A cold rolling method for cold-rolled plain carbon substrate for food-grade metal packaging

Abstract

The present application relates to the technical field of cold rolling of steel plates, and specifically discloses a method for cold rolling cold-rolled ordinary carbon substrates for food-grade metal packaging. The method for cold rolling cold-rolled ordinary carbon substrates for food-grade metal packaging comprises the following steps: selecting an ordinary carbon substrate for pickling to obtain a pretreated ordinary carbon substrate; adjusting the emulsion concentration, lateral pulling amount, tension, and single-pass reduction to roll the pretreated ordinary carbon substrate; annealing the rolled ordinary carbon substrate; and leveling, shearing, and storing the annealed ordinary carbon substrate. The method for cold rolling cold-rolled ordinary carbon substrates for food-grade metal packaging of the present application has the advantages of simple process and improved quality of ordinary carbon substrates through the synergistic effect between the various steps.

Description

Technical Field

[0001] The present application relates to the technical field of cold rolling of steel plates, and in particular to a method for cold rolling a cold-rolled plain carbon substrate for food-grade metal packaging. Background Art

[0002] Cold-rolled carbon substrate is also called ordinary carbon structural steel cold-rolled plate, also called cold-rolled plate, commonly known as cold plate. Cold-rolled carbon substrate is made of ordinary carbon structural steel hot-rolled steel strip, which is further cold-rolled into a steel plate with a thickness of less than 4mm. Cold-rolled carbon substrate has high dimensional accuracy. Coupled with annealing treatment, its mechanical properties and process performance are better than hot-rolled thin steel plate. In many fields, especially in the field of home appliance manufacturing, it has gradually replaced hot-rolled thin steel plate.

[0003] In addition, cold-rolled plain carbon substrates have good performance, that is, through cold rolling, thinner and higher precision cold-rolled strips and steel plates can be obtained, with high flatness, high surface finish, easy coating and plating processing, many varieties and wide applications. At the same time, they have the characteristics of high stamping performance and low yield point. Therefore, cold-rolled plain carbon substrates have a wide range of uses, mainly used in automobiles, printed iron drums, construction, building materials, bicycles and other industries.

[0004] At present, the conventional carbon substrate needs to undergo 2-3 annealing processes during the cold rolling process, which is cumbersome and complex, and also affects the quality of the conventional carbon substrate. Summary of the Invention

[0005] In order to simplify the process and improve the quality of the plain carbon substrate, the present application provides a cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging.

[0006] In a first aspect, the present application provides a method for cold-rolling a cold-rolled plain carbon substrate for food-grade metal packaging, which adopts the following technical solution:

[0007] A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging, comprising the following steps:

[0008] S1: Select a general carbon substrate and perform pickling to obtain a pre-treated general carbon substrate;

[0009] S2: adjusting the emulsion concentration, lateral movement, tension, and single-pass reduction to roll the pre-treated carbon substrate; S3: annealing the rolled carbon substrate;

[0010] S4: Flatten, cut and store the annealed carbon substrate.

[0011] By adopting the above technical solution, the cold rolling method of cold-rolled plain carbon substrate for food-grade metal packaging of the present application, through the synergistic effect between each step, not only reduces the number of annealing times to 1, shortens the operation cycle, simplifies the process, and improves work efficiency, but also improves the tensile strength, yield strength and elongation of the plain carbon substrate, thereby improving the quality of the plain carbon substrate. Among them, the tensile strength of the plain carbon substrate is 603-635MPa, the yield strength is 585-620MPa, and the elongation is 6-12%.

[0012] Carrying out pickling pretreatment on the general carbon substrate can remove the oxide scale and rust on the surface of the general carbon substrate, and prevent other impurities on the general carbon substrate from affecting the quality of the rolled safe finished product in subsequent operations; then adjusting the concentration of the emulsion, the amount of transverse pulling and the tension of the rolling mill to improve the lubricity and facilitate the rolling of the general carbon substrate; the steel strip in the prior art usually needs to be annealed 2-3 times during the cold rolling process, which is costly and time-consuming. According to the above method, the process is adjusted to reduce the number of annealing times to 1, shortening the operation cycle, reducing the overall cost, improving production efficiency, and improving the quality of the general carbon substrate; finally, the general carbon substrate is leveled, sheared and stored, which can eliminate the yield platform of the general carbon substrate, facilitate the improvement of the general carbon substrate, and further contribute to improving the quality of the general carbon substrate.

