Low-residue easy-to-clean steel strip rolling coolant and preparation method thereof

Abstract

The application belongs to the technical field of metal processing fluid, and provides a low-residue and easy-to-clean steel strip rolling cooling fluid and a preparation method thereof. The steel strip rolling cooling fluid comprises base oil, polyhydric alcohol fatty acid ester, polyethylene glycol fatty acid ester, phosphorus-based adsorption lubricant, organic dicarboxylic acid, oil-soluble amine compound, oil-soluble dispersant, polyether ester type cleaning additive, defoaming agent and antioxidant. In the preparation, the base oil, the polyhydric alcohol fatty acid ester and the polyethylene glycol fatty acid ester are mixed, and then the phosphorus-based adsorption lubricant, the organic dicarboxylic acid, the oil-soluble amine compound, the oil-soluble dispersant, the polyether ester type cleaning additive, the defoaming agent and the antioxidant are added to obtain the steel strip rolling cooling fluid. The cooling fluid is helpful to form an oily lubricating film and a temporary surface protection adsorption layer in the steel strip rolling process, and reduces the composite residue formed by the oily component and iron powder, oxide scale particles and swarf in the oil phase / working fluid by improving the dispersion state of the iron powder, the oxide scale particles and the swarf in the oil phase / working fluid, which is beneficial to reduce the post-rolling surface residue and is suitable for the steel strip rolling cooling and lubricating process.

Description

Technical Field

[0001] This invention belongs to the field of metalworking fluid technology, and relates to a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. Background Technology

[0002] During steel strip rolling, continuous friction and deformation heat exist between the rolls and the steel strip surface, typically requiring the use of rolling coolant to cool, lubricate, and protect the rolling area. Oil-based steel strip rolling coolants usually use base oils and synthetic ester components as continuous lubricating media, combined with phosphorus-based extreme pressure lubricants, rust inhibitors, dispersants, defoamers, and antioxidants to form an oily lubricating film in the rolling contact area, reducing friction between the rolls and the steel strip and providing temporary protection for the steel strip surface between processes. However, in actual rolling, iron powder, oxide scale particles, and abrasive debris are continuously generated on the steel strip surface. These particles easily adsorb or become trapped with the oily lubricating and rust-inhibiting components in the coolant, and under rolling pressure and shearing action, they deposit together on the steel strip surface, affecting the stability of annealing, plating, coating, or other surface treatment processes.

[0003] To improve rolling lubrication and short-term rust prevention, existing coolants often require the introduction of lubricants, rust inhibitors, and extreme pressure lubricants with strong adsorption or adhesion properties. However, the oily adsorbed layer formed by these components on the steel strip surface is difficult to disperse and remove during subsequent degreasing and cleaning stages, easily leading to increased post-rolling residue. Conversely, simply reducing the content of oily components or improving degreasing and cleaning performance may weaken the boundary lubrication capacity of the rolling interface and the inter-process rust prevention capacity, resulting in increased friction, surface scratches, or a higher risk of short-term corrosion. Therefore, existing steel strip rolling coolants still face the challenge of simultaneously achieving lubrication and rust prevention performance with low residue and easy cleaning properties, especially in effectively reducing the complex residue formed by the co-deposition of rolled iron powder, oxide scale particles, and organic components. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a low-residue, easily cleanable steel strip rolling coolant and its preparation method. The steel strip rolling coolant is an oil-based composition with a base oil as the continuous phase, comprising base oil, polyol fatty acid esters, polyethylene glycol fatty acid esters, phosphorus-based adsorbent lubricants, organic dicarboxylic acids, oil-soluble amine compounds, oil-soluble dispersants, polyether ester-type cleaning aids, defoamers, and antioxidants. This coolant, used in the steel strip rolling process, helps to simultaneously address the needs for oil film lubrication, temporary surface protection, iron particle dispersion adjustment, degreasing and cleaning, and the re-spreading and recovery of disturbed oil films.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a low-residue, easy-to-clean steel strip rolling coolant, wherein the steel strip rolling coolant is an oil-based composition with a base oil as the continuous phase, and the steel strip rolling coolant comprises a base oil, polyol fatty acid esters, polyethylene glycol fatty acid esters, phosphorus-based adsorbent lubricants, organic dicarboxylic acids, oil-soluble amine compounds, oil-soluble dispersants, polyether ester-type cleaning aids, defoamers, and antioxidants.

