Grinding fluid for ferrous metal working and method for preparing the same

Abstract

The application provides a grinding fluid for ferrous metal processing and a preparation method thereof. The grinding fluid comprises the following raw materials in parts by weight: 60-90 parts of deionized water, 15-25 parts of a lubricating component, 10-20 parts of an anti-rust component, 5-10 parts of a sedimentation component, 4-8 parts of a surfactant component, 3-5 parts of an antifoaming component, 3-5 parts of an antibacterial component, and 1-3 parts of a pH adjusting component. The sedimentation component is composed of potassium ferrocyanide, cyclodextrin and modified chitosan in a mass ratio of (1-3):(1-3):(2-4), and the anti-rust component is composed of pyridine formaldehyde Schiff base, sodium thiosulfate and borate ester in a mass-volume ratio g / mL of (1-3):(1-2):(2-4). The potassium ferrocyanide, cyclodextrin and modified chitosan in the sedimentation component synergistically form a complex sedimentation system, which acts on the metal powder particles in the grinding fluid to make them quickly settle and remain at the bottom. The pyridine formaldehyde Schiff base, sodium thiosulfate and borate ester in the anti-rust component synergistically form a multi-layer and multi-dimensional anti-rust protection system on the metal surface.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of grinding fluid, in particular to a grinding fluid for ferrous metal processing and a preparation method thereof. BACKGROUND

[0002] Grinding processing has the characteristics of high cutting speed, high machining precision and small surface roughness, and a large amount of heat is generated during grinding process, which can be as high as 1000℃, which requires a large amount of grinding fluid for cooling. Grinding fluid can effectively reduce friction and heat accumulation through lubrication and cooling effect, thereby improving material removal rate and maintaining workpiece surface quality. Especially for the processing of ferrous metals, since ferrous metals have relatively active chemical properties, they are easy to react with oxygen, water and other substances in the environment to form rust, so how to improve the rust resistance is a major difficulty that needs to be solved for grinding fluid for ferrous metal processing. In addition, the metal powder generated during the grinding process is relatively fine and easy to suspend in the grinding fluid, which leads to a decrease in the cleanliness of the grinding fluid and also hinders the heat conduction between the grinding fluid and the workpiece, thereby reducing the cooling effect of the grinding fluid. And the metal powder may be embedded in the lubricating film between the grinding fluid and the workpiece, which destroys the integrity of the lubricating film and reduces its lubricating effect. Therefore, developing a grinding fluid with better sedimentation performance is also a difficult problem that needs to be solved. SUMMARY

[0003] In view of this, the present application provides a grinding fluid for ferrous metal processing and a preparation method thereof to solve the above problems.

[0004] The technical scheme of the present application is as follows:

[0005] A grinding fluid for ferrous metal processing, comprising the following raw materials by weight: 60-90 parts of deionized water, 15-25 parts of a lubricating component, 10-20 parts of an anti-rust component, 5-10 parts of a sedimentation component, 4-8 parts of a surfactant component, 3-5 parts of an antifoaming component, 3-5 parts of an antibacterial component, and 1-3 parts of a pH adjusting component. The sedimentation component is composed of potassium ferrocyanide, cyclodextrin and modified chitosan in a mass ratio of (1-3):(1-3):(2-4), and the anti-rust component is composed of pyridine formaldehyde Schiff base, sodium thiosulfate and borate ester in a mass-volume ratio g / mL of (1-3):(1-2):(2-4).

[0006] Further, the modified chitosan is prepared by the following method: chitosan is dissolved in pure water, and stirred at 50-60℃ until completely dissolved to form a chitosan solution. The mass / volume ratio g / mL of chitosan to pure water is 1:(20-40). Glutaraldehyde is added to the above chitosan solution, and the pH value is adjusted to 4.5-5.5 to obtain reaction liquid I, which is stirred at 40-50℃ for 2-4h to obtain cross-linked chitosan. The volume ratio of chitosan solution to glutaraldehyde is 10.0:(2.5-3.5). After the reaction is completed, the reaction liquid I is poured into a Buchner funnel, and filtered under a vacuum degree of 0.05-0.10MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2-3 times, and then placed in a drying machine for drying at 60-80℃ for 6-10h. After the drying is completed, the filter cake is ground in a mortar to obtain cross-linked chitosan powder. The cross-linked chitosan powder is dissolved in pure water, and stirred at 50-60℃ until completely dissolved to form a cross-linked chitosan solution. The mass / volume ratio g / mL of cross-linked chitosan powder to pure water is 1:(30-60). Succinic anhydride is added to the above cross-linked chitosan solution, and the pH value is adjusted to 7.0-8.0 to obtain reaction liquid II, which is stirred at room temperature for 4-6h. After the reaction is completed, the reaction liquid II is poured into a Buchner funnel, and filtered under a vacuum degree of 0.05-0.10MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2-3 times, and then placed in a drying machine for drying at 60-70℃ for 8-12h. After the drying is completed, the filter cake is ground in a mortar to obtain modified chitosan.