[0013] Preferably, the specific process of pickling in step S1 is: adding microbubbles to the pickling solution, heating and heating, and washing the plain carbon substrate under ultrasound, wherein the pickling solution is a mixture of hydrochloric acid solution and corrosion inhibitor, and the weight ratio of hydrochloric acid solution to corrosion inhibitor is 1: (0.2-0.4).

[0014] Furthermore, the specific process of pickling in step S1 is as follows: adding microbubbles to the pickling solution, heating to a temperature of 20-40° C., and washing the plain carbon substrate under 1-3 MHz ultrasound for 10-20 minutes, wherein the pickling solution is a mixture of hydrochloric acid solution and corrosion inhibitor, and the weight ratio of hydrochloric acid solution to corrosion inhibitor is 1:(0.2-0.4);

[0015] The diameter of the microbubbles is 100-200 μm, and the mass fraction of the hydrochloric acid solution is 20-30%.

[0016] By adopting the above technical solution, the specific pickling process is defined. First, microbubbles are added to the pickling solution. During the pickling process, the bubbles will explode on the surface of the carbon substrate, thereby impacting the impurities on the surface of the carbon substrate, which is more conducive to the removal of impurities on the surface of the carbon substrate. Then, the pickling solution is washed under the action of ultrasound. The ultrasonic vibration can make the pickling solution penetrate into the impurities on the surface of the carbon substrate, accelerating the removal of impurities. The pickling solution is composed of hydrochloric acid solution and corrosion inhibitor. The hydrochloric acid solution can corrode the impurities on the surface of the carbon substrate, thereby achieving the purpose of removing impurities. The corrosion inhibitor can protect the carbon substrate and reduce the chance of corrosion, achieving the purpose of removing impurities and protecting the carbon substrate, thereby improving the quality of the carbon substrate.

[0017] Preferably, the concentration of the emulsion in step S2 is 3.0%, the lateral displacement is 10 mm, the tension is 150-180 kg, and the single-pass reduction is 18-35%.

[0018] By adopting the above technical solution, the emulsion concentration, lateral movement, tension, and single-pass reduction are limited. By adjusting the above parameters, the number of annealing times is reduced to 1, shortening the operation cycle, reducing production costs, and improving production efficiency.

[0019] Preferably, in step S3, the plain carbon substrate is degreased before annealing.

[0020] Preferably, the specific process of the degreasing treatment is as follows: placing the rolled carbon substrate into the degreasing solution, soaking it at a temperature of 40-60°C for 2-4 minutes, washing it for 1-3 minutes at a swing frequency of 20-40 times / min, 1 round trip, and a swing distance of 40-60mm, taking out the carbon substrate, soaking it in water for 3-5 times, and completing the degreasing after drying.

[0021] By adopting the above technical solution, there is lubricating oil on the surface of the plain carbon substrate during the rolling process. During the rolling process, the oil evaporates and leaves black spots on the plain carbon substrate. The plain carbon substrate before annealing is degreased to remove the black spots on the surface of the plain carbon substrate. Moreover, through the dual effects of soaking in the degreasing liquid and washing with a swing, the degreasing liquid can better play a saponification role and react with the black spots on the plain carbon substrate. The washing vibration is more conducive to the removal of the saponified substances, thereby improving the quality of the plain carbon substrate.

[0022] Preferably, the degreasing solution comprises the following raw materials in parts by weight: 70-85 parts of water, 1-5 parts of sodium hydroxide, 0.1-0.5 parts of dodecylphenol polyoxyethylene ether, and 5-12 parts of sodium silicate.

[0023] By adopting the above technical solution, the raw materials of the degreasing solution are limited, which is more conducive to improving the removal rate of black spots on the general carbon substrate. Specifically, sodium hydroxide is a strong base, which can ionize OH after dissolving in water. - , can undergo saponification reaction, dissolve grease deposits, and form water-soluble sodium stearate and glycerin, thereby removing black spots on ordinary carbon substrates and improving the quality of ordinary carbon substrates; dodecylphenol polyoxyethylene ether can emulsify and disperse black spots, thereby separating the black spots from the surface of the ordinary carbon substrate and causing no damage to the ordinary carbon substrate; sodium silicate can not only inhibit the corrosion of ordinary carbon substrates, but also play a good detergent role with dodecylphenol polyoxyethylene ether, thereby further improving the removal rate of black spots and improving the quality of ordinary carbon substrates.

[0024] Preferably, the specific process of annealing in step S3 is as follows: the first heating stage is to 400-500°C, keeping warm for 2-3 hours, the second heating stage is to 650-720°C, the heating rate is 40-60°C / h, keeping warm for 10-14 hours, and cooling.