[0007] The mass ratio of the above components is (45.0-75.0): (8.0-22.0): (3.0-10.0): (1.0-5.0): (0.5-3.0): (0.5-4.0): (1.0-5.0): (1.0-6.0): (0.05-0.3): (0.1-1.0).

[0008] Preferably, the base oil is one or more of mineral base oil, hydrogenated base oil, and polyalphaolefin base oil.

[0009] Preferably, the polyol fatty acid ester is at least one of trimethylolpropane oleate and neopentyl glycol dioleate.

[0010] Preferably, the polyethylene glycol fatty acid ester is one or more of polyethylene glycol monooleate, polyethylene glycol dioleate, polyethylene glycol monolaurate, and polyethylene glycol dilaurate, and the average relative molecular mass corresponding to the polyethylene glycol structure in the polyethylene glycol fatty acid ester is 400-600.

[0011] Preferably, the phosphorus-based adsorbent lubricant is one or more of tributyl phosphate, isooctyl phosphate, and di-n-butyl phosphite.

[0012] Preferably, the organic dicarboxylic acid is one or two of dodecenyl succinic acid and sebacic acid; the oil-soluble amine compound is one or more of oleic acid imidazoline, dodecylamine, octadecylamine, and cyclohexylamine; and the mass ratio of the organic dicarboxylic acid to the oil-soluble amine compound is 1:(0.8-2.0).

[0013] Preferably, the oil-soluble dispersant is at least one of polyisobutylene succinimide and polymethacrylate dispersant; the polyether ester type cleaning aid is one or more of polyoxyethylene dehydrated sorbitan monooleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.

[0014] Preferably, the defoamer is a siloxane defoamer; the antioxidant is one or two of hindered phenolic antioxidants and amine antioxidants.

[0015] In a second aspect, the present invention provides a method for preparing a low-residue, easy-to-clean steel strip rolling coolant as described in the first aspect, the method comprising the following steps:

[0016] S1, mix base oil, polyol fatty acid ester and polyethylene glycol fatty acid ester, stir to obtain oil-ester mixture;

[0017] S2, add phosphorus-based adsorbent lubricant, organic dicarboxylic acid and oil-soluble amine compound to oil-ester mixture, stir to obtain adsorption mixture;

[0018] S3, add oil-soluble dispersant and polyether ester cleaning aid to the adsorption mixture, stir, and obtain a dispersion mixture;

[0019] S4. Add defoamer and antioxidant to the dispersion mixture, stir, filter, and obtain the steel strip rolling coolant.

[0020] Preferably, in S1, the stirring temperature is 40-55℃; in S2, the stirring temperature is 45-60℃ and the stirring time is 30-90min; in S3, the stirring temperature is 35-50℃ and the stirring time is 20-60min; and in S4, the stirring time is 30-90min.

[0021] Base oil, as the continuous phase, serves as the dispersion medium for polyol fatty acid esters, polyethylene glycol fatty acid esters, phosphorus-based adsorbent lubricants, organic dicarboxylic acids, oil-soluble amine compounds, oil-soluble dispersants, polyether ester-type cleaning aids, defoamers, and antioxidants. In the rolling contact zone, base oil helps form a continuous oil film and provides the basis for the lubricating medium between the rolls and the strip. Polyol fatty acid ester molecules contain multiple ester groups and fatty acid segments. The ester groups can weakly adsorb onto polar sites on the strip surface, while the fatty acid segments spread at the metal-to-metal interface, contributing to the formation of an oily boundary lubricating film in the rolling contact zone. The fatty acid ester segments in polyethylene glycol fatty acid esters participate in oil film spreading, and the polyethylene glycol segments help improve the interfacial compatibility between the post-rolling oil film and the degreasing cleaning medium, making it relatively easier for oily residues to disperse and be removed from the strip surface during the degreasing cleaning stage.