[0007] Further, the pyridine formaldehyde Schiff base is prepared by the following method: 2-pyridine formaldehyde is dissolved in ethanol to obtain a pyridine formaldehyde solution. The molar volume ratio mol / L of 2-pyridine formaldehyde to ethanol is 1:(4-6). Ethylenediamine is dissolved in ethanol to obtain an ethylenediamine solution. The molar volume ratio mol / L of ethylenediamine to ethanol is 1:(4-6). The pyridine formaldehyde solution is slowly added to the ethylenediamine solution at room temperature to obtain reaction liquid III, which is stirred for 2-4h. After the reaction is completed, the reaction liquid III is poured into a Buchner funnel, and filtered under a vacuum degree of 0.05-0.10MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with ethanol for 2-3 times, recrystallized, dried at 55-65℃ for 4-6h, and then ground in a mortar to obtain a pyridine formaldehyde Schiff base.

[0008] Further, the lubricating component is one or a combination of polyethylene glycol, polypropylene glycol, fatty acid amide, phosphate ester, triethanolamine, and monoethanolamine.

[0009] Further, the pH adjusting component is one of sodium hydroxide, potassium hydroxide, and sodium carbonate.

[0010] Further, the surface active component is one or a combination of alkyl sulfonate, alkyl benzene sulfonate, polyoxyethylene fatty acid ester, alkyl phenol polyoxyethylene ether, alkyl betaine, sulfobetaine, saponin.

[0011] Further, the defoaming component is one or a combination of polysiloxane defoamer, polyether defoamer, higher alcohol defoamer, polyurea defoamer.

[0012] Further, the antibacterial component is one or a combination of polyhexamethylene biguanide hydrochloride, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride, isothiazolinone.

[0013] Further, a preparation method of a grinding fluid for ferrous metal processing, comprising the following steps:

[0014] S1, adding a lubricating component and a rust-proof component to deionized water, and ultrasonic stirring for 20-30 min under the condition of ultrasonic power 1000-2000 W and ultrasonic frequency 20-40 kHz to obtain a mixed solution I.

[0015] S2, adding a sedimentation component to the mixed solution I, and ultrasonic stirring for 30-40 min under the condition of ultrasonic power 1000-2000 W and ultrasonic frequency 20-40 kHz to obtain a mixed solution II.

[0016] S3, adding a surface active component to the mixed solution II, stirring for 10-15 min at 400-800 r / min, and then adding a defoaming component, stirring for 5-10 min at 300-600 r / min to obtain a mixed solution III.

[0017] S4, adding an antibacterial component and a PH adjusting component to the mixed solution III, and stirring for 10-15 min at 500-1000 r / min to obtain a grinding fluid for ferrous metal processing.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] 1, the pyridine formaldehyde Schiff base, sodium thiosulfate and borate in the rust-proof component in the application synergize with each other and enhance each other in the rust-proof process, wherein the adsorption and film-forming property of the pyridine formaldehyde Schiff base provide a good adhesion basis for other components, the reducing property of the sodium thiosulfate protects the metal surface from oxidation corrosion, and the lubricity and rust-proof property of the borate further enhance the thickness and stability of the rust-proof film. This synergistic effect enables the entire rust-proof component to form a multi-layer and multi-dimensional rust-proof protection system on the metal surface.

[0020] 2、The potassium ferrocyanide, cyclodextrin and modified chitosan in the settling component in the application synergize and mutually enhance each other. The potassium ferrocyanide forms ion pairs or ion clusters with metal powder through ions ionized, which provides favorable conditions for subsequent adsorption and aggregation. The cyclodextrin envelopes part of the metal powder particles or forms a complex with the metal powder by using the cavity structure, changes the surface properties of the metal powder, and makes it more easily adsorbed by other components. The modified chitosan firmly adsorbs the metal powder by the three-dimensional network structure and metal chelating groups, and fixes it at the bottom of the grinding fluid. The interaction between these components forms a complex settling system, which acts on the metal powder particles in the grinding fluid together, so that the metal powder particles are quickly settled and kept at the bottom. The synergistic effect not only improves the settling efficiency, but also ensures the cleanliness and stability of the grinding fluid. DETAILED DESCRIPTION

[0021] In order to better understand the technical content of the application, the following specific examples are provided to further illustrate the application.