[0025] By adopting the above technical solution, the specific annealing process is limited, which facilitates the forming of the general carbon substrate, helps to shorten the operation cycle, improve production efficiency, and improve the quality of the general carbon substrate.

[0026] As a preference: during the insulation stage, protective gas is introduced for protection, and the protective gas flow rate is 4-6m 3 / h, the protective gas is a mixture of nitrogen and helium, and the weight ratio of nitrogen to helium is 1:1.

[0027] By adopting the above technical solution, protective gas is filled in during the heat preservation stage of the annealing process for protection, which facilitates the continuous progress of the annealing process and shortens the operation cycle. In addition, nitrogen and helium are both inert gases with good stability and will not affect the general carbon substrate. Nitrogen is easier to obtain than helium. Selecting nitrogen and helium as protective gases facilitates the general carbon substrate to better complete the annealing process and improve the quality of the general carbon substrate.

[0028] Preferably, the specific process of leveling in step S4 is: leveling is performed at a temperature of 30-50° C. and a leveling liquid with a concentration of 1-2%.

[0029] Furthermore, the specific process of leveling in step S4 is: leveling at a temperature of 30-50° C. and a leveling liquid with a concentration of 1-2%;

[0030] The leveling liquid comprises 0.5-1.5% EDTA, 5-15% silicone oil, 10-20% nonylphenol polyoxyethylene ether, 5-15% triethanolamine, and the balance is water.

[0031] By adopting the above technical solution and limiting the leveling process, the yield platform of the general carbon substrate can be eliminated, which facilitates the final improvement of the general carbon substrate and improves the quality of the general carbon substrate.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] 1. Since the present application adopts the process of pretreatment-rolling-annealing-leveling, shearing and warehousing of the general carbon substrate for cold rolling, the general carbon substrate is first pretreated by pickling to prevent other impurities on the general carbon substrate from affecting the quality of the rolled safe finished product in subsequent operations; then the concentration of the emulsion, the lateral pulling amount and the tension of the rolling mill are adjusted to improve the lubricity and facilitate the rolling of the general carbon substrate; the number of annealing times is reduced to 1, which shortens the operation cycle, reduces the overall cost, improves production efficiency, and improves the quality of the general carbon substrate; finally, the general carbon substrate is leveled, sheared and stored, which can eliminate the yield platform of the general carbon substrate, facilitate the improvement of the general carbon substrate, and further contribute to improving the quality of the general carbon substrate, so that the tensile strength of the general carbon substrate can reach 635MPa, the yield strength can reach 620MPa, and the elongation can reach 12%.

[0034] 2. In this application, it is preferred to degrease the plain carbon substrate before annealing. Black spots will be left on the plain carbon substrate during the rolling process. Degreasing can remove the black spots on the surface of the plain carbon substrate. The dual effects of soaking in the degreasing liquid and washing with a swing can enable the degreasing liquid to better play a saponification role and react with the black spots on the plain carbon substrate. The swing washing vibration is more conducive to the removal of the saponified substances, thereby improving the quality of the plain carbon substrate. DETAILED DESCRIPTION

[0035] The following is a further detailed description of this application in conjunction with the specific content.

[0036] raw material

[0037] The corrosion inhibitor is SH-406 corrosion inhibitor; the molecular weight of dodecylphenol polyoxyethylene ether is 702; and the molecular weight of nonylphenol polyoxyethylene ether is 308.

[0038] Preparation Example

[0039] Preparation Example 1

[0040] A degreasing solution is prepared by the following method, and the raw material ratio is shown in Table 1:

[0041] Mix water, sodium hydroxide, dodecylphenol polyoxyethylene ether and sodium silicate evenly to obtain a degreasing solution.

[0042] Preparation Example 2-3

[0043] A degreasing solution is prepared in accordance with Preparation Example 1, which differs from Preparation Example 1 in that the raw material ratios of the degreasing solution are different. The raw material ratios are shown in Table 1.

[0044] Table 1 Raw materials of degreasing solution in different preparation examples

[0045]

[0046]

[0047] Example

[0048] Example 1

[0049] A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging, comprising the following steps:

[0050] S1: adding microbubbles with a diameter of 150 μm to an acid cleaning solution, heating to 30°C, and washing the carbon substrate under 2 MHz ultrasonic waves for 15 minutes to obtain a pretreated carbon substrate; wherein the acid cleaning solution is a mixture of 2 kg of 25% hydrochloric acid solution and 0.4 kg of SH-406 corrosion inhibitor;

[0051] S2: The concentration of the emulsion is adjusted to 3.0%, the lateral displacement is 10 mm, the tension is 165 kg, the single-pass reduction is 26%, and the pre-treated plain carbon substrate is rolled;

[0052] S3: Degreasing the plain carbon substrate before annealing: Place the rolled plain carbon substrate into the degreasing solution prepared in Preparation Example 1, soak at 50°C for 3 minutes, and wash for 2 minutes at a swing frequency of 30 times / min, 1 round trip, and a swing distance of 50 mm. Remove the plain carbon substrate, soak it in water 5 times, and dry it to complete degreasing.

