Rolling mill for Hi-B steel and method for its preparation

Abstract

Disclosed are a rolling agent for Hi-B steel and a method for preparing the same. The rolling agent for Hi-B steel includes a modified triazine acid having a structural formula as follows:

Description

Technical Field

[0001] This invention relates to a rolling compound, and more particularly to a rolling compound for Hi-B steel and its preparation method. Background Technology

[0002] Due to increasingly stringent requirements for energy conservation and emission reduction, relevant national departments are considering revising and strengthening the standards for upgrading transformer energy efficiency, particularly for distribution transformers. This will place new demands on the grades, specifications, and performance levels of grain-oriented electrical steel. In the future, the use of general grain-oriented electrical steel (CGO steel) will gradually decrease, while the use of high-magnetic-induction grain-oriented electrical steel (Hi-B steel) will gradually increase or expand.

[0003] With the increasing demand for Hi-B steel, the quality requirements for cold-rolled Hi-B steel plates are becoming increasingly stringent, especially the requirements for corrosion resistance after rolling. Therefore, it is imperative to invent a new high-corrosion-resistant Hi-B steel rolling medium.

[0004] The difference between Hi-B steel and ordinary silicon steel lies in their higher silicon content. Ferrosilicon alloys easily form galvanic cells on the steel plate surface. As the silicon content increases, the corrosion potential decreases, making it more susceptible to corrosion. Secondly, their rolling temperatures differ. With increasing silicon content, the yield strength and tensile strength of the steel significantly increase, along with its hardness. This results in increasingly larger reductions during rolling, decreasing the material's toughness and making it prone to grain breakage and band fracture, impacting production output. Therefore, high-temperature rolling is often used to prevent grain breakage. However, during high-temperature rolling, the temperature in the roll gap area is very high, requiring rust-inhibiting additives with strong adsorption properties to adhere firmly to the steel plate and achieve good corrosion protection. This poses a challenge to cold-rolling oils for silicon steel.

[0005] Existing rolling media for Hi-B steel mainly utilize traditional benzoazole and sulfonate additives. Both of these rust-inhibiting additives have shortcomings when used in the rolling process of Hi-B steel, specifically in the following aspects:

[0006] (1) Due to the special nature of Hi-B steel, high-temperature rolling is often used to avoid strip breakage and grain breakage during the rolling process. As the temperature rises during the rolling process, the adsorption of these two types of additives on the metal surface will weaken, resulting in desorption and reducing the anti-corrosion effect.

[0007] (2) Because Hi-B steel is rolled at high temperatures, benzoazole additives will emit an extremely foul odor when used under high-temperature conditions, polluting the surrounding environment.

[0008] (3) Sulfonate additives will form metal salt residues on the surface of the rolled plate, which will affect the cleaning of the surface of the rolled plate and the subsequent annealing, greatly increasing the defect rate of the product.

[0009] Based on the above background, it is necessary to design a new type of rolling medium suitable for Hi-B steel.

[0010] Studies have shown that modified triazine acid, through the synergistic effect of ester, amide, and carboxylic acid bonds, can be effectively adsorbed onto the surface of steel strip, forming a well-oriented and tightly packed hydrophobic monolayer. This effectively reduces the transport capacity of water molecules, oxygen molecules, and electrons to the metal surface, shifting the critical potential for oxidation of the base metal positively and significantly reducing the oxidation-reduction current on the metal surface, thus protecting the silicon steel surface. Furthermore, the thermal stability of amide and carboxylic acid groups reduces the probability of their desorption from the silicon steel surface under high-temperature conditions. The synergistic effect of the three functional groups (ester, amide, and acid) forms a denser protective layer, providing excellent corrosion protection under high-temperature rolling conditions. Finally, the larger molecular weight and synergistic adsorption of acid, amide, and ester bonds create a more efficient and robust adsorption film on the silicon steel surface, providing not only corrosion protection but also excellent lubrication. It increases lubrication between the strip and the rolls, better protecting the work rolls and strip surface, and improving the quality of the strip. Modified triazinon acid is inexpensive, which greatly reduces the cost of rolling oil. Modified triazinon acid is not easily soluble in water, making it easy to treat wastewater in subsequent processes. Summary of the Invention

[0011] To solve the above-mentioned technical problems, the present invention provides a rolling mill for Hi-B steel, wherein the rolling mill for Hi-B steel comprises:

[0012] Modified triazine acid 1.5-3.0%;

