A production method for solving blistering of double zero aluminum foil during annealing

Abstract

The present invention discloses a production method for solving the blistering of double-zero aluminum foil annealing, comprising the following steps: S1, in the aluminum foil rolling process, controlling the aluminum foil flatness of the intermediate rolling pass and the finished product rolling pass; S2, when rolling the finished product pass, controlling the residual rolling oil amount on the aluminum foil surface to ≤17mg / m 2 ; S3, when slitting and coiling, control the coiling density of the slitting aluminum foil coil to be 2.32-2.46g / cm³; S4, during the annealing process, first heat from room temperature to 70-90°C, then keep warm for 12-24h; then heat to annealing temperature for annealing, and the heating rate should be controlled at 3-15°C / h. The method of the present invention can effectively control the volatilization of rolling oil during the annealing process, solve the problem of extrusion deformation of aluminum foil caused by the huge pressure generated by the gasification of rolling oil, and can significantly improve the quality and performance of double-zero aluminum foil.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-thin aluminum alloy foil production, and in particular to a production method for solving blistering during annealing of double-zero aluminum foil. Background Art

[0002] As a lightweight, high-strength, environmentally friendly, non-toxic, odorless, and recyclable material, double-zero aluminum foil has good sealing, waterproof, light-proof, and oxygen-proof properties, and is widely used in the packaging of food, medicine, and electronic devices. At present, domestic and foreign aluminum foils, especially double-zero aluminum foil products, mainly use 1000 and 8000 series aluminum alloys (such as 1235, 8111, 8079, etc. alloys), and are used in food fields such as milk, beverages, drinks, and solid foods, pharmaceutical packaging fields such as capsules, tablets, and syringes, as well as packaging, heat insulation, and construction of electronic components.

[0003] At present, there are usually two production process routes for double zero aluminum foil: one is "using hot rolled billet - cold rolling - foil rolling - slitting - annealing - packaging" production process route, and the other is "using cast rolled billet - cold rolling - foil rolling - slitting - annealing - packaging" production process route. The finished aluminum foil produced under the two process routes will have "bubbles" on both sides of the aluminum foil roll to varying degrees when used in the composite process, which is called "annealing blistering" in the industry (see the attached picture for blistering). Figure 2 Left picture, because the aluminum foil is very bright, it is not easy to observe), mainly appears on the outer layer of the aluminum foil roll, and the thinner the aluminum foil, the more obvious the phenomenon. This annealing blister will appear wrinkled during the composite process with other materials, seriously affecting product quality and customer experience.

[0004] After a lot of research, it was found that during the rolling process, a layer of rolling oil film will remain on the surface of the aluminum foil; during the slitting process, the aluminum foil will be cut into single aluminum foil rolls according to a certain winding density, and there will be a certain gap between the layers of the aluminum foil, and this gap is filled with residual rolling oil from the rolling process; during annealing and heating, the rolling oil can only evaporate from the end face of the aluminum foil roll through the gap between the layers. However, the gap between the layers is not a flat gap, but more like a porous structure. The surface roughness of the aluminum foil is generally 0.15-0.35μm, and the gap between the layers of the aluminum foil is also <1μm after measurement and calculation. Therefore, the gap between the layers is staggered at the microscopic level (see Appendix Figure 1), which makes the diffusion path of oil and gas very complicated. During the annealing and heating process, especially after rapid heating, the volume of the oil film expands rapidly and becomes an oil and gas mass, which will generate huge pressure; but after the rolling oil becomes gaseous, it cannot evaporate smoothly from the gap, but squeezes out of the gap in the form of "extrusion". At this time, the aluminum foil is squeezed and deformed, forming a blistering phenomenon. Therefore, there are many factors that affect annealing blistering, such as the rolling plate shape, the residual amount of rolling oil on the surface of the finished aluminum foil, the slitting and coiling density, and the annealing heating rate.

[0005] In order to solve the problem of blistering during annealing of double zero aluminum foil, the aluminum foil industry generally controls it by peeling off the outer layer of aluminum foil rolls. However, this method can neither completely eliminate annealing blistering nor cause great waste. Therefore, a new and effective production method is needed to solve the problem of blistering during annealing of double zero aluminum foil. At present, there is no report on the method of solving the blistering during annealing of double zero aluminum foil by controlling the aluminum foil production process. Summary of the invention

[0006] In the production process of aluminum foil, whether hot-rolled billet or cast-rolled billet is used, foil rolling, slitting and annealing must be performed after cold rolling, and finally packaged as a finished product. In order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a production method for solving the blistering of double-zero aluminum foil annealing, so as to improve the quality and performance of double-zero aluminum foil.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A production method for solving the blistering of double zero aluminum foil annealing of the present invention comprises the following steps:

[0009] S1, during the aluminum foil rolling process, controls the flatness of the aluminum foil in the intermediate rolling pass and the finished rolling pass;

[0010] S2, when rolling the finished product, control the residual rolling oil on the surface of the aluminum foil to ≤17mg / m 2 ;

[0011] S3, when slitting and coiling, control the coiling density of the slitting aluminum foil coil to be between 2.32 and 2.46 g / cm³;

[0012] S4, during the annealing process, first raise the temperature from room temperature to 70-90°C, then keep it at this temperature for 12-24h; then raise the temperature to the annealing temperature for annealing, and the heating rate should be controlled at 3-15°C / h.