[0053] Annealing of the degreased carbon substrate was carried out as follows: the first heating stage was to 450°C, kept warm for 2.5h, the second heating stage was to 680°C, the heating rate was 50°C / h, kept warm for 12h, and cooled; the air flow rate during the holding stage was 5m 3 / h of protective gas for protection, the protective gas is a mixture of nitrogen and helium, and the weight ratio of nitrogen to helium is 1:1;

[0054] S4: The annealed carbon substrate is leveled at 40°C in a leveling solution with a concentration of 1.5%, and then the carbon substrate is sheared and stored. The leveling solution contains 1% EDTA, 10% silicone oil, 15% nonylphenol polyoxyethylene ether, 10% triethanolamine, and the balance is water.

[0055] Example 2

[0056] A method for cold-rolling a cold-rolled plain carbon substrate for food-grade metal packaging is provided. The method differs from Example 1 in that the amount of corrosion inhibitor added to the pickling solution in step S1 is different. The amount of corrosion inhibitor added to the pickling solution in Example 2 is 0.6 kg.

[0057] Example 3

[0058] A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging is provided, which differs from Example 1 in that the amount of corrosion inhibitor added to the pickling solution in step S1 is different. In Example 3, the amount of corrosion inhibitor added to the pickling solution is 0.8 kg.

[0059] Example 4

[0060] A method for cold-rolling a cold-rolled plain carbon substrate for food-grade metal packaging is disclosed. The method differs from Example 2 in that the source of the degreasing solution in step S3 is different. The degreasing solution in Example 4 is prepared using Preparation Example 2.

[0061] Example 5

[0062] A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging is disclosed. The method differs from Example 2 in that the source of the degreasing solution in step S3 is different. The degreasing solution in Example 5 is prepared using Preparation Example 3.

[0063] Comparative Example

[0064] Comparative Example 1

[0065] A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging, which differs from Example 1 in that the plain carbon substrate is not pickled.

[0066] Comparative Example 2

[0067] A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging, which differs from Example 1 in that the plain carbon substrate is not degreased.

[0068] Performance testing

[0069] The following performance tests were performed on the plain carbon substrates in Examples 1-5 and Comparative Examples 1-2:

[0070] Tensile strength: The tensile strength of the carbon substrate was measured according to GB / T228-1987 “Metal Tensile Test Methods”. The test results are shown in Table 2.

[0071] Yield strength: The yield strength of the carbon substrate was measured in accordance with GB / T228-2002 "Metallic Materials Room Temperature Tensile Test Methods". The test results are shown in Table 2.

[0072] Elongation: The elongation of the carbon substrate was measured according to GB / T228-2002 "Metallic Materials Room Temperature Tensile Test Method". The test results are shown in Table 2.

[0073] Table 2 Test results

[0074]

[0075] The cold-rolling method for cold-rolled common carbon substrate for food-grade metal packaging of the present application, through the synergistic effect between each step, not only reduces the number of annealing times to 1, shortens the operation cycle, simplifies the process, and improves work efficiency, but also improves the tensile strength, yield strength and elongation of the common carbon substrate, thereby improving the quality of the common carbon substrate. Among them, the tensile strength of the common carbon substrate is 603-635MPa, the yield strength is 585-620MPa, and the elongation is 6-12%.

[0076] Combining Example 1 and Comparative Example 1, it can be seen that the tensile strength of the common carbon substrate processed by the cold rolling method in Example 1 is 603 MPa, the yield strength is 585 MPa, and the elongation is 6%, which is better than Comparative Example 1, indicating that it is more appropriate to pre-treat the common carbon substrate with pickling. First, microbubbles are added to the pickling solution. During the pickling process, the bubbles will burst on the surface of the common carbon substrate, thereby impacting the impurities on the surface of the common carbon substrate, which is more conducive to the removal of impurities on the surface of the common carbon substrate; then, washing is carried out under the action of ultrasound. The vibration of the ultrasound can enable the pickling solution to penetrate into the impurities on the surface of the common carbon substrate, thereby accelerating the removal of impurities. The pickling solution is composed of a hydrochloric acid solution and a corrosion inhibitor. The hydrochloric acid solution can corrode the impurities on the surface of the common carbon substrate, thereby achieving the purpose of removing impurities. The corrosion inhibitor can protect the common carbon substrate and reduce the probability of corrosion, thereby achieving the purpose of removing impurities and protecting the common carbon substrate, thereby improving the quality of the common carbon substrate.