[0022] Phosphate ester or phosphite ester groups in phosphorus-based adsorbent lubricants can undergo coordination adsorption and ion adsorption with iron oxides, hydroxylated iron sites, and exposed metal sites on the steel strip surface, forming phosphorus-based adsorption anchors at the rolling interface. Their alkyl segments are compatible with base oils and ester lubricants and participate in the spread of the oily boundary film. Rolling pressure and shearing action cause phosphorus-based adsorbent lubricants, polyol fatty acid esters, and polyethylene glycol fatty acid esters to accumulate at the metal interface, forming a lubrication interface containing phosphorus-based adsorption sites and ester slip segments, which helps reduce direct contact between the rolls and the steel strip.

[0023] Organic dicarboxylic acids and oil-soluble amine compounds form oil-soluble acid-amine salt structures in the oil phase. The carboxylate sites in this structure can undergo ion adsorption and coordination adsorption with iron oxides, hydrated iron oxides, and exposed iron atoms on the steel strip surface. The oil-soluble organic segments maintain this dispersion within the base oil and ester-based lubricating components. The oil-soluble acid-amine salt on the steel strip surface helps form a temporary surface protective adsorption layer, which, together with phosphorus-based adsorbed lubricants and ester-based lubricating components, constitutes a temporary surface protective interface for the lubricant. During rolling, the phosphorus-based adsorption sites and carboxylate adsorption sites act on the polar regions of the metal surface, giving the oil film a certain degree of interfacial re-spreading ability under shear disturbance.

[0024] Oil-soluble dispersants can adsorb near the iron oxide sites on the surfaces of iron powder, oxide scale particles, and grinding debris. Their oil-soluble segments extend into base oils and ester-based lubricants, facilitating the formation of a steric hindrance layer on the particle surface. This reduces particle agglomeration and the likelihood of oily lubricating / surface protection components being co-deposited within the particles. Fresh iron powder generated during rolling has a high interfacial energy, readily adsorbing phosphorus-based adsorbents, organic dicarboxylic acid amine salts, and ester-based lubricating components. After adsorption, the oil-soluble dispersant improves the dispersion stability of iron powder and oxide scale particles in the oil phase, reducing the chance of iron powder, oxide scale particles, and oily components co-depositing on the steel strip surface.

[0025] Polyether ester-type cleaning aids contain oil-compatible segments and polyether segments. The oil-compatible segments disperse the oil in the base oil and ester lubricating components, while the polyether segments help improve the interfacial compatibility between oily residues and the cleaning medium during the degreasing and cleaning stage. During post-rolling degreasing and cleaning, the polyether ester-type cleaning aid is distributed at the interface between oily residues and the cleaning medium, helping to reduce the interfacial resistance required for the oil film to detach from the steel strip surface, making it easier for loose oily residues, iron-containing particle residues, and adsorbed organic components to be dispersed and carried away by the cleaning medium. This component is not a primary source of lubricating film; its main function is in the degreasing and cleaning process of post-rolling oily residues.

[0026] Defoamers migrate to the gas-liquid interface during the rolling oil circulation spraying and agitation process, causing localized drainage and rupture of the foam film, which helps reduce the interference of foam on oil film supply, spray coverage, and filtration circulation. Antioxidants can capture free radicals or peroxides formed in base oils and ester components under conditions of heat, shear, and the presence of metal particles, inhibiting the oxidation of oil phase components to form gums and adhesive oxidation products, and reducing viscosity increase and residue increase caused by oxidation.

[0027] During the steel strip rolling process, the interface undergoes pressure, shearing, heating, cooling, and fluid erosion. Within the contact zone, base oil and ester lubricating components form a continuous oil film, phosphorus-based adsorbents form adsorption anchors on the metal surface, and organic dicarboxylic acid amine salts form a temporary anti-rust adsorption layer at adjacent polar sites. Oil-soluble dispersants adsorb and disperse iron powder and oxide scale particles. Outside the contact zone, oily components that are not firmly adsorbed onto metal sites redistribute with the oil phase flow. Oil-soluble dispersants reduce the probability of iron powder and oil film co-deposition, and polyether ester-type cleaning aids make it easier to disperse and remove post-rolling oily residues during the degreasing and cleaning stage.

