Cooling liquid for metal bar peeling and preparation method thereof

Abstract

The invention discloses a cooling liquid for peeling a metal bar and a preparation method of the cooling liquid, and belongs to the field of chemical metallurgy. The corrosion inhibitor comprises the following components in parts by weight: 80-95 parts of a water-ethylene glycol mixed solution, 3-8 parts of composite boric acid ester, 0.5-3 parts of modified hydroxyethyl cellulose, 1-4 parts of sodium dinaphthyl methane disulfonate, 0.5-2 parts of a sodium molybdate-benzotriazole corrosion inhibitor and 0.1-1 part of a pH buffer agent. A B-O bond of boric acid ester of the composite boric acid ester reacts with a metal oxide to generate an iron borate composite film, so that excellent extreme pressure lubricity is provided, and friction between a cutter and a bar is reduced; the modified hydroxyethyl cellulose and the composite boric acid ester form a self-assembled micelle structure through a hydrophobic effect, so that the bearing capacity and the uniformity of the lubricating film are enhanced. The high performance of the cooling liquid is jointly realized through the lubrication synergy of the composite boric acid ester-HMHEC-sodium dinaphthyl methane disulfonate and the corrosion inhibition synergy of the sodium molybdate-benzotriazole-buffer agent.

Description

Technical Field

[0001] This invention belongs to the field of chemical metallurgy, and specifically relates to a coolant for peeling metal rods and its preparation method. Background Technology

[0002] In the field of metal bar processing, the peeling process is a key step in improving the surface quality of bars and removing oxide layers and defects. As the core auxiliary material of this process, the performance of coolant directly affects peeling efficiency, surface precision, equipment life and environmental friendliness.

[0003] Currently, the coolants commonly used for stripping metal bars present several technical challenges. In traditional mechanical stripping, while mineral oil-based coolants offer good lubrication, their limited heat dissipation capacity easily leads to excessive heat generation from friction between the cutting tool and the bar, causing surface burns or microcracks. Furthermore, their poor biodegradability results in environmental pollution after disposal. Water-based coolants, while providing rapid heat dissipation, lack sufficient lubrication, easily causing accelerated tool wear. They are also highly corrosive to metal bars (especially reactive metals such as copper alloys and low-carbon steel), requiring the addition of large amounts of corrosion inhibitors, which increases the complexity of the composition and the risk of residue buildup.

[0004] Patent application CN116042298A discloses a coolant containing hydraulic oil, diesel oil, tallow, and other components. Although it can improve the synergy between lubrication and heat dissipation by mixing oil phases, it has obvious defects: tallow, as a natural oil, is easily oxidized and rancid under high temperature and pressure, causing the coolant to deteriorate and smell bad, thus shortening its service life; the sodium carboxymethyl cellulose it contains, as a thickener, is easy to remain on the surface of equipment pipes and bars, forming a gel-like deposit, which not only affects the efficiency of the cooling circulation system, but also contaminates subsequent processing steps.

[0005] Furthermore, existing coolants lack adaptability to different types of bar stock. For example, due to the high hardness of stainless steel bars, ordinary coolants struggle to form a stable lubricating film, leading to excessive surface roughness during peeling (Ra often exceeds 3.2 μm). When processing copper alloys, sulfur and chlorine in the coolant can easily cause discoloration or intergranular corrosion, affecting product performance. Simultaneously, most coolants lack a long-lasting antioxidant system, making them prone to stratification or failure during continuous operation due to high temperatures and shear forces, requiring frequent replacements and increasing production costs and operational complexity.

[0006] With increasingly stringent environmental regulations and higher requirements for surface quality in high-end manufacturing, the shortcomings of existing coolants in terms of lubrication-heat dissipation balance, material compatibility, environmental friendliness, and service life are becoming increasingly prominent. There is an urgent need to develop a new type of coolant that combines high-efficiency lubrication, rapid heat dissipation, low corrosion, long service life, and environmental friendliness to meet the upgrading needs of metal bar stripping processes. Summary of the Invention

[0007] One of the objectives of this invention is to provide a coolant for peeling metal bars, reducing surface roughness and extending the service life of the mold;

[0008] The second objective of this invention is to provide a method for preparing a coolant for peeling metal rods, which is used to prepare the aforementioned coolant for peeling metal rods.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] A coolant for peeling metal rods, comprising, by weight, 80-95 parts water-ethylene glycol mixture, 3-8 parts composite borate ester, 0.5-3 parts modified hydroxyethyl cellulose, 1-4 parts sodium dinaphthylmethane disulfonate, 0.5-2 parts sodium molybdate-benzotriazole corrosion inhibitor, and 0.1-1 parts pH buffer.