[0022] The experimental methods used in the embodiments of the application are conventional methods unless otherwise specified.

[0023] The materials, reagents, etc. used in the embodiments of the application can be obtained from commercial channels unless otherwise specified.

[0024] Example 1

[0025] A grinding fluid for ferrous metal processing, comprising the following raw materials by weight: 60 parts of deionized water, 15 parts of a lubricating component, 10 parts of an anti-rust component, 5 parts of a settling component, 4 parts of a surface active component, 3 parts of an antifoaming component, 3 parts of an antibacterial component, and 1 part of a pH adjusting component. The lubricating component is polyethylene glycol, the anti-rust component is composed of pyridine formaldehyde Schiff base, sodium thiosulfate and borate ester with a mass-volume ratio of 1:1:2, the settling component is composed of potassium ferrocyanide, cyclodextrin and modified chitosan with a mass ratio of 1:1:2, the surface active component is alkyl sulfonate, the antifoaming component is polysiloxane antifoaming agent, the antibacterial component is polyhexamethylene biguanide hydrochloride, and the pH adjusting component is sodium hydroxide.

[0026] The modified chitosan is prepared by the following method: chitosan is dissolved in pure water, and stirred at 50 DEG C until completely dissolved to form a chitosan solution. The mass / volume ratio g / mL of chitosan to pure water is 1:20. Glutaraldehyde is added to the above chitosan solution, and the pH value is adjusted to 4.5 to obtain reaction liquid I, which is stirred at 40 DEG C for 4 h to obtain crosslinked chitosan. The volume ratio of chitosan solution to glutaraldehyde is 10.0:2.5. After the reaction is completed, the reaction liquid I is poured into a Buchner funnel, and filtered under a vacuum degree of 0.05 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2 times, and then placed into a drying machine to be dried at 60 DEG C for 10 h. After the drying is completed, the crosslinked chitosan powder is ground in a mortar to obtain crosslinked chitosan powder. The crosslinked chitosan powder is dissolved in pure water, and stirred at 50 DEG C until completely dissolved to form a crosslinked chitosan solution. The mass / volume ratio g / mL of crosslinked chitosan powder to pure water is 1:30. Succinic anhydride is added to the above crosslinked chitosan solution, and the pH value is adjusted to 7.0 to obtain reaction liquid II, which is stirred at room temperature for 6 h. After the reaction is completed, the reaction liquid II is poured into a Buchner funnel, and filtered under a vacuum degree of 0.05 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2 times, and then placed into a drying machine to be dried at 60 DEG C for 12 h. After the drying is completed, the modified chitosan is ground in a mortar to obtain the modified chitosan.

[0027] The pyridine formaldehyde Schiff base is prepared by the following method: 2-pyridine formaldehyde is dissolved in ethanol to obtain a pyridine formaldehyde solution. The molar volume ratio mol / L of 2-pyridine formaldehyde to ethanol is 1:4. Ethylenediamine is dissolved in ethanol to obtain an ethylenediamine solution. The molar volume ratio mol / L of ethylenediamine to ethanol is 1:4. The pyridine formaldehyde solution is slowly added to the ethylenediamine solution at room temperature to obtain reaction liquid III, which is stirred for 4 h. After the reaction is completed, the reaction liquid III is poured into a Buchner funnel, and filtered under a vacuum degree of 0.05 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with ethanol for 2 times, and then recrystallized. The washed filter cake is recrystallized, and then dried at 55 DEG C for 6 h. After the drying is completed, the pyridine formaldehyde Schiff base is ground in a mortar to obtain the pyridine formaldehyde Schiff base.

[0028] Example 2

[0029] The grinding fluid for ferrous metal processing comprises the following raw materials by weight: 90 parts of deionized water, 25 parts of lubricating component, 20 parts of anti-rust component, 10 parts of sedimentation component, 8 parts of surface active component, 5 parts of defoaming component, 5 parts of antibacterial component, and 3 parts of pH adjusting component. The lubricating component is combined by phosphate ester and triethanolamine in a volume ratio of 1:1, the anti-rust component is composed of pyridine formaldehyde Schiff base, sodium thiosulfate and boric acid ester in a mass volume ratio g / mL of 3:2:4, the sedimentation component is composed of potassium ferrocyanide, cyclodextrin and modified chitosan in a mass ratio of 3:3:4, the surface active component is composed of alkylphenol polyoxyethylene ether and sulfobetaine in a mass volume ratio g / mL of 1:1, the defoaming component is a polyether defoaming agent, the antibacterial component is tetradecyl dimethyl benzyl ammonium chloride, and the pH adjusting component is potassium hydroxide.