[0028] The oil film re-adsorption and recovery effect in this scheme is manifested as the re-spreading and recovery of the disturbed oil film. During the rolling process, after the oily lubricating and anti-rust film on the steel strip surface is subjected to rolling shear, iron powder abrasion, and liquid flow scouring, the phosphorus-based adsorbed components, organic dicarboxylic acid amine salts, and ester lubricating components in local areas may shift, and the exposed metal sites are re-exposed. These exposed sites help to promote the migration of phosphorus-based adsorbed lubricants, organic dicarboxylic acid amine salts, polyol fatty acid esters, and polyethylene glycol fatty acid esters in the oil phase. The phosphorus-based adsorbed groups and carboxylic acid salt sites are re-adsorbed at the exposed metal sites, and the ester segments are re-spread at the interface, which helps to reform the temporary lubrication and surface protection interface in the disturbed area, thus exhibiting the oil film re-adsorption and re-spreading recovery effect. The oil-soluble dispersant helps to improve the iron powder and oxide scale particles, reducing the possibility of particles covering the exposed sites and affecting the oil film recovery process, so that the oil film re-spreading and recovery process can have a certain degree of continuity in the circulating contact of the rolling coolant.

[0029] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention uses base oil as the continuous phase and constructs an oily lubrication interface through the co-construction of polyol fatty acid esters and polyethylene glycol fatty acid esters. This allows the steel strip rolling coolant to form a boundary lubrication film in the rolling contact area, which helps improve the dispersion and removal of oily residues during subsequent degreasing and cleaning, reducing the possibility of oily components continuously adhering to the plate surface. Phosphorus-based adsorbents, organic dicarboxylic acids, and oil-soluble amine compounds work together to form a temporary lubrication and surface protection adsorption layer, improving boundary lubrication and temporary surface protection effects between rolling and other processes. Oil-soluble dispersants help adsorb and disperse iron powder, oxide scale particles, and wear debris generated during rolling, reducing the possibility of particles co-depositing with oily lubricating and rust-preventing components, thereby helping to improve the cleanliness of the post-rolled plate surface. Polyether ester-type cleaning aids help disperse and remove post-rolling oily residues during the degreasing and cleaning stage, while defoamers and antioxidants help maintain the stability of the oil during recycling. After the oil film is disturbed by shearing or particle abrasion, the active components in the working fluid can re-migrate and adsorb near the exposed metal sites, so that the temporary lubrication and rust prevention interface exhibits a re-adsorption and recovery effect. Attached Figure Description

[0030] Figure 1The flowchart illustrates the preparation method provided by this invention. Detailed Implementation

[0031] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0032] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0033] Example 1

[0034] This embodiment provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The preparation method is as follows: Figure 1 As shown, the preparation method specifically includes the following steps:

[0035] S1, mineral base oil, trimethylolpropane oleate and polyethylene glycol monooleate are mixed in a mass ratio of 45.0:14.0:10.0, wherein the average relative molecular mass corresponding to the polyethylene glycol structure in the polyethylene glycol monooleate is 400, and the mixture is stirred at 40°C to obtain an oil-ester mixture;

[0036] S2, add isooctyl acid phosphate, dodecenyl succinic acid and oleic acid imidazoline to the oil-ester mixture, wherein the mass ratio of isooctyl acid phosphate, dodecenyl succinic acid and oleic acid imidazoline is 2.5:3.0:2.4, and stir at 52°C for 90 min to obtain an adsorption mixture;

[0037] S3, add polymethyl methacrylate dispersant and polyoxyethylene dehydrated sorbitan monooleate to the adsorption mixture, wherein the mass ratio of polymethyl methacrylate dispersant to polyoxyethylene dehydrated sorbitan monooleate is 4.0:1.0, and stir at 45°C for 20 min to obtain a dispersion mixture;

[0038] S4, add siloxane defoamer and hindered phenolic antioxidant to the dispersion mixture, wherein the mass ratio of siloxane defoamer to hindered phenolic antioxidant is 0.15:1.0, stir for 60 min, filter, and obtain steel strip rolling coolant.