[0013] Natural oils 30.0%–50.0%;

[0014] Synthetic esters 10.0%–30.0%

[0015] Mineral oil 20.0%–40.0%;

[0016] Extreme pressure anti-wear additive 2.0%–10.0%

[0017] Antioxidant 0.3-0.9%;

[0018] The emulsifier is 0.8-3.5%, wherein the modified triazine acid has the following structural formula:

[0019]

[0020] It is worth mentioning that modified triazine acid, by utilizing the thermal stability of amide and carboxylic acid groups, reduces the probability of their desorption from the silicon steel sheet surface under high-temperature conditions. Furthermore, the three functional groups of different polarities—ester, amide, and acid—exhibit a synergistic effect, forming a denser protective layer, thus providing excellent corrosion protection under high-temperature rolling conditions. In addition, modified triazine acid, through its larger molecular size and the synergistic adsorption of acid, amide, and ester bonds, forms a more efficient and robust adsorption film on the silicon steel surface, which not only provides corrosion protection but also excellent lubrication. This increases lubrication between the strip and the rolls, better protecting the work rolls and strip surface, and improving the sheet quality.

[0021] In addition, modified triazine acid is inexpensive, which greatly reduces the cost of rolling mills used in Hi-B steel; on the other hand, modified triazine acid is not easily soluble in water, making it easy to treat downstream wastewater.

[0022] In a preferred embodiment, the groups R1, R2, and R3 are derived from the alkyl portion of coconut oil acid, oleic acid, stearic acid, linoleic acid, lauric acid, ricinoleic acid, tall oil acid, or palmitoleic acid, respectively.

[0023] In a preferred embodiment, the groups R1, R2, and R3 may be the same or different.

[0024] m is derived from the alkyl portion of palmitoleic acid or stearic acid, and n is derived from the alkyl portion of oleic acid or lauric acid.

[0025] In a preferred embodiment, the natural oil is selected from one or a mixture of at least two of lard, coconut oil, palm oil and palm kernel oil.

[0026] In a preferred embodiment, the synthetic ester is selected as a diester, triester, or tetraester synthesized from a polyol and fatty acids of different carbon chain lengths.

[0027] In a preferred embodiment, the synthetic ester is selected as a diester, triester, or tetraester synthesized from a polyol and fatty acids of different carbon chain lengths, wherein the carbon chain length of the fatty acid used to synthesize the synthetic ester is 12 to 20 carbon atoms.

[0028] In a preferred embodiment, the mineral oil is selected from paraffin-based minerals with a viscosity range of 30-100 cst at 40°C.

[0029] In a preferred embodiment, the extreme pressure anti-wear additive is a mixture of sulfur-containing extreme pressure anti-wear agent and phosphorus-containing extreme pressure anti-wear agent.

[0030] In a preferred embodiment, the sulfur-containing extreme pressure anti-wear agent is a sulfur ester or an alkyl polysulfide.

[0031] The phosphorus-containing extreme pressure anti-wear agent is an alkyl phosphate ester or a thiophosphate amine salt.

[0032] In a preferred embodiment, the antioxidant is an aromatic amine type or a phenolic amine type antioxidant.

[0033] In a preferred embodiment, the emulsifier is selected from polyoxyethylene alkylamine, fatty alcohol polyoxyethylene ether, or high molecular weight polyether emulsifier.

[0034] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides a method for preparing a rolling compound for Hi-B steel, characterized by comprising the following steps:

[0035] Step S1001: Natural oils, synthetic esters and mineral oils are added to the container in sequence;

[0036] Step S1002: Add the antioxidant to the above container and stir evenly until the antioxidant is completely dissolved;

[0037] Step S1003: Modified triazinon acid, extreme pressure anti-wear additive, and emulsifier are added sequentially to the above container and stirred evenly to obtain the rolling compound for Hi-B steel. The prepared rolling compound for Hi-B steel comprises the following components in weight percentage:

[0038] Modified triazine acid 1.5-3.0%;

[0039] Natural oils 30.0%–50.0%;

[0040] Synthetic esters 10.0%–30.0%

[0041] Mineral oil 20.0%–40.0%;

[0042] Extreme pressure anti-wear additive 2.0%–10.0%

[0043] Antioxidant 0.3-0.9%;

[0044] Emulsifier 0.8-3.5%.