[0011] Furthermore, the composite borate ester is prepared by the following steps:

[0012] S1. Add 2-mercaptobenzothiazole to the reaction vessel and add NaOH solution dropwise. Then add chloroethanol solution while stirring. Heat the mixture to 50-60℃ and react for 6-7 hours. Wash and extract, then vacuum distill to obtain 1-benzotriazole-ethanol.

[0013] S2. Dissolve 1-benzotriazole-ethanol in toluene, add boric acid and ethanolamine, stir and heat to 100-120℃ to react until no water is produced, and distill under reduced pressure to obtain the composite borate ester.

[0014] Furthermore, the weight ratio of the 2-mercaptobenzothiazole, NaOH, and chloroethanol is (15-20):(3-5):(5-9).

[0015] Furthermore, the ratio of the amount of 1-benzotriazole-ethanol, toluene, boric acid and ethanolamine is (14-19):(80-120):(4-8):(10-15).

[0016] Furthermore, the modified hydroxyethyl cellulose is prepared by the following steps:

[0017] Hydroxyethyl cellulose was dissolved in deionized water, and NaOH solution was slowly added dropwise. The mixture was heated and stirred for 30-40 minutes. A hydrophobic monomer dissolved in isopropanol was added, and the mixture was reacted at 70-80℃ for 4-5 hours. The pH was neutralized to 6.0-7.0, washed, dried, and pulverized to obtain hydrophobically modified hydroxyethyl cellulose.

[0018] Furthermore, the degree of substitution of the hydroxyethyl cellulose is 1.8-2.5, and the viscosity is 500-800 mPa·s.

[0019] Furthermore, the hydrophobic monomer is one or a combination of several of the following: long-chain alkyl glycidyl ether (C8-C18), allyltrimethylammonium chloride, dodecyl isocyanate, and hexadecane bromide.

[0020] Furthermore, the weight ratio of the hydroxyethyl cellulose to the hydrophobic monomer is 10:(1-2).

[0021] Furthermore, the weight ratio of deionized water to ethylene glycol in the water-ethylene glycol mixture is (40-60):(40-60).

[0022] Furthermore, the weight ratio of sodium molybdate to benzotriazole in the sodium molybdate-benzotriazole corrosion inhibitor is (2-2.5):1.

[0023] Furthermore, the pH buffer is a citrate-borate mixture; the citrate is one or a combination of sodium citrate and potassium citrate; the borate is one or a combination of borax and boric acid.

[0024] Furthermore, the weight ratio of citrate to borate is (3-5):1.

[0025] A method for preparing a coolant for peeling metal rods includes the following steps:

[0026] Mix the water-ethylene glycol mixture and the composite borate ester evenly, add the modified hydroxyethyl cellulose in batches, control the temperature at 20-30℃, add sodium dinaphthylmethane disulfonate and sodium molybdate-benzotriazole corrosion inhibitor, adjust the temperature back to 35-40℃, stir for 30-40 minutes, add pH buffer, stir for 1-2 hours, remove air bubbles and undispersed particles, filter and fill to obtain the cooling liquid for peeling metal rods.

[0027] The beneficial effects of this invention are:

[0028] (1) The BO bond of the borate ester (containing benzotriazole group) used in this invention reacts with metal oxide (such as Fe2O3) to generate an iron borate composite film, which provides excellent extreme pressure lubrication and reduces friction between the tool and the rod. The modified hydroxyethyl cellulose forms a microcrystalline structure in the water-ethylene glycol system, which improves solubility and reduces the amount of residue compared with sodium carboxymethyl cellulose, thus avoiding pipe blockage and surface contamination. On the other hand, the alkyl chain of the modified hydroxyethyl cellulose and the hydrophobic group of the composite borate ester form a self-assembled micelle structure through hydrophobic interaction, which enhances the load-bearing capacity and uniformity of the lubricating film. The micelle structure releases the active components of the borate ester under high temperature and high pressure, dynamically repairs the lubricating film, and avoids surface scratches caused by shear failure of traditional lubricants.

