnesium alloy hot forging lubricant, the raw materials are added according to the above-mentioned addition amounts, which includes the following steps:

[0036] Sodium hydroxide or sodium carbonate is reacted with carboxylic acid and water in a certain reaction ratio to prepare disodium isophthalate solution;

[0037] Add polyvinyl pyrrolidone to part of the water, stir at high speed at 1000-1500 rpm for 10 minutes, then add disodium isophthalate solution and continue stirring for 10 minutes;

[0038] Add fatty alcohol polyoxyethylene ether to the solution and stir for 10 minutes, then add the remaining water and acrylic resin emulsion and continue stirring for 10 minutes;

[0039] Boron nitride and talc were added to the solution, and high-speed shearing was performed at 1000-1500 rpm for 20 minutes to obtain a stable lubricant suspension.

[0040] Example 2:

[0041] The magnesium alloy hot forging lubricant of this embodiment is obtained by reacting the following raw materials in percentage by mass:

[0042]

[0043] When preparing the magnesium alloy hot forging lubricant, the raw materials are added according to the above-mentioned addition amounts, which includes the following steps:

[0044] Sodium hydroxide or sodium carbonate is reacted with carboxylic acid and water in a certain reaction ratio to prepare disodium isophthalate solution;

[0045] Sodium hydroxide, isobutylene maleic acid copolymer and water are heated to 80-90° C. according to a certain reaction ratio for reaction, and stirred at a high speed of 1000-1500 rpm for 60 minutes to obtain an isobutylene disodium maleate solution;

[0046] Add disodium isophthalate solution and disodium isobutylene maleate solution to the remaining water and continue stirring for 10 minutes;

[0047] Add fatty alcohol polyoxyethylene ether to the solution and stir for 10 minutes;

[0048] Boron nitride was added to the solution, and high-speed shearing was performed at 1000-1500 rpm for 20 minutes to obtain a stable lubricant suspension.

[0049] Comparative Example 1:

[0050] The magnesium alloy hot forging lubricant of this embodiment is obtained by reacting the following raw materials in percentage by mass:

[0051]

[0052] When preparing the magnesium alloy hot forging lubricant, the raw materials are added according to the above-mentioned addition amounts, which includes the following steps:

[0053] Sodium hydroxide, isobutylene maleic acid copolymer and water are heated to 80-90° C. according to a certain reaction ratio for reaction, and stirred at a high speed of 1000-1500 rpm for 60 minutes to prepare an isobutylene disodium maleate solution;

[0054] Add the disodium isobutylene maleate solution to the remaining water and stir at 1000-1500 rpm for 10 minutes; then add the fatty alcohol polyoxyethylene ether and stir for 10 minutes to obtain a stable lubricant solution.

[0055] Comparative Example 2:

[0056] The magnesium alloy hot forging lubricant of this embodiment is obtained by reacting the following raw materials in percentage by mass:

[0057]

[0058] When preparing the magnesium alloy hot forging lubricant, the raw materials are added according to the above-mentioned addition amounts, which includes the following steps:

[0059] Sodium hydroxide, isobutylene maleic acid copolymer and water are heated to 80-90° C. according to a certain reaction ratio for reaction, and stirred at a high speed of 1000-1500 rpm for 60 minutes to prepare an isobutylene disodium maleate solution;

[0060] Sodium hydroxide is reacted with isophthalic acid, adipic acid and water in a certain reaction ratio and stirred for 20 minutes to prepare disodium isophthalate and disodium adipate solutions;

[0061] Disodium isobutylene maleate solution, disodium isophthalate, and disodium adipate solution were added to the remaining water, and the mixture was stirred at a high speed of 1000-1500 rpm for 20 minutes to obtain a stable lubricant solution.

[0062] Verification experiment:

[0063] To better demonstrate the beneficial effects of this magnesium alloy hot forging lubricant, the following series of tests were conducted.

[0064] Test items: Examples 1-2 and Comparative Examples 1-2 were respectively mixed with water at a ratio of 1:6 to prepare dilutions of the same concentration, and sprayed on a 380°C mold steel plate to observe the uniformity and temperature resistance of the lubricant film formed by each group.

[0065] Uniformity: Evaluates whether the sample can effectively adhere to the steel plate and form a film under high temperature conditions.

[0066] Temperature resistance: Evaluate whether the film-forming properties of the sample change from spraying on the mold to demolding due to insufficient temperature resistance.

[0067] Experimental conditions: The spraying pressure, spraying height, and spraying amount of each group of experiments were kept consistent. The lubricant spraying amount was 50g, the spraying time was 30s, the mold steel plate temperature was 380℃, and the temperature was maintained for 30s after spraying, for a total of 1 minute. The film formation area and color changes of each group of lubricants on the mold surface at a continuous constant temperature were observed to determine the film uniformity and temperature resistance of the samples.