[0045] According to a preferred embodiment of the present invention, the method for preparing the rolling compound for Hi-B steel needs to meet the following conditions:

[0046] In step S1002, after stirring until the antioxidant is completely dissolved, the temperature inside the container is raised to 70-80°C.

[0047] In step S1003, the temperature inside the container is adjusted to 48–57°C. Detailed Implementation

[0048] The preferred embodiments described below are merely examples, and other obvious variations will be apparent to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0049] A rolling mill for Hi-B steel according to a preferred embodiment of the present invention will be described in detail below, wherein the rolling mill for Hi-B steel comprises:

[0050] Modified triazine acid 1.5-3.0%;

[0051] Natural oils 30.0%–50.0%;

[0052] Synthetic esters 10.0%–30.0%

[0053] Mineral oil 20.0%–40.0%;

[0054] Extreme pressure anti-wear additive 2.0%–10.0%

[0055] Antioxidant 0.3-0.9%;

[0056] The emulsifier is 0.8-3.5%, wherein the modified triazine acid has the following structural formula:

[0057]

[0058] It is worth mentioning that modified triazine acid, by utilizing the thermal stability of amide and carboxylic acid groups, reduces the probability of their desorption from the silicon steel sheet surface under high-temperature conditions. Furthermore, the three functional groups of different polarities—ester, amide, and acid—exhibit a synergistic effect, forming a denser protective layer, thus providing excellent corrosion protection under high-temperature rolling conditions. In addition, modified triazine acid, through its larger molecular size and the synergistic adsorption of acid, amide, and ester bonds, forms a more efficient and robust adsorption film on the silicon steel surface, which not only provides corrosion protection but also excellent lubrication. This increases lubrication between the strip and the rolls, better protecting the work rolls and strip surface, and improving the sheet quality.

[0059] In addition, modified triazine acid is inexpensive, which greatly reduces the cost of rolling mills used in Hi-B steel; on the other hand, modified triazine acid is not easily soluble in water, making it easy to treat downstream wastewater.

[0060] In a preferred embodiment, the groups R1, R2, and R3 are derived from the alkyl portion of coconut oil acid, oleic acid, stearic acid, linoleic acid, lauric acid, ricinoleic acid, tall oil acid, or palmitoleic acid, respectively.

[0061] In a preferred embodiment, the groups R1, R2, and R3 may be the same or different.

[0062] m is derived from the alkyl portion of palmitoleic acid or stearic acid, and n is derived from the alkyl portion of oleic acid or lauric acid.

[0063] In a preferred embodiment, the natural oil is selected from one or a mixture of at least two of lard, coconut oil, palm oil and palm kernel oil.

[0064] In a preferred embodiment, the synthetic ester is selected as a diester, triester, or tetraester synthesized from a polyol and fatty acids of different carbon chain lengths.

[0065] In a preferred embodiment, the synthetic ester is selected as a diester, triester, or tetraester synthesized from a polyol and fatty acids of different carbon chain lengths, wherein the carbon chain length of the fatty acid used to synthesize the synthetic ester is 12 to 20 carbon atoms.

[0066] In a preferred embodiment, the mineral oil is selected from paraffin-based minerals with a viscosity range of 30-100 cst at 40°C.

[0067] In a preferred embodiment, the extreme pressure anti-wear additive is a mixture of sulfur-containing extreme pressure anti-wear agent and phosphorus-containing extreme pressure anti-wear agent.

[0068] In a preferred embodiment, the sulfur-containing extreme pressure anti-wear agent is a sulfur ester or an alkyl polysulfide.

[0069] The phosphorus-containing extreme pressure anti-wear agent is an alkyl phosphate ester or a thiophosphate amine salt.

[0070] In a preferred embodiment, the antioxidant is an aromatic amine type or a phenolic amine type antioxidant.

[0071] In a preferred embodiment, the emulsifier is selected from polyoxyethylene alkylamine, fatty alcohol polyoxyethylene ether, or high molecular weight polyether emulsifier.

[0072] Example 1:

[0073] A rolling compound for Hi-B steel, comprising the following components:

[0074]

[0075] Table 1

[0076] Example 2:

[0077] A rolling compound for Hi-B steel, comprising the following components:

[0078]

[0079] Table 2

[0080] In Tables 1 and 2, lard, palm kernel oil, palm oil, and coconut oil are natural oils; synthetic triesters and synthetic tetraesters are synthetic esters; the mineral oil selected is paraffin-based with a viscosity range of 30–100 cSt at 40°C; butylphenol and dimethylamino-p-cresol are antioxidants; ammonium phosphate, alkyl sulfides, oleyl alcohol phosphate, and sulfurized lard are extreme pressure anti-wear additives; polyoxyethylene ether and polyoxyethylene alkylamine are emulsifiers.