[0030] The modified chitosan is prepared by the following method: chitosan is dissolved in pure water, and stirred at 60 DEG C until completely dissolved to form a chitosan solution. The mass volume ratio g / mL of chitosan to pure water is 1:40. Glutaraldehyde is added to the chitosan solution, and the pH value is adjusted to 5.5 to obtain reaction liquid I, which is stirred at 50 DEG C for 2 hours to obtain crosslinked chitosan. The volume ratio of chitosan solution to glutaraldehyde is 10.0:3.5. After the reaction is completed, the reaction liquid I is poured into a Buchner funnel, and filtered under a vacuum degree of 0.10 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 3 times, and then placed into a drying machine to be dried at 80 DEG C for 6 hours. After the drying is completed, the crosslinked chitosan powder is ground in a mortar to obtain crosslinked chitosan powder. The crosslinked chitosan powder is dissolved in pure water, and stirred at 60 DEG C until completely dissolved to form a crosslinked chitosan solution. The mass volume ratio g / mL of crosslinked chitosan powder to pure water is 1:60. Succinic anhydride is added to the crosslinked chitosan solution, and the pH value is adjusted to 8.0 to obtain reaction liquid II, which is stirred at room temperature for 4 hours. After the reaction is completed, the reaction liquid II is poured into a Buchner funnel, and filtered under a vacuum degree of 0.10 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2-3 times, and then placed into a drying machine to be dried at 70 DEG C for 8 hours. After the drying is completed, the modified chitosan is ground in a mortar.

[0031] The pyridine formaldehyde Schiff base is prepared by the following method: 2-pyridine formaldehyde is dissolved in ethanol to obtain a pyridine formaldehyde solution. The molar volume ratio of 2-pyridine formaldehyde to ethanol is 1:6. Ethylenediamine is dissolved in ethanol to obtain an ethylenediamine solution. The molar volume ratio of ethylenediamine to ethanol is 1:6. The pyridine formaldehyde solution is slowly added to the ethylenediamine solution at room temperature to obtain a reaction liquid III. The reaction is stirred for 4 hours. After the reaction is completed, the reaction liquid III is poured into a Buchner funnel and filtered under a vacuum degree of 0.10 MPa. After the filtration is completed, the filter cake is taken out of the Buchner funnel and washed with ethanol for 3 times. The washed filter cake is recrystallized, dried at 65 DEG C for 4 hours, ground in a mortar, and the pyridine formaldehyde Schiff base is obtained.

[0032] Example 3

[0033] A grinding fluid for ferrous metal processing comprises the following raw materials by weight: 75 parts of deionized water, 20 parts of a lubricating component, 15 parts of an antirust component, 7.5 parts of a sedimentation component, 6 parts of a surface active component, 4 parts of an antifoaming component, 4 parts of an antibacterial component, and 2 parts of a pH adjusting component. The lubricating component is composed of polypropylene glycol, fatty acid amide, and monoethanolamine in a volume ratio of 1:1:1, the antirust component is composed of pyridine formaldehyde Schiff base, sodium thiosulfate, and boric acid ester in a mass-volume ratio g / mL of 2:1.5:3, the sedimentation component is composed of potassium ferrocyanide, cyclodextrin, and modified chitosan in a mass ratio of 2:2:3, the surface active component is composed of alkyl benzene sulfonate, polyoxyethylene fatty acid ester, and saponin in a mass-volume ratio g / mL of 1:1:1, the antifoaming component is composed of polyether antifoaming agent and polyurea antifoaming agent in a volume ratio of 1:1, the antibacterial component is composed of polyhexamethylene biguanide hydrochloride, tetradecyl dimethyl benzyl ammonium chloride, and isothiazolinone in a mass ratio of 1:1:1, and the pH adjusting component is sodium carbonate.