[0077] Combining Example 1 and Comparative Example 2, it can be seen that the tensile strength of the ordinary carbon substrate treated by the cold rolling method in Example 1 is 603 MPa, the yield strength is 585 MPa, and the elongation is 6%, which is better than Comparative Example 2, indicating that it is more appropriate to degrease the ordinary carbon substrate. Black spots will be left on the ordinary carbon substrate during the rolling process. Degreasing can remove the black spots on the surface of the ordinary carbon substrate, and through the dual effects of soaking in the degreasing liquid and washing, the degreasing liquid can better play a saponification role and react with the black spots on the ordinary carbon substrate. The washing vibration is more conducive to the removal of the saponified substances, thereby improving the quality of the ordinary carbon substrate.

[0078] In combination with Examples 1-3, it can be seen that the tensile strength of the ordinary carbon substrate treated by the cold rolling method in Example 2 is 618 MPa, the yield strength is 600 MPa, and the elongation is 10%, which are better than those of other examples. This shows that the weight ratio of the hydrochloric acid solution and the corrosion inhibitor in the pickling solution in Example 2 is more appropriate, which is more conducive to removing impurities on the ordinary carbon substrate, thereby improving the quality of the ordinary carbon substrate.

[0079] In combination with Example 2 and Examples 4-5, it can be seen that the tensile strength of the ordinary carbon substrate treated by the cold rolling method in Example 4 is 635 MPa, the yield strength is 620 MPa, and the elongation is 12%, which are better than those of other examples. This shows that the degreasing solution in Preparation Example 2 is more suitable, and the degreasing solution can better exert the saponification effect, which helps to remove black spots on the ordinary carbon substrate, thereby improving the quality of the ordinary carbon substrate.

[0080] The above-mentioned specific implementation examples are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging, characterized in that: The steps include: S1: Select a general carbon substrate and perform pickling to obtain a pre-treated general carbon substrate; S2: Adjust the emulsion concentration, lateral movement, tension, and single-pass reduction to roll the pre-treated plain carbon substrate; S3: annealing the rolled carbon substrate; S4: Flatten, cut and store the annealed carbon substrate; The step S3 degreases the carbon substrate before annealing. The specific process of the degreasing treatment is as follows: placing the rolled carbon substrate in a degreasing solution, soaking it at a temperature of 40-60°C for 2-4 minutes, washing it with a swing frequency of 20-40 times / min, 1 round trip, and a swing distance of 40-60mm for 1-3 minutes, taking out the carbon substrate, immersing it in water for 3-5 times, and drying it to complete the degreasing. The degreasing solution includes the following raw materials in parts by weight: 70-85 parts of water, 1-5 parts of sodium hydroxide, 0.1-0.5 parts of dodecylphenol polyoxyethylene ether, and 5-12 parts of sodium silicate; The specific process of annealing in step S3 is as follows: the first heating stage is to 400-500°C, keeping warm for 2-3 hours, the second heating stage is to 650-720°C, the heating rate is 40-60°C / h, keeping warm for 10-14 hours, and cooling.

2. The cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging according to claim 1, characterized in that: The specific process of pickling in step S1 is: adding microbubbles to the pickling solution, heating and raising the temperature, and washing the plain carbon substrate under ultrasonic waves, wherein the pickling solution is a mixture of hydrochloric acid solution and corrosion inhibitor, and the weight ratio of hydrochloric acid solution to corrosion inhibitor is 1: (0.2-0.4).

3. The cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging according to claim 1, characterized in that: The concentration of the emulsion in step S2 is 3.0%, the lateral displacement is 10 mm, the tension is 150-180 kg, and the single-pass reduction is 18-35%.

4. The method for cold-rolling a cold-rolled plain carbon substrate for food-grade metal packaging according to claim 1, characterized in that: During the insulation stage, protective gas is introduced for protection. The protective gas flow rate is 4-6m3 / h. The protective gas is a mixture of nitrogen and helium, and the weight ratio of nitrogen to helium is 1:

1.

5. The cold rolling method for a cold-rolled plain carbon substrate for food-grade metal packaging according to claim 1, characterized in that: The specific process of leveling in step S4 is: leveling is performed at a temperature of 30-50° C. and a leveling liquid with a concentration of 1-2%.

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