[0081] The rolling mill preparations for Hi-B steel in Examples 1 and 2 can be prepared according to the following production steps:

[0082] Step A: Add the natural oils and mineral oils to the container in sequence, and heat the container to 70-80°C;

[0083] Step B: Add the antioxidant to the container and stir evenly until the antioxidant is completely dissolved. Then adjust the temperature inside the container to 48-57°C.

[0084] Step C: Add the modified triazine, extreme pressure anti-wear additive, and emulsifier to the container in sequence, and stir until homogeneous to obtain the rolling compound for Hi-B steel.

[0085] The method of using the Hi-B steel rolling medium of the present invention involves dispersing the Hi-B steel rolling medium of the present invention in deionized water during the rolling process to form an emulsion system, and rolling is performed in the form of an emulsion. The mass concentration of the Hi-B steel rolling medium in the emulsion system is 2.0% to 4.0%.

[0086] Comparative example:

[0087] Two commercially available rolling media, A and B, for Hi-B steel were selected as comparative examples and their performance was compared with that of the embodiments. Both products have been in operation in the field for many years, but both suffer from problems such as surface corrosion, difficulty in cleaning, and high wastewater treatment costs.

[0088] The corrosion resistance performance of the finished products from Examples 1, 2, and Comparative Examples A and B was tested, and the test results are shown in the table below:

[0089] Corrosion resistance test:

[0090] To evaluate the corrosion resistance of Hi-B steel rolling media, a damp heat chamber test method was used to evaluate and compare the Hi-B steel rolling media of Examples 1 and 2 with comparable Hi-B steel rolling media of the same type in the market, Comparative Example A and Comparative Example B. The evaluation method adopted was GB-T2361.

[0091]

[0092] Table 3

[0093] As shown in Table 3, the corrosion resistance test results of the rolling compound for Hi-B steel of the present invention have a much longer corrosion resistance time than conventional Hi-B steel rolling oils on the market. This indicates that the oil film strength of the Hi-B steel rolling medium of the present invention is high, and the oil film formed in the roll gap area during high-temperature rolling is not easily broken, thus improving the corrosion resistance. This demonstrates that the Hi-B steel rolling medium of the present invention has strong corrosion resistance, reduces the quality problem of rust on the plate surface after rolling, and effectively reduces the product defect rate of steel mills.

[0094] Reciprocating friction test:

[0095] To evaluate the lubrication performance of Hi-B steel rolling media, a reciprocating friction tester was used to evaluate and compare the Hi-B steel rolling media of Examples 1 and 2 with comparable conventional Hi-B steel rolling media on the market, Comparative Examples A and B. The evaluation results are as follows:

[0096]

[0097] Table 4

[0098] As can be seen from the reciprocating friction test results in Table 4, compared with comparative examples A and B, the friction coefficients of Examples 1 and 2 are relatively low. This indicates that the rolling compound of the present invention for Hi-B steel can provide good lubrication during high-temperature rolling, effectively reduce rolling force, reduce quality problems such as strip breakage and scratches, and thus greatly improve production efficiency.

[0099] In summary, the rolling compound for Hi-B steel of the present invention can form a dense and high-temperature resistant protective film in the roll gap area, effectively reducing the transport capacity of water molecules, oxygen molecules, and electrons to the metal surface, improving the protection of the rolled silicon steel sheet, and significantly enhancing its corrosion resistance. Secondly, the dense protective film increases the lubrication between the strip and the rolls, reducing lubrication defects such as scratches and abrasions on the sheet surface during rolling, and improving the sheet quality. Finally, the modified triazinon acid is not easily soluble in water, making it easy to treat wastewater in subsequent processes.

[0100] This invention provides a method for preparing rolling flux for Hi-B steel, comprising the following steps:

[0101] Step S1001: Natural oils, synthetic esters and mineral oils are added to the container in sequence;

[0102] Step S1002: Add the antioxidant to the above container and stir evenly until the antioxidant is completely dissolved;

[0103] Step S1003: Modified triazinon acid, extreme pressure anti-wear additive, and emulsifier are added sequentially to the above container and stirred evenly to obtain the rolling compound for Hi-B steel. The prepared rolling compound for Hi-B steel comprises the following components in weight percentage:

[0104] Modified triazine acid 1.5-3.0%;

[0105] Natural oils 30.0%–50.0%;

[0106] Synthetic esters 10.0%–30.0%

[0107] Mineral oil 20.0%–40.0%;

[0108] Extreme pressure anti-wear additive 2.0%–10.0%

[0109] Antioxidant 0.3-0.9%;

[0110] Emulsifier 0.8-3.5%.