[0034] The modified chitosan is prepared by the following method: chitosan is dissolved in pure water, and stirred at 55 DEG C until completely dissolved to form a chitosan solution. The mass / volume ratio g / mL of chitosan to pure water is 1:30. Glutaraldehyde is added to the chitosan solution, and the pH value is adjusted to 5.0 to obtain reaction liquid I, which is stirred at 45 DEG C for 3 hours to obtain cross-linked chitosan. The volume ratio of chitosan solution to glutaraldehyde is 10.0:3.0. After the reaction is completed, the reaction liquid I is poured into a Buchner funnel, and filtered under a vacuum degree of 0.08 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 3 times, and then placed into a drying machine to be dried at 70 DEG C for 8 hours. After the drying is completed, the cross-linked chitosan powder is obtained by grinding in a mortar. The cross-linked chitosan powder is dissolved in pure water, and stirred at 55 DEG C until completely dissolved to form a cross-linked chitosan solution. The mass / volume ratio g / mL of cross-linked chitosan powder to pure water is 1:45. Succinic anhydride is added to the cross-linked chitosan solution, and the pH value is adjusted to 7.5 to obtain reaction liquid II, which is stirred at room temperature for 5 hours. After the reaction is completed, the reaction liquid II is poured into a Buchner funnel, and filtered under a vacuum degree of 0.08 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 3 times, and then placed into a drying machine to be dried at 65 DEG C for 10 hours. After the drying is completed, the modified chitosan is obtained by grinding in a mortar.

[0035] The pyridine formaldehyde Schiff base is prepared by the following method: 2-pyridine formaldehyde is dissolved in ethanol to obtain a pyridine formaldehyde solution. The molar volume ratio mol / L of 2-pyridine formaldehyde to ethanol is 1:5. Ethylenediamine is dissolved in ethanol to obtain an ethylenediamine solution. The molar volume ratio mol / L of ethylenediamine to ethanol is 1:5. The pyridine formaldehyde solution is slowly added to the ethylenediamine solution at room temperature to obtain reaction liquid III, which is stirred for 2-4 hours. After the reaction is completed, the reaction liquid III is poured into a Buchner funnel, and filtered under a vacuum degree of 0.08 MPa. After the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with ethanol for 3 times, and then subjected to recrystallization treatment. After the washing, the filter cake is dried at 60 DEG C for 5 hours. After the drying is completed, the pyridine formaldehyde Schiff base is obtained by grinding in a mortar.

[0036] The grinding fluid for black metal machining described in the above embodiments 1-3 is prepared by the following method, which comprises the following steps:

[0037] S1, a lubricating component and a rust-proof component are added to deionized water, and ultrasonic stirring is performed under the conditions of an ultrasonic power of 1500 W and an ultrasonic frequency of 30 kHz for 25 min to obtain a mixed liquid I.

[0038] S2, the sedimentation component is added to the mixed liquid I, and ultrasonic stirring is performed under the conditions of an ultrasonic power of 1500 W and an ultrasonic frequency of 30 kHz for 35 min to obtain a mixed liquid II.

[0039] S3, adding the surface active component to the mixed solution II, stirring at 600 r / min for 12.5 min, then adding the defoaming component, stirring at 450 r / min for 7.5 min, to obtain a mixed solution III.

[0040] S4, adding the antibacterial component and the PH adjusting component to the mixed solution III, stirring at 750 r / min for 12.5 min, to obtain a grinding fluid for black metal machining.

[0041] Example 4

[0042] Example 4 is compared with Example 3, the difference is that the grinding fluid for black metal machining of Example 4 is prepared by the following method, comprising the following steps:

[0043] S1, adding the lubricating component and the rust-proof component to the deionized water, ultrasonic stirring at 1000 W of ultrasonic power and 20 kHz of ultrasonic frequency for 30 min, to obtain a mixed solution I.

[0044] S2, adding the sedimentation component to the mixed solution I, ultrasonic stirring at 1000 W of ultrasonic power and 20 kHz of ultrasonic frequency for 40 min, to obtain a mixed solution II.

[0045] S3, adding the surface active component to the mixed solution II, stirring at 400 r / min for 15 min, then adding the defoaming component, stirring at 300 r / min for 10 min, to obtain a mixed solution III.

[0046] S4, adding the antibacterial component and the PH adjusting component to the mixed solution III, stirring at 500 r / min for 15 min, to obtain a grinding fluid for black metal machining.

[0047] Example 5

[0048] Example 5 is compared with Example 3, the difference is that the grinding fluid for black metal machining of Example 5 is prepared by the following method, comprising the following steps:

[0049] S1, adding the lubricating component and the rust-proof component to the deionized water, ultrasonic stirring at 2000 W of ultrasonic power and 40 kHz of ultrasonic frequency for 20 min, to obtain a mixed solution I.