[0039] Example 2

[0040] This embodiment provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The preparation method specifically includes the following steps:

[0041] S1, Hydrogenated base oil, neopentyl glycol dioleate and polyethylene glycol dioleate are mixed in a mass ratio of 75.0:8.0:6.0, wherein the average relative molecular mass corresponding to the polyethylene glycol structure in the polyethylene glycol dioleate is 600, and the mixture is stirred at 55°C to obtain an oil-ester mixture;

[0042] S2, add tributyl phosphate, sebacic acid and dodecylamine to the oil-ester mixture, wherein the mass ratio of tributyl phosphate, sebacic acid and dodecylamine is 5.0:0.5:0.5, and stir at 45°C for 60 min to obtain an adsorption mixture;

[0043] S3, add polyisobutylene succinimide and polyoxyethylene castor oil to the adsorption mixture, wherein the mass ratio of polyisobutylene succinimide to polyoxyethylene castor oil is 1.0:4.5, and stir at 50°C for 40 min to obtain a dispersion mixture;

[0044] S4. Add siloxane defoamer and amine antioxidant to the dispersion mixture, wherein the mass ratio of siloxane defoamer to amine antioxidant is 0.3:0.45, stir for 30 min, filter, and obtain steel strip rolling coolant.

[0045] Example 3

[0046] This embodiment provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The preparation method specifically includes the following steps:

[0047] S1, polyalphaolefin base oil, trimethylolpropane oleate, neopentyl glycol dioleate and polyethylene glycol monolaurate are mixed in a mass ratio of 60.0:12.0:10.0:3.0, wherein the average relative molecular mass of the polyethylene glycol structure in the polyethylene glycol monolaurate is 500, and the mixture is stirred at 48°C to obtain an oil-ester mixture;

[0048] S2, add dibutyl phosphite, dodecenyl succinic acid, sebacic acid and octadecylamine to the oil-ester mixture, wherein the mass ratio of dibutyl phosphite, dodecenyl succinic acid, sebacic acid and octadecylamine is 1.0:1.4:0.8:4.0, and stir at 60°C for 30 min to obtain an adsorption mixture;

[0049] S3, add polyisobutylene succinimide, polymethacrylate dispersant and polyoxyethylene hydrogenated castor oil to the adsorption mixture, wherein the mass ratio of polyisobutylene succinimide, polymethacrylate dispersant and polyoxyethylene hydrogenated castor oil is 2.5:2.5:3.0, and stir at 35°C for 60 min to obtain a dispersion mixture;

[0050] S4, add siloxane defoamer and hindered phenolic antioxidant to the dispersion mixture, wherein the mass ratio of siloxane defoamer to hindered phenolic antioxidant is 0.05:0.1, stir for 90 min, filter, and obtain steel strip rolling coolant.

[0051] Example 4

[0052] This embodiment provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The preparation method specifically includes the following steps:

[0053] S1, mineral base oil, polyalphaolefin base oil, trimethylolpropane oleate and polyethylene glycol dilaurate are mixed in a mass ratio of 40.0:25.0:18.0:8.0, wherein the average relative molecular mass corresponding to the polyethylene glycol structure in the polyethylene glycol dilaurate is 550, and the mixture is stirred at 52°C to obtain an oil-ester mixture;

[0054] S2, add tributyl phosphate, isooctyl phosphate, dodecenyl succinic acid and oleic acid imidazoline to the oil-ester mixture, wherein the mass ratio of tributyl phosphate, isooctyl phosphate, dodecenyl succinic acid and oleic acid imidazoline is 2.0:2.0:1.5:1.5, and stir at 55°C for 75 min to obtain an adsorption mixture;

[0055] S3, add polymethyl methacrylate dispersant, polyoxyethylene dehydrated sorbitan monooleate and polyoxyethylene castor oil to the adsorption mixture, wherein the mass ratio of polymethyl methacrylate dispersant, polyoxyethylene dehydrated sorbitan monooleate and polyoxyethylene castor oil is 2.5:3.0:3.0, and stir at 42°C for 50 min to obtain a dispersion mixture;

[0056] S4, add siloxane defoamer, hindered phenolic antioxidant and amine antioxidant to the dispersion mixture, wherein the mass ratio of siloxane defoamer, hindered phenolic antioxidant and amine antioxidant is 0.22:0.35:0.40, stir for 45 min, filter to obtain steel strip rolling coolant.