[0029] (2) The sodium dinaphthylmethane disulfonate used in this invention is a highly efficient dispersant that prevents wear debris deposition, maintains the cleanliness of the coolant, and adsorbs onto the surface of HMHEC through π-π stacking, promoting its uniform spreading at the metal interface to form a continuous lubricating layer and reduce friction loss. Sodium molybdate generates a MoO3 / FeMoO4 composite passivation film on the metal surface through oxidation, inhibiting electrochemical corrosion; benzotriazole complexes with copper ions to form a Cu-BTA polymer, preventing intergranular corrosion of copper alloys. The combination of the two reduces the corrosion rate of the metal rod, achieving a broad-spectrum metal protection effect. In addition, a pH buffer maintains the system pH at 8.5-9.0 to ensure that the molybdate ions are in an active state, enhancing the density of the passivation film. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0031] Example 1

[0032] This embodiment provides a coolant for peeling metal rods, which is prepared through the following steps:

[0033] S1. Add 18 parts of 2-mercaptobenzothiazole to the reaction vessel and add a solution containing 4 parts of NaOH dropwise. Then, add a solution containing 7 parts of chloroethanol while stirring. Heat the mixture to 60°C and maintain for 6 hours. Wash the reaction product with water three times, extract with benzene, and then vacuum distill to obtain 1-benzotriazole-ethanol.

[0034] 17 parts of 1-benzotriazole-ethanol were added to a reaction vessel with 100 parts of toluene as solvent, followed by 6 parts of boric acid and 13 parts of ethanolamine. The mixture was heated to 120°C with stirring, and the reaction was stopped until no water was produced. The product was then distilled under reduced pressure to obtain a complex borate ester.

[0035] S2. Dissolve 10 parts of hydroxyethyl cellulose (degree of substitution 2, viscosity 600 mPa·s) in 80 parts of deionized water, slowly add NaOH solution, heat and stir for 30 minutes, add 1.5 parts of dodecyl glycidyl ether dissolved in 15 parts of isopropanol, react at 80℃ for 4 hours, neutralize with acetic acid to pH=6.5, wash 3 times with 80% isopropanol to remove salt, vacuum dry at 60℃, and pulverize to 200 mesh powder to obtain hydrophobic modified hydroxyethyl cellulose;

[0036] S3. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2.2:1), adjust the temperature back to 40℃, stir for 30 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 4:1), adjust the pH to 8.6 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and circulate twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0037] Example 2

[0038] The difference between this embodiment and Example 1 is that the main adjustment is to the composition of the pH buffer. The specific implementation steps of S3 are as follows:

[0039] S3. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2.2:1), adjust the temperature back to 40℃, stir for 30 min, add 0.5 parts of pH buffer (potassium citrate and borax in a weight ratio of 4:1), adjust the pH to 8.7 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and process twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0040] The remaining raw materials and preparation process are the same as in Example 1.

[0041] Example 3

[0042] The difference between this embodiment and Example 1 is that the main adjustment is to the pH buffer ratio. The specific implementation steps of S3 are as follows:

[0043] S3. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2.2:1), adjust the temperature back to 40℃, stir for 40 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 5:1), adjust the pH to 8.8 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and process twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0044] The remaining raw materials and preparation process are the same as in Example 1.

[0045] Example 4

[0046] The difference between this embodiment and Example 1 is that the ratio of sodium molybdate and benzotriazole is mainly adjusted. The specific implementation steps of S3 are as follows:

[0047] S3. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2:1), adjust the temperature back to 38℃, stir for 40 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 4:1), adjust the pH to 8.6 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 2 h, and circulate twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0048] The remaining raw materials and preparation process are the same as in Example 1.

[0049] Example 5

[0050] The difference between this embodiment and Example 1 is that the hydrophobic monomer of the modified hydroxyethyl cellulose is replaced. The specific implementation steps of S2 are as follows:

[0051] S2. Dissolve 10 parts of hydroxyethyl cellulose (degree of substitution 2, viscosity 600 mPa·s) in 80 parts of deionized water, slowly add NaOH solution, heat and stir for 30 minutes, add 1.5 parts of hexadecane bromodisc dissolved in 15 parts of isopropanol, react at 80℃ for 4 hours, neutralize with acetic acid to pH=6.5, wash 3 times with 80% isopropanol to remove salt, vacuum dry at 60℃, and pulverize to 200 mesh powder to obtain hydrophobic modified hydroxyethyl cellulose;

[0052] The remaining raw materials and preparation process are the same as in Example 1.