[0050] S2, adding the sedimentation component to the mixed solution I, ultrasonic stirring at 2000 W of ultrasonic power and 40 kHz of ultrasonic frequency for 30 min, to obtain a mixed solution II.

[0051] S3, adding the surface active component to the mixed solution II, stirring at 800 r / min for 10 min, then adding the defoaming component, stirring at 600 r / min for 5 min, to obtain a mixed solution III.

[0052] S4, adding the anti-bacterial component and the PH adjusting component to the mixed solution III, stirring at 1000 r / min for 10 min, to obtain a grinding fluid for black metal processing.

[0053] Comparative Example 1

[0054] This comparative example is compared with Example 3, the difference is that the rust-proof component is composed of sodium thiosulfate and boric acid ester with a mass-volume ratio of 1.5:3 g / mL.

[0055] Comparative Example 2

[0056] This comparative example is compared with Example 3, the difference is that the raw material does not contain the sedimentation component.

[0057] Comparative Example 3

[0058] This comparative example is compared with Example 3, the difference is that the sedimentation component is composed of cyclodextrin and modified chitosan with a mass ratio of 2:3.

[0059] Comparative Example 4

[0060] This comparative example is compared with Example 3, the difference is that the sedimentation component is composed of potassium ferrocyanide and modified chitosan with a mass ratio of 2:2.

[0061] Comparative Example 5

[0062] This comparative example is compared with Example 3, the difference is that the sedimentation component is composed of potassium ferrocyanide and cyclodextrin with a mass ratio of 2:3.

[0063] I. Anti-rust performance test

[0064] The grinding fluids for black metal processing prepared in Examples 1-5 and Comparative Example 1 were diluted by adding 25 times deionized water, respectively, and the anti-rust performance test was carried out according to the standard 5.7 section of GB / T 6144-2010 "Synthetic Cutting Fluid". The test results are shown in Table 1.

[0065] Table 1

[0066] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Single sheet 24h A A A A A A Single sheet 48h A A A A A B Stack 4h No rust No rust No rust No rust No rust No rust Stack 8h No rust No rust No rust No rust No rust Light rust

[0067] As can be seen from Table 1, the grinding fluid for ferrous metal processing of the present application has excellent rust-proof performance, and its rust-proof performance is much higher than the standard requirement. As can be seen from the comparison of Examples 1-5 and Comparative Example 1, the pyridine formaldehyde Schiff base in the rust-proof component is essential to the rust-proof component, and the rust-proof performance of the rust-proof component lacking the pyridine formaldehyde Schiff base has greatly decreased. This is because the pyridine ring introduced by the pyridine formaldehyde Schiff base has strong polarity and electron cloud density, and this characteristic enables the pyridine ring to more easily form a coordination bond or adsorption with the metal surface, thereby being closely combined on the metal surface. The nitrogen atom on the pyridine ring can also provide a lone pair of electrons to form a coordination bond with the empty orbital of the metal surface, thereby stabilizing the electronic state of the metal surface and reducing the possibility of oxidation of the metal. In addition, the pyridine ring and the group connected thereto can form a dense protective film on the metal surface, thereby preventing the contact of corrosive media such as oxygen and water, thereby playing a rust-proof role. In addition, the nitrogen atom on the pyridine ring can also capture free radicals generated in the oxidation process of the metal, thereby preventing the oxidation chain reaction from proceeding, and further enhancing the antioxidant capacity. Therefore, through the above effects, the pyridine formaldehyde Schiff base can be more firmly adsorbed on the metal surface to form a stable rust-proof layer. The pyridine formaldehyde Schiff base, sodium thiosulfate and borate in the present application synergize and enhance each other in the rust-proof process, wherein the adsorbability and film-forming property of the pyridine formaldehyde Schiff base provide a good attachment basis for other components, the reducing property of the sodium thiosulfate protects the metal surface from oxidation erosion, and the lubricity and rust-proof property of the borate further enhance the thickness and stability of the rust-proof film. This synergistic effect enables the entire rust-proof component to form a multi-layer and multi-dimensional rust-proof protection system on the metal surface.