[0111] According to a preferred embodiment of the present invention, the method for preparing the rolling compound for Hi-B steel must meet the following conditions:

[0112] In step S1002, after stirring until the antioxidant is completely dissolved, the temperature inside the container is raised to 70-80°C.

[0113] In step S1003, the temperature inside the container is adjusted to 48–57°C.

[0114] Those skilled in the art should understand that the embodiments of the present invention described above are merely examples and do not limit the invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been shown and explained in the embodiments, and any modifications or variations of the implementation of the present invention may be made without departing from the stated principles.

Claims

1. A rolling compound for Hi-B steel, characterized in that, The rolling compound for Hi-B steel includes: Modified triazine acid 1.5-3.0%; Natural oils 30.0%–50.0%; Synthetic esters 10.0%–30.0% Mineral oil 20.0%–40.0%; Extreme pressure anti-wear additive 2.0%–10.0% Antioxidant 0.3-0.9%; The emulsifier is 0.8-3.5%, wherein the modified triazine acid has the following structural formula: ； Groups R1, R2, and R3 are derived from the alkyl portion of coconut oil acid, oleic acid, stearic acid, linoleic acid, lauric acid, ricinoleic acid, tall oil acid, or palm oil acid, respectively; the groups R1, R2, and R3 may be the same or different; m is derived from the alkyl portion of palm oil acid or stearic acid, and n is derived from the alkyl portion of oleic acid or lauric acid.

2. The rolling compound for Hi-B steel according to claim 1, characterized in that, The natural oil is selected from one or a mixture of at least two of the following: lard, coconut oil, palm oil, and palm kernel oil.

3. The rolling compound for Hi-B steel according to claim 1, characterized in that, The synthetic ester is selected from diesters, triesters or tetraesters synthesized from polyols and fatty acids of different carbon chain lengths, and the carbon chain length of the fatty acids used to synthesize the synthetic ester is 12 to 20 carbon atoms.

4. The rolling compound for Hi-B steel according to claim 1, characterized in that, The mineral oil is selected from paraffin-based minerals with a viscosity range of 30~100 cst at 40°C.

5. The rolling compound for Hi-B steel according to claim 1, characterized in that, The extreme pressure anti-wear additive is a mixture of sulfur-containing extreme pressure anti-wear agent and phosphorus-containing extreme pressure anti-wear agent; The sulfur-containing extreme pressure anti-wear agent is a sulfurized ester or an alkyl polysulfide; the phosphorus-containing extreme pressure anti-wear agent is an alkyl phosphate ester or a thiophosphate amine salt. The antioxidant is selected from aromatic amine or phenolic amine antioxidants; The emulsifier is selected from polyoxyethylene alkylamine, fatty alcohol polyoxyethylene ether, or high molecular weight polyether emulsifier.

6. A method for preparing the rolling compound for the Hi-B steel according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1001: Natural oils, synthetic esters and mineral oils are added to the container in sequence; Step S1002: Add the antioxidant to the above container and stir evenly until the antioxidant is completely dissolved; Step S1003: Modified triazinon acid, extreme pressure anti-wear additive, and emulsifier are added sequentially to the above container and stirred evenly to obtain the rolling compound for Hi-B steel. The prepared rolling compound for Hi-B steel comprises the following components in weight percentage: Modified triazine acid 1.5-3.0%; Natural oils 30.0%–50.0%; Synthetic esters 10.0%–30.0% Mineral oil 20.0%–40.0%; Extreme pressure anti-wear additive 2.0%–10.0% Antioxidant 0.3-0.9%; Emulsifier 0.8-3.5%.

7. The method for preparing the rolling compound for Hi-B steel according to claim 6, characterized in that, The preparation method of the rolling compound for Hi-B steel must meet the following conditions: In step S1002, after stirring until the antioxidant is completely dissolved, the temperature inside the container is raised to 70-80°C. In step S1003, the temperature inside the container is adjusted to 48–57°C.

Images