[0013] In the aluminum alloy plate and strip processing industry, the indicator for evaluating the plate quality is expressed as "straightness". In order to control the aluminum foil to have good straightness, the aluminum foil will be divided into four positions along the width direction according to the principle of symmetry for control during the actual processing, namely, the plate shape one, plate shape two, plate shape three, plate shape four (see Plate shape setting Figure 3 ). Flatness 1 refers to the flatness value of the middle position in the width direction of the aluminum foil. A positive value indicates that the middle is loose, and a negative value indicates that the middle is tight. Flatness 2 refers to the flatness inclination value of the two sides in the width direction of the aluminum foil. A positive value indicates that the operating side is tighter than the transmission side, and a negative value indicates that the operating side is looser than the transmission side. Flatness 3 refers to the flatness index of the two sides of the aluminum foil along the width direction. A positive value indicates that the two sides are tight, and a negative value indicates that the two sides are loose. Flatness 4 refers to the flatness value of the second rib position in the width direction of the aluminum foil. A positive value indicates that the second rib is loose, and a negative value indicates that the second rib is tight.

[0014] The unit of straightness is "I", that is, 1 "I" unit is defined as the straightness error caused by 0.001% or 1 / 100000 of the difference in length of different fibers in the strip. In other words, if a 1000mm long strip is rolled and the length of its edge is 1000.01mm, the straightness error between the center and the edge will be 1 "I" unit. Preferably, the straightness setting of the intermediate rolling pass is: plate shape one is -12I to -2I, plate shape two is 0I, plate shape three is -4I to -1I, and plate shape four is 0I; the straightness setting of the finished rolling pass is: plate shape one is -28I to -12I, plate shape two is 0I, plate shape three is -6I to -2I, and plate shape four is 0I; the shape of the finished aluminum foil is measured on an offline shape meter, and the control range of the sag on both sides is -8 to -2mm.

[0015] Preferably, in order to control the amount of rolling oil remaining on the surface of the aluminum foil, in step S2, the surface purge pressure of the outlet aluminum foil of the finished rolling pass can be set to 0.2-0.5 MPa to purge away the excess rolling oil.

[0016] In this industry, the coiling density = actual coil weight / actual volume. Since there are gaps between layers, the coiling density will be lower than the metal density of the aluminum foil. If the coiling density is too large, it will be unfavorable for the volatilization of the rolling oil and will more easily cause annealing blistering. If the coiling density is too small, the aluminum foil roll will be unstable and prone to misalignment or pitting. Preferably, in order to accurately control the coiling density of the slit aluminum foil roll, it is necessary to control the coiling tension to 22-40MPa, the support roller pressure to 2.0-3.0N / mm, the flattening roller pressure to 1.0-2.0N / mm, and the surface tension to 1-10MPa.

[0017] The aluminum foil roll of the present invention is kept warm at 70-90°C for 12-24h before formal annealing, because at this temperature, the rolling oil at the edge of the aluminum foil can be partially volatilized, and the strength of the aluminum foil has not decreased at this temperature, and the rolling oil will not cause deformation of the aluminum foil during the volatilization process. Preferably, during the annealing process, the heating rate of each heating stage should be controlled: the heating rate of 0.007-0.009mm aluminum foil is 10-15°C / h; the heating rate of 0.0058-0.007mm aluminum foil is 6-10°C / h; the heating rate of 0.0045-0.0058mm aluminum foil is 3-6°C / h.

[0018] Compared with the prior art, the present invention has the following positive effects:

[0019] The method of the present invention can effectively control the volatilization of rolling oil in the annealing process, solve the problem of extrusion deformation of aluminum foil caused by the huge pressure generated by the gasification of rolling oil, and can significantly improve the quality and performance of double-zero aluminum foil: through precise plate shape control, the "cloth bag tied mouth" effect formed by the tight edges of the aluminum foil roll during the winding process is improved, so that the aluminum foil rolling oil is easier to volatilize without generating huge pressure inside the aluminum foil roll; strict surface residual oil control reduces the pressure generated by the gasification of residual rolling oil; reasonable slitting and coiling density control helps to maintain the structural stability of the aluminum foil, which is beneficial to the volatilization of rolling oil from the middle to the end surface of the aluminum foil roll; precise rolling oil volatilization control allows a part of the rolling oil on both sides of the aluminum foil roll to evaporate first before the performance of the aluminum foil is reduced, which is beneficial to the pressure stability of the subsequent rolling oil volatilization process from the inside of the roll to the outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a microscopic diagram of the layers of an aluminum foil roll.

[0021] Figure 2 It is the annealing blister that occurs in aluminum foil coils produced by conventional production methods.

[0022] Figure 3 It is a schematic diagram of plate flatness and its setting. DETAILED DESCRIPTION

[0023] The present invention is further described below by means of specific embodiments, which are only used to illustrate the present invention rather than to limit the present invention.