[0053] Example 6

[0054] The difference between this embodiment and Example 1 is that the main adjustment is to the ratio of the composite borate ester. The specific implementation steps of S1 are as follows:

[0055] S1. Add 18 parts of 2-mercaptobenzothiazole to the reaction vessel and add a solution containing 5 parts of NaOH dropwise. Then, add a solution containing 6 parts of chloroethanol while stirring. Heat the mixture to 60°C and maintain for 6 hours. Wash the reaction product with water three times, extract with benzene, and then vacuum distill to obtain 1-benzotriazole-ethanol.

[0056] 18 parts of 1-benzotriazole-ethanol were added to a reaction vessel with 100 parts of toluene as solvent, followed by 8 parts of boric acid and 11 parts of ethanolamine. The mixture was heated to 120°C with stirring, and the reaction was stopped until no water was produced. The product was then distilled under reduced pressure to obtain a complex borate ester.

[0057] The remaining raw materials and preparation process are the same as in Example 1.

[0058] Example 7

[0059] The difference between this embodiment and Example 1 is that the main adjustment is to the ratio of the composite borate ester. The specific implementation steps of S1 are as follows:

[0060] S1. Add 18 parts of 2-mercaptobenzothiazole to the reaction vessel and add a solution containing 3 parts of NaOH dropwise. Then, add a solution containing 8 parts of chloroethanol while stirring. Heat the mixture to 60°C and maintain it for 7 hours. Wash the reaction product with water 3 times, extract with benzene, and then vacuum distill to obtain 1-benzotriazole-ethanol.

[0061] 15 parts of 1-benzotriazole-ethanol were added to a reaction vessel containing 100 parts of toluene as solvent, followed by 5 parts of boric acid and 15 parts of ethanolamine. The mixture was heated to 120°C with stirring, and the reaction was stopped until no water was produced. The product was then distilled under reduced pressure to obtain a complex borate ester.

[0062] The remaining raw materials and preparation process are the same as in Example 1.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is that sodium molybdate is not added, and the specific implementation steps of S3 are as follows:

[0065] S3. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of benzotriazole corrosion inhibitor, adjust the temperature back to 40℃, stir for 30 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 4:1), adjust the pH to 8.6 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and circulate twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0066] The remaining raw materials and preparation process are the same as in Example 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that sodium dinaphthylmethane disulfonate is not added. The specific implementation steps of S3 are as follows:

[0069] S3. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add a total of 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2.2:1), adjust the temperature back to 40℃, stir for 30 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 4:1), adjust the pH to 8.6 through an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and circulate twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill into the container to obtain the cooling liquid for peeling metal rods.

[0070] The remaining raw materials and preparation process are the same as in Example 1.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that the hydroxyethyl cellulose is not modified. The specific implementation steps are as follows:

[0073] S1. Add 18 parts of 2-mercaptobenzothiazole to the reaction vessel and add a solution containing 4 parts of NaOH dropwise. Then, add a solution containing 7 parts of chloroethanol while stirring. Heat the mixture to 60°C and maintain for 6 hours. Wash the reaction product with water three times, extract with benzene, and then vacuum distill to obtain 1-benzotriazole-ethanol.

[0074] 17 parts of 1-benzotriazole-ethanol were added to a reaction vessel with 100 parts of toluene as solvent, followed by 6 parts of boric acid and 13 parts of ethanolamine. The mixture was heated to 120°C with stirring, and the reaction was stopped until no water was produced. The product was then distilled under reduced pressure to obtain a complex borate ester.