[0068] Evaluation criteria:

[0069] The uniformity is ranked from best to worst as A, B, and C, with A being uniform, B being partially uniform, and C being uneven.

[0070] The temperature resistance is arranged from best to worst as A, B, C, and D. Grade A is white, grade B is slightly yellow, grade C is dark yellow, and grade D is brown to black.

[0071] Table 1 Uniformity and temperature resistance test of magnesium alloy hot forging lubricant

[0072] Experimental Project Example 1 Example 2 Comparative Example 1 Comparative Example 2 Film uniformity A-level A-level C-level Class B Film forming temperature resistance Class B A-level C-level C-level

[0073] The test results are shown in Table 1 and Figures 1 to 4 As shown, by comparing Example 1 and Example 2, it can be found that compared with Example 1 prepared by adding two film-forming agents, polyvinyl pyrrolidone and acrylic resin emulsion, and Example 2 prepared by adding isobutylene sodium maleate as a film-forming agent, both have very excellent film uniformity effects and can be applied to the hot forging process of magnesium alloys; at the same time, the temperature resistance of the film formed in Example 2 is better than that in Example 1. This is mainly because the combination of boron nitride and isobutylene sodium maleate can form a synergistic lubrication system, forming a gradient lubrication film at high temperature, which not only ensures the demolding effect, but also avoids the environmental pollution problem of traditional graphite lubricants.

[0074] By comparing Example 2 and Comparative Example 1, it can be found that compared with Comparative Example 1 without adding boron nitride, Example 2 with the addition of boron nitride has better lubricant film uniformity and temperature resistance than Comparative Example 1, which indicates that boron nitride helps to improve the demolding effect of the lubricant in the hot forging process.

[0075] By comparing Comparative Example 1 and Comparative Example 2, it can be found that compared with Comparative Example 1 in which no disodium isophthalate and disodium adipate are added, the lubricant film uniformity of Comparative Example 2 is slightly better than that of Comparative Example 1, indicating that disodium isophthalate and disodium adipate have a certain influence on the film uniformity of the magnesium alloy hot forging lubricant. This is mainly due to the synergistic effect of sodium isobutylene maleate with disodium isophthalate and disodium adipate, which improves the film uniformity of the lubricant on the mold surface at 380°C.

[0076] The above examples are intended only to illustrate the detailed methods of the present invention. The present invention is not limited to the above detailed methods, nor does it mean that the present invention must rely on the above detailed methods to be implemented. Those skilled in the art will understand that any improvements to the present invention, equivalent replacements of raw materials for the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims

1. A magnesium alloy hot forging lubricant, characterized in that: Calculated by mass percentage, it includes the following components:

2. The magnesium alloy hot forging lubricant according to claim 1, characterized in that: The film-forming agent is selected from one or more of polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylamide, isobutylene maleic acid copolymer, isobutylene maleic acid sodium salt, and hydrophilic resin.

3. The magnesium alloy hot forging lubricant according to claim 2, characterized in that: The hydrophilic resin includes one or more of acrylic resin emulsion, phenylpropionic acid resin emulsion, and polyester resin emulsion.

4. The magnesium alloy hot forging lubricant according to claim 1, characterized in that: The alkali metal salt of carboxylic acid is selected from one or more of disodium isophthalate, disodium phthalate, disodium terephthalate, and disodium adipate.

5. The magnesium alloy hot forging lubricant according to claim 1, characterized in that: The emulsifying dispersant is selected from one or more of fatty alcohol polyoxyethylene ether, sodium dodecyl diphenyl ether disulfonate, and Span 80.

6. The magnesium alloy hot forging lubricant according to claim 1, characterized in that: The fixed lubricant is selected from one or more of boron nitride, hydrophilic silica, oleophilic silica, titanium oxide, mica powder, talc powder, and glass powder.

7. A method for preparing a magnesium alloy hot forging lubricant, characterized in that: The following steps are involved: S1, reacting sodium hydroxide or sodium carbonate with carboxylic acid and water in a certain reaction ratio to obtain an alkali metal salt solution of the carboxylic acid; S2. Add a film-forming agent to part of the water, stir at high speed at 1000-1500 rpm for 10 minutes, then add the alkali metal salt solution of carboxylic acid, and continue stirring for 10 minutes; S3, adding an emulsifying dispersant to the solution in step S2, stirring for 10 minutes, then adding the remaining water and film-forming agent, and continuing stirring for 10 minutes; S4. Add a solid lubricant to the solution in step S3, and high-speed shear for 20 minutes at 1000-1500 rpm to obtain a stable lubricant suspension.

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