[0057] Comparative Example 1

[0058] This comparative example provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The difference between this and Example 1 is that isooctyl phosphate in S2 is replaced with an equal mass of trimethylolpropane oleate. Other process parameters and operating conditions are exactly the same as in Example 1.

[0059] Comparative Example 2

[0060] This comparative example provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The difference between this and Example 1 is that polymethyl methacrylate dispersant is not added in S3, and is replaced by an equal mass of mineral base oil. Other process parameters and operating conditions are exactly the same as in Example 1.

[0061] Comparative Example 3

[0062] This comparative example provides a low-residue, easy-to-clean steel strip rolling coolant and its preparation method. The difference between this and Example 1 is that the polyethylene glycol monooleate in S1 is replaced with an equal mass of trimethylolpropane oleate, while the other process parameters and operating conditions are exactly the same as in Example 1.

[0063] Performance testing:

[0064] The obtained steel strip rolling cooling fluid was emulsified and diluted in deionized water under stirring to prepare a working fluid with a mass percentage of 4.0%. The test steel sheets were cold-rolled low-carbon steel sheets with dimensions of 100mm × 50mm × 0.8mm. Before testing, the steel sheet surface was cleaned sequentially with petroleum ether, anhydrous ethanol, and deionized water, then dried in a 60℃ oven for 30 minutes. After cooling to room temperature, the sheets were weighed and recorded as m0. Three pieces were tested in each group, and the average value was taken.

[0065] Method for testing surface residue after rolling: Take a pretreated steel sheet and evenly coat the surface with the working fluid to be tested, ensuring complete coverage of the test surface. Simulate rolling using a laboratory two-roll mill. Before rolling, clean and dry the roll surface. Control the rolling speed at 0.5 m / min and the reduction rate at 10%. Roll each steel sheet three times. During rolling, add the same working fluid to the steel sheet surface before each roll to maintain an oil film covering the test surface. After rolling, allow the steel sheet to stand at room temperature for 10 minutes, then dry it in a 60℃ oven for 30 minutes. After drying, cool to room temperature and weigh, recording the weight as m1. Calculate the surface residue after rolling using the following formula: Surface residue after rolling = (m1 - m0) / A, where A is the area of ​​the test surface of the steel sheet, in m². 2 The residual amount on the surface after rolling is expressed in mg / m³. 2 The lower the value, the less non-volatile residue remains on the surface of the rolled steel sheet.

[0066] Test method for surface residue rate after degreasing and cleaning: The same steel sheet was used for degreasing and cleaning. The steel sheet was fixed on a spray cleaning rack, and the test surface of the steel sheet was sprayed with an alkaline degreasing solution with a mass percentage of 3.0%. The degreasing solution temperature was 50℃, the spray pressure was 0.15MPa, the spray distance was 150mm, and the spray time was 60s. After spraying, it was rinsed with 25℃ deionized water for 30s. After rinsing, the steel sheet was placed in a 60℃ oven to dry for 30min, cooled to room temperature, and weighed, recorded as m2. The surface residue rate after degreasing and cleaning was calculated using the following formula: Surface residue rate after degreasing and cleaning = (m2 - m0) / (m1 - m0) × 100%, where m0 is the mass of the steel sheet before testing, m1 is the mass of the dried steel sheet after rolling, and m2 is the mass of the dried steel sheet after degreasing and cleaning. The lower the surface residue rate after degreasing and cleaning, the easier it is for the rolled residue to be removed by degreasing and cleaning.

[0067] Friction coefficient test method: The lubrication performance of the working fluid was tested using a reciprocating friction and wear testing machine. The lower sample was a pretreated cold-rolled low-carbon steel sheet, and the upper sample was a 6mm diameter GCr15 steel ball. The working fluid to be tested was dripped onto the surface of the steel sheet, so that the friction contact area was completely covered by the working fluid. The test load was 30N, the reciprocating frequency was 5Hz, the reciprocating stroke was 5mm, the test temperature was 40℃, and the test time was 30min. The friction coefficient was continuously recorded during the test, and the average friction coefficient within 10min after the test was taken as the friction coefficient of that group of working fluids. Each group was tested 3 times, and the average value was taken.