[0068] II. Sedimentation performance test

[0069] The grinding fluid for ferrous metal processing prepared in Examples 1-5 and Comparative Examples 2-5 was taken, diluted with 25 times of deionized water, and then 100 mL of the diluted grinding fluid was taken and placed in a transparent stoppered cylinder. 2 g of iron powder with a particle size of 1 μm was added to each grinding fluid, and then oscillated up and down 100 times with the same force. After standing for 3 min, the sedimentation volume of each group was observed. The test was repeated 3 times, and the average value was taken as the sedimentation volume and recorded in Table 2.

[0070] Table 2

[0071]

[0072] As can be seen from Table 2, the grinding fluid for ferrous metal processing of the present application greatly improves the sedimentation of grinding dust by adding the sedimentation component composed of potassium ferrocyanide, cyclodextrin and modified chitosan in a specific ratio, and the effect of Example 3 is the best.

[0073] By comparing Example 3 with Comparative Example 2, the potassium ferrocyanide in the settling component in Example 3 can ionize ferrous ions and cyanide ions in water. These ions can interact with the charges on the surface of the black metal powder generated during grinding to form ion pairs or ion clusters, thereby increasing the density of the metal powder and making it easier to settle. In addition, potassium ferrocyanide can also connect multiple metal powder particles together through bridging to form larger aggregates, accelerating the settling process. The cyclodextrin in the settling component in Example 3 can accommodate hydrophobic molecules or ions in its internal cavity. In the grinding fluid, cyclodextrin can use its cavity structure to envelope part of the metal powder particles or form complexes with them, thereby changing the surface properties of the metal powder and making it easier to be adsorbed or aggregated by other settling ingredients. The modified chitosan in the settling component in Example 3 forms a cross-linked chitosan with a three-dimensional network structure through modification by glutaraldehyde, providing a large number of adsorption sites. These sites can form stable chelates with metal ions on the surface of black metal powder, thereby firmly adsorbing the metal powder. At the same time, the modification treatment by succinic anhydride introduces carboxyl groups on the chitosan molecules, which can strongly interact with metal ions, further enhancing the adsorption effect. In addition, the three-dimensional network structure also makes the modified chitosan have excellent trapping ability, which can quickly capture and fix metal powder particles suspended in the grinding fluid. In addition, potassium ferrocyanide, cyclodextrin and modified chitosan can also synergize and enhance each other. Among them, potassium ferrocyanide forms ion pairs or ion clusters with metal powder through ionization, providing favorable conditions for subsequent adsorption and aggregation. Cyclodextrin uses its cavity structure to envelope part of the metal powder particles or form complexes with them, changing the surface properties of the metal powder and making it easier to be adsorbed by other ingredients. Modified chitosan, through its three-dimensional network structure and metal chelating groups, firmly adsorbs the metal powder and fixes it at the bottom of the grinding fluid. The interaction between these components forms a complex settling system, which collectively acts on the metal powder particles in the grinding fluid, making them quickly settle and remain at the bottom. This synergistic effect not only improves the settling efficiency, but also ensures the cleanliness and stability of the grinding fluid.

[0074] By comparing Example 3 with Comparative Examples 3-5, the potassium ferrocyanide, cyclodextrin and modified chitosan in the settling component each have a unique settling principle, and they collectively improve the settling performance of the grinding fluid through interaction. The absence of any one of these components will significantly affect the settling performance of the grinding fluid. Therefore, these three components are indispensable in the settling component of the grinding fluid, and they collectively constitute the high-efficiency settling performance of the grinding fluid.