[0075] S2. Mix 90 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) and 5 parts of composite borate ester evenly. Add 1.5 parts of hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2.2:1), adjust the temperature back to 40℃, stir for 30 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 4:1), adjust the pH to 8.6 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and process twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0076] The remaining raw materials and preparation process are the same as in Example 1.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 1 is that no composite borate ester is added. The specific implementation steps are as follows:

[0079] S1. Dissolve 10 parts of hydroxyethyl cellulose (degree of substitution 2, viscosity 600 mPa·s) in 80 parts of deionized water, slowly add NaOH solution, heat and stir for 30 minutes, add 1.5 parts of dodecyl glycidyl ether dissolved in 15 parts of isopropanol, react at 80℃ for 4 hours, neutralize with acetic acid to pH=6.5, wash 3 times with 80% isopropanol to remove salt, vacuum dry at 60℃, and pulverize to 200 mesh powder to obtain hydrophobic modified hydroxyethyl cellulose;

[0080] S3. Mix 95 parts of water-ethylene glycol mixture (deionized water and ethylene glycol in a weight ratio of 1:1) evenly, add 1.5 parts of modified hydroxyethyl cellulose in batches, control the temperature at 25℃, add 2.5 parts of sodium dinaphthylmethane disulfonate and 1 part of sodium molybdate-benzotriazole corrosion inhibitor (sodium molybdate and benzotriazole in a weight ratio of 2.2:1), adjust the temperature back to 40℃, stir for 30 min, add 0.5 parts of pH buffer (sodium citrate and boric acid in a weight ratio of 4:1), adjust the pH to 8.6 using an online pH monitoring system, maintain low-speed stirring (200 rpm) for 1.5 h, and circulate twice using a high-pressure homogenizer (pressure 15 MPa) to remove air bubbles and undispersed particles. After filtration (pore size 5 μm), fill to obtain the cooling liquid for peeling metal rods.

[0081] The remaining raw materials and preparation process are the same as in Example 1.

[0082] Performance testing

[0083] 1. Surface roughness (Ra): According to GB / T 3505-2009 "Geometric Specifications for Products (GPS) Surface Structure Profile Method: Terminology, Definitions and Parameters", the coolant obtained in the various embodiments and comparative examples of this application was used for peeling metal rods to conduct surface roughness tests.

[0084] 2. Metal corrosion rate: According to GB / T 18175-2014 "Determination of corrosion inhibition performance of water treatment agents - rotating plate method", the coolant obtained from the various embodiments and comparative examples of this application was used for metal rod peeling to test the metal corrosion rate.

[0085] 3. Tool wear: According to GB / T 16461-2016 "Test of life of single-edge turning tools", the coolant obtained from the various embodiments and comparative examples of this application was used for peeling metal bars to test the tool wear.

[0086] 4. Coolant Residue: According to GB / T 12579-2002 "Determination of Foaming Characteristics of Lubricating Oil", the coolant obtained from the various embodiments and comparative examples of this application was used for stripping metal rods to test the coolant residue.

[0087] The results are shown in Table 1:

[0088] Table 1

[0089]

[0090] As shown in Table 1, the Ra value in the examples was 2.2-2.7 μm, and the tool flank wear VB was 0.25-0.32 mm, which was far superior to Comparative Example 2 (Ra = 5.0 μm, VB = 0.58 mm) and Comparative Example 4 (Ra = 6.3 μm, VB = 0.81 mm). The core lies in the synergistic effect of the composite borate ester and modified hydroxyethyl cellulose (HMHEC): the composite borate ester forms an iron borate lubricating film through BO bonds, and the hydrophobic chains of HMHEC and the hydrophobic groups of the borate ester self-assemble into micelles, releasing active components at high temperatures to dynamically repair the film structure; sodium dinaphthylmethane disulfonate promotes uniform spreading of the lubricating film through π-π stacking. Comparative Example 2, lacking this dispersant, suffered from discontinuous film, leading to increased friction; Comparative Example 4, lacking the composite borate ester, lost its extreme pressure lubrication core, resulting in a sharp increase in wear and roughness.

[0091] In the examples, the corrosion rate of steel was 0.013-0.016 mm / a, and that of copper was 0.009-0.013 mm / a, while in Comparative Example 1 (without sodium molybdate), the corrosion rate of steel reached 0.063 mm / a. The principle is that sodium molybdate and benzotriazole form a broad-spectrum protective layer: sodium molybdate forms a MoO3 / FeMoO4 passivation film on the steel surface, and benzotriazole complexes with copper ions to form a Cu-BTA protective film; a pH buffer maintains an alkaline environment of 8.5-9.0 to ensure molybdate activity. In Comparative Example 1, due to the lack of sodium molybdate, anodic dissolution of the steel could not be inhibited, leading to accelerated corrosion.