[0068] Oil film re-spreading recovery rate test method: The re-adsorption recovery performance of the adsorption film was tested using a reciprocating friction and wear testing machine. The lower sample was a pretreated cold-rolled low-carbon steel sheet, and the upper sample was a 6mm diameter GCr15 steel ball. The working fluid to be tested was dropped onto the surface of the steel sheet, so that the friction contact area was completely covered by the oil sample. The test was run for 10 minutes under the conditions of 30N load, 5Hz reciprocating frequency, 5mm reciprocating stroke, and 40℃, so that the adsorbed components in the working fluid formed a temporary lubricating adsorption film on the surface of the steel sheet. The average friction coefficient from the 8th to the 10th minute of the test was recorded as μ0. Then the friction test was stopped, and a diamond scriber was used to scratch the friction trajectory area three times in the vertical direction with a scratching load of 2N to destroy the local adsorption film. The same working fluid was immediately added after scratching, and the test was continued under the same friction conditions. The highest friction coefficient in the first 30 seconds after scratching was recorded as μ0. d Continue running for 5 minutes, and record the average friction coefficient for the last 2 minutes, denoted as μ. r The oil film redeployment recovery rate is calculated using the following formula: Oil film redeployment recovery rate = (μ d -μ r ) / (μ d -μ0)×100%, where μ0 is the stable friction coefficient before the adsorption film is destroyed, μd The peak friction coefficient after adsorption film damage is μ. r The coefficient of friction is the recovered value after adding working fluid and continuing friction. A higher re-adsorption recovery rate of the adsorption membrane indicates a stronger ability of the adsorption membrane to reform a temporary lubrication interface after being disturbed.

[0069] The test results are shown in Table 1.

[0070] Table 1. Test results of the strip rolling coolant in Examples 1-4 and Comparative Examples 1-3

[0071]

[0072] As shown in Table 1, compared with Example 1, Comparative Example 1 showed an increase in surface residue after rolling, an increase in surface residue rate after degreasing and cleaning, an increase in friction coefficient, and a decrease in oil film re-spreading recovery rate; Comparative Example 2 showed an increase in surface residue after rolling, an increase in surface residue rate after degreasing and cleaning, an increase in friction coefficient, and a decrease in oil film re-spreading recovery rate; and Comparative Example 3 showed an increase in surface residue after rolling, an increase in surface residue rate after degreasing and cleaning, a decrease in friction coefficient, and a decrease in oil film re-spreading recovery rate.

[0073] This is because, in Comparative Example 1, replacing isooctyl phosphate with trimethylolpropane oleate resulted in a lack of components in the system that could form phosphorus-based adsorption anchors with the steel strip surface. This reduced the oil film's ability to re-spread after rolling shearing and iron powder abrasion, leading to an increased friction coefficient and a lower oil film re-spreading recovery rate. Simultaneously, the absence of phosphorus-based adsorption anchors decreased the stability of the boundary lubricating film, increasing the disturbance to the interface caused by rolling shearing and particle abrasion. This increased the likelihood of iron powder, oxide scale particles, and oily components forming mixed residues, thus raising the post-rolling surface residue and the surface residue rate after degreasing and cleaning. In Comparative Example 2, without the addition of polymethyl methacrylate dispersant, the iron powder, oxide scale particles, and grinding debris generated during rolling lacked corresponding oil phase dispersion regulation. The particles were more likely to carry oily lubricating components and surface protective components, depositing together on the steel strip surface, resulting in increased post-rolling surface residue and the surface residue rate after degreasing and cleaning. The particles may also disturb the continuity of the oil film, thereby increasing the friction coefficient and reducing the oil film re-spreading recovery rate. In Comparative Example 3, after replacing polyethylene glycol monooleate with trimethylolpropane oleate, the oily ester segments could still participate in boundary lubrication, thus reducing the coefficient of friction. However, the system lacked the regulatory effect of polyethylene glycol segments on the dispersion and removal of oil film during the degreasing and cleaning stage. The oily residue after rolling was relatively more difficult to be removed by the cleaning medium, resulting in an increase in the amount of surface residue after rolling and the surface residue rate after degreasing and cleaning. At the same time, the migration and re-spreading ability of the disturbed oil film decreased.