[0075] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A grinding fluid for ferrous metal working, characterized by, The composition comprises the following raw materials by weight: 60-90 parts of deionized water, 15-25 parts of a lubricating component, 10-20 parts of an anti-rust component, 5-10 parts of a sedimentation component, 4-8 parts of a surface active component, 3-5 parts of an antifoaming component, 3-5 parts of an antibacterial component, and 1-3 parts of a pH adjusting component, wherein the sedimentation component is composed of potassium ferrocyanide, cyclodextrin and modified chitosan in a mass ratio of (1-3):(1-3):(2-4), and the anti-rust component is composed of pyridine formaldehyde Schiff base, sodium thiosulfate and borate ester in a mass / volume ratio g / mL of (1-3):(1-2):(2-4). The modified chitosan is prepared by the following method: chitosan is dissolved in pure water and stirred at 50-60°C until completely dissolved to form a chitosan solution, wherein the mass / volume ratio g / mL of the chitosan and the pure water is 1:(20-40); glutaraldehyde is added to the chitosan solution, and the pH value is adjusted to 4.5-5.5 to obtain reaction liquid I, which is stirred at 40-50°C for 2-4h to obtain crosslinked chitosan, wherein the volume ratio of the chitosan solution and the glutaraldehyde is 10.0:(2.5-3.5); after the reaction is completed, the reaction liquid I is poured into a Buchner funnel and filtered under a vacuum degree of 0.05-0.10 MPa, after the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2-3 times, and then placed in a drying machine for drying at 60-80°C for 6-10h, after the drying is completed, the crosslinked chitosan powder is obtained by grinding in a mortar; the crosslinked chitosan powder is dissolved in pure water and stirred at 50-60°C until completely dissolved to form a crosslinked chitosan solution, wherein the mass / volume ratio g / mL of the crosslinked chitosan powder and the pure water is 1:(30-60); succinic anhydride is added to the crosslinked chitosan solution, and the pH value is adjusted to 7.0-8.0 to obtain reaction liquid II, which is stirred at room temperature for 4-6h, after the reaction is completed, the reaction liquid II is poured into a Buchner funnel and filtered under a vacuum degree of 0.05-0.10 MPa, after the filtration is completed, the filter cake is taken out from the Buchner funnel, washed with deionized water for 2-3 times, and then placed in a drying machine for drying at 60-70°C for 8-12h, after the drying is completed, the modified chitosan is obtained by grinding in a mortar.

2. The grinding fluid for ferrous metal working according to claim 1, characterized by, The pyridine formaldehyde Schiff base is prepared by the following method: 2-pyridine formaldehyde is dissolved in ethanol to obtain a pyridine formaldehyde solution, the molar volume ratio of the 2-pyridine formaldehyde to ethanol is 1:(4-6) mol / L; ethylenediamine is dissolved in ethanol to obtain an ethylenediamine solution, the molar volume ratio of the ethylenediamine to ethanol is 1:(4-6) mol / L; the pyridine formaldehyde solution is slowly added to the ethylenediamine solution at room temperature to obtain a reaction liquid III, the reaction is stirred for 2-4 h, after the reaction is completed, the reaction liquid III is poured into a Buchner funnel, is filtered under a vacuum degree of 0.05-0.10 MPa, after the filtration is completed, the filter cake is taken out from the Buchner funnel, then the filter cake is washed with ethanol for 2-3 times, the washed filter cake is subjected to recrystallization treatment, then is dried at 55-65 °C for 4-6 h, after the drying is completed, is ground in a mortar to obtain the pyridine formaldehyde Schiff base.

3. The grinding fluid for ferrous metal working according to claim 1, wherein The lubricating component is one or a combination of polyethylene glycol, polypropylene glycol, fatty acid amide, phosphate ester, triethanolamine and monoethanolamine.

4. The grinding fluid for ferrous metal working according to claim 1, wherein The pH adjusting component is one of sodium hydroxide, potassium hydroxide and sodium carbonate.

5. The grinding fluid for ferrous metal working according to claim 1, wherein The surface active component is one or a combination of alkyl sulfonate, alkyl benzene sulfonate, polyoxyethylene fatty acid ester, alkyl phenol polyoxyethylene ether, alkyl betaine, sulfobetaine and saponin.

6. The grinding fluid for ferrous metal working according to claim 1, wherein The defoaming component is one or a combination of polysiloxane defoaming agent, polyether defoaming agent, higher alcohol defoaming agent and polyurea defoaming agent.

7. The grinding fluid for ferrous metal working according to claim 1, wherein The antibacterial component is one or a combination of polyhexamethylene biguanide hydrochloride, dodecyl dimethyl benzyl ammonium chloride, tetradecyl dimethyl benzyl ammonium chloride and isothiazolinone.

8. A method of preparing a grinding fluid for ferrous metal working according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: S1, adding the lubricating component and the rust-proof component to deionized water, and stirring under ultrasonic power of 1000-2000 W and ultrasonic frequency of 20-40 kHz for 20-30 min to obtain a mixed liquid I; S2, adding the sedimentation component to the mixed liquid I, and stirring under ultrasonic power of 1000-2000 W and ultrasonic frequency of 20-40 kHz for 30-40 min to obtain a mixed liquid II; S3, adding the surface active component to the mixed liquid II, and stirring at 400-800 r / min for 10-15 min, then adding the defoaming component, and stirring at 300-600 r / min for 5-10 min to obtain a mixed liquid III; S4, adding the antibacterial component and the pH adjusting component to the mixed liquid III, and stirring at 500-1000 r / min for 10-15 min to obtain a grinding fluid for black metal machining.

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