[0092] The residual amount in the examples was 1.3-1.8 mg / cm³. 2 Comparative Example 3 (unmodified hydroxyethyl cellulose) reached 6.3 mg / cm³. 2 This is because after hydrophobic modification, the alkyl chains of HMHEC have reduced hydrogen bond adsorption with the equipment surface, while unmodified hydroxyethyl cellulose has residue due to strong adsorption of hydrophilic groups, which confirms the advantage of low residue after modification.

[0093] In summary, the lubrication synergy of the composite borate ester-HMHEC-dinaphthylmethane disulfonate and the corrosion inhibition synergy of sodium molybdate-benzotriazole-buffer jointly achieve high performance of the coolant.

[0094] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A coolant for use in the scalping of metal bar, characterized in that, By weight, it includes 80-95 parts water-ethylene glycol mixture, 3-8 parts compound borate ester, 0.5-3 parts modified hydroxyethyl cellulose, 1-4 parts sodium dinaphthylmethane disulfonate, 0.5-2 parts sodium molybdate-benzotriazole corrosion inhibitor, and 0.1-1 parts pH buffer.

2. A coolant for use in the scalping of metal rod according to claim 1, characterized in that, The composite borate ester is prepared by the following steps: S1. Add 2-mercaptobenzothiazole to the reaction vessel and add NaOH solution dropwise. Then add chloroethanol solution while stirring. Heat the mixture to 50-60℃ and react for 6-7 hours. Wash and extract, then vacuum distill to obtain 1-benzotriazole-ethanol. S2. Dissolve 1-benzotriazole-ethanol in toluene, add boric acid and ethanolamine, stir and heat to 100-120℃ to react until no water is produced, and distill under reduced pressure to obtain the composite borate ester.

3. A coolant for use in the scalping of metal rod according to claim 2, wherein The weight ratio of 2-mercaptobenzothiazole, NaOH and chloroethanol is (15-20):(3-5):(5-9).

4. The coolant for the skinning of metal bars according to claim 2, characterized in that, The ratio of 1-benzotriazole-ethanol, toluene, boric acid and ethanolamine is (14-19):(80-120):(4-8):(10-15).

5. The coolant for the skinning of metal bars according to claim 1, characterized in that, The modified hydroxyethyl cellulose is prepared by the following steps: Hydroxyethyl cellulose was dissolved in deionized water, and NaOH solution was slowly added dropwise. The mixture was heated and stirred for 30-40 minutes. A hydrophobic monomer soluble in isopropanol was added, and the mixture was reacted at 70-80℃ for 4-5 hours. The pH was neutralized to 6.0-7.0, and the mixture was washed, dried, and pulverized to obtain hydrophobically modified hydroxyethyl cellulose. The degree of substitution of the hydroxyethyl cellulose is 1.8-2.5, and the viscosity is 500-800 mPa·s.

6. The coolant for peeling metal rods according to claim 5, characterized in that, The hydrophobic monomer is one or a combination of long-chain alkyl glycidyl ether (C8-C18), allyltrimethylammonium chloride, dodecyl isocyanate, and hexadecane bromide; the weight ratio of hydroxyethyl cellulose to the hydrophobic monomer is 10:(1-2).

7. The coolant for peeling metal rods according to claim 1, characterized in that, The weight ratio of deionized water to ethylene glycol in the water-ethylene glycol mixture is (40-60):(40-60); the weight ratio of sodium molybdate to benzotriazole in the sodium molybdate-benzotriazole corrosion inhibitor is (2-2.5):

1.

8. The coolant for peeling metal rods according to claim 1, characterized in that, The pH buffer is a citrate-borate mixture; the citrate is one or more combinations of sodium citrate and potassium citrate; the borate is one or more combinations of borax and boric acid.

9. A coolant for peeling metal rods according to claim 8, characterized in that, The weight ratio of citrate to borate is (3-5):

1.

10. A method for preparing a coolant for peeling metal rods, characterized in that, The preparation of the coolant according to any one of claims 1-9 comprises the following steps: Mix the water-ethylene glycol mixture and the composite borate ester evenly, add the modified hydroxyethyl cellulose in batches, control the temperature at 20-30℃, add sodium dinaphthylmethane disulfonate and sodium molybdate-benzotriazole corrosion inhibitor, adjust the temperature back to 35-40℃, stir for 30-40 minutes, add pH buffer, stir for 1-2 hours, remove air bubbles and undispersed particles, filter and fill to obtain the cooling liquid for peeling metal rods.

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