[0074] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A low-residue, easy-to-clean steel strip rolling coolant, characterized in that, The strip rolling coolant is an oil-based composition with base oil as the continuous phase. The strip rolling coolant includes base oil, polyol fatty acid esters, polyethylene glycol fatty acid esters, phosphorus-based adsorbent lubricants, organic dicarboxylic acids, oil-soluble amine compounds, oil-soluble dispersants, polyether ester cleaning aids, defoamers, and antioxidants. The mass ratio of the above components is (45.0-75.0): (8.0-22.0): (3.0-10.0): (1.0-5.0): (0.5-3.0): (0.5-4.0): (1.0-5.0): (1.0-6.0): (0.05-0.3): (0.1-1.0).

2. The low-residue, easy-to-clean steel strip rolling coolant according to claim 1, characterized in that, The base oil is one or more of mineral base oil, hydrogenated base oil, and polyalphaolefin base oil.

3. The low-residue, easy-to-clean steel strip rolling coolant according to claim 1, characterized in that, The polyol fatty acid ester is at least one of trimethylolpropane oleate and neopentyl glycol dioleate.

4. The low-residue, easy-to-clean steel strip rolling coolant according to claim 1, characterized in that, The polyethylene glycol fatty acid ester is one or more of polyethylene glycol monooleate, polyethylene glycol dioleate, polyethylene glycol monolaurate, and polyethylene glycol dilaurate, and the average relative molecular mass corresponding to the polyethylene glycol structure in the polyethylene glycol fatty acid ester is 400-600.

5. The low-residue, easy-to-clean steel strip rolling coolant according to claim 1, characterized in that, The phosphorus-based adsorbent lubricant is one or more of tributyl phosphate, isooctyl phosphate, and di-n-butyl phosphite.

6. The low-residue, easy-to-clean steel strip rolling coolant according to claim 1, characterized in that, The organic dicarboxylic acid is one or two of dodecenyl succinic acid and sebacic acid; the oil-soluble amine compound is one or more of oleic acid imidazoline, dodecylamine, octadecylamine, and cyclohexylamine; the mass ratio of the organic dicarboxylic acid to the oil-soluble amine compound is 1:(0.8-2.0).

7. The low-residue, easy-to-clean steel strip rolling coolant according to claim 1, characterized in that, The oil-soluble dispersant is at least one of polyisobutylene succinimide and polymethacrylate dispersant; the polyether ester cleaning aid is one or more of polyoxyethylene dehydrated sorbitan monooleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.

8. A low-residue, easy-to-clean steel strip rolling coolant according to any one of claims 1-7, characterized in that, The defoamer is a siloxane defoamer; the antioxidant is one or two of hindered phenolic antioxidants and amine antioxidants.

9. A method for preparing a low-residue, easy-to-clean steel strip rolling coolant as described in any one of claims 1-8, characterized in that, The preparation method includes the following steps: S1, mix base oil, polyol fatty acid ester and polyethylene glycol fatty acid ester, stir to obtain oil-ester mixture; S2, add phosphorus-based adsorbent lubricant, organic dicarboxylic acid and oil-soluble amine compound to oil-ester mixture, stir to obtain adsorption mixture; S3, add oil-soluble dispersant and polyether ester cleaning aid to the adsorption mixture, stir, and obtain a dispersion mixture; S4. Add defoamer and antioxidant to the dispersion mixture, stir, filter, and obtain the steel strip rolling coolant.

10. The method for preparing a low-residue, easy-to-clean steel strip rolling coolant according to claim 9, characterized in that, In S1, the stirring temperature is 40-55℃; in S2, the stirring temperature is 45-60℃, and the stirring time is 30-90 min.

11. The method for preparing a low-residue, easy-to-clean steel strip rolling coolant according to claim 9, characterized in that, In S3, the stirring temperature is 35-50℃ and the stirring time is 20-60 min; in S4, the stirring time is 30-90 min.

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