[0024] Example 1

[0025] Aluminum foil with a thickness of 0.006 mm and a width of 1626 mm is produced by using cast and rolled 8079 aluminum alloy. The production is carried out according to "cold rolling - foil rolling - slitting - annealing - packaging". The production method for solving the blistering of double-zero aluminum foil annealing is adopted, including the following steps:

[0026] S1, during the foil rolling process, the straightness of the aluminum foil shape of the intermediate rolling pass and the finished rolling pass is controlled: the straightness of the intermediate rolling pass is set as: shape one is -8I, shape two is 0I, shape three is -2I, shape four is 0I; the straightness of the finished rolling pass is set as: shape one is -18I, shape two is 0I, shape three is -3I, shape four is 0I; after the aluminum foil is rolled in the finished pass, the shape is measured on the offline shape meter, and the sag on both sides is -4.2mm.

[0027] S2, when the aluminum foil is rolled into finished products, the surface purge pressure of the outlet aluminum foil is set to 0.32MPa. The residual oil on the surface of the rolled aluminum foil is measured, and the residual rolling oil on the surface of the aluminum foil is controlled to be 13.8mg / m 2 .

[0028] S3, the finished rolled aluminum foil roll is moved to the slitting machine for slitting. The winding tension is set to 30MPa, the support roller pressure is 2.4N / mm, the flattening roller pressure is 1.5N / mm, and the surface tension is 6MPa during the slitting process; the density of the aluminum foil roll after slitting is measured in real time, and the actual winding density of the aluminum foil roll is 2.43g / cm³.

[0029] S4, the slit aluminum foil roll is loaded into the annealing furnace, and the heating rate is set to 7.5℃ / h. The temperature is first raised from room temperature to 80℃, and then kept at this temperature for 16 hours; then the temperature is raised to the annealing temperature at the same heating rate, and annealing is performed according to the conventional process until the annealing is completed.

[0030] The annealed aluminum foil coil was moved to the rewinding machine for rewinding inspection. No annealing blistering occurred and the quality was good.

[0031] Comparative Example 1

[0032] Comparative Example 1 is a comparative example of Example 1, except that in S3, the finished rolled aluminum foil coil is moved to a slitting machine for slitting, and the coiling tension is set to 43 MPa, the support roller pressure is 3.2 N / mm, the flattening roller pressure is 2.5 N / mm, and the surface tension is 6 MPa during the slitting process; the density of the aluminum foil coil after slitting is measured in real time, and the actual coiling density is 2.53 g / cm³.

[0033] The aluminum foil coil that has completed annealing was moved to the rewinding machine for rewinding inspection. Within 1000 meters of the outer circle of the rewinding, intermittent annealing blistering occurred 39 times, and the annealing blister quality problem was not solved.

[0034] Example 2

[0035] Hot-rolled 8079 aluminum alloy is used to produce aluminum foil with a thickness of 0.0055 mm and a width of 1460 mm. The production is carried out according to "cold rolling - foil rolling - slitting - annealing - packaging". The production method for solving the blistering of double-zero aluminum foil annealing is adopted, including the following steps:

[0036] S1, during the foil rolling process, the straightness of the aluminum foil shape of the intermediate rolling pass and the finished rolling pass is controlled: the straightness of the intermediate rolling pass is set as: shape one is -9I, shape two is 0I, shape three is -2I, shape four is 0I; the straightness of the finished rolling pass is set as: shape one is -20I, shape two is 0I, shape three is -3I, shape four is 0I; after the aluminum foil is rolled in the finished pass, the shape is measured on the offline shape meter, and the sag on both sides is -4.7mm.

[0037] S2, when the aluminum foil is rolled into finished products, the surface purge pressure of the outlet aluminum foil is set to 0.28MPa. The surface residual oil of the rolled aluminum foil is measured and the residual rolling oil on the surface of the aluminum foil is controlled to be 15.2mg / m 2 .

[0038] S3, the finished rolled aluminum foil roll is moved to the slitting machine for slitting. The winding tension is set to 33MPa, the support roller pressure is 2.4N / mm, the flattening roller pressure is 1.5N / mm, and the surface tension is 6MPa during the slitting process; the density of the aluminum foil roll after slitting is measured in real time, and the actual winding density of the aluminum foil roll is 2.41g / cm³.

[0039] S4, the slit aluminum foil roll is loaded into the annealing furnace, and the heating rate is set to 5.0℃ / h. The temperature is first raised from room temperature to 80℃, and then kept at this temperature for 16 hours; then the temperature is raised to the annealing temperature at the same heating rate, and annealing is performed according to the conventional process until the annealing is completed.

[0040] The annealed aluminum foil coil was moved to the rewinding machine for rewinding inspection. No annealing blistering occurred and the quality was good.

[0041] Comparative Example 2

[0042] Comparative Example 2 is a comparative example of Example 2, except that in S2, when the aluminum foil is rolled into a finished product, the surface purge pressure of the outlet aluminum foil is set to 0.18 MPa. The residual oil on the surface of the rolled aluminum foil is measured, and the residual rolling oil on the surface of the aluminum foil is controlled to be 21.4 mg / m 2 ; The actual aluminum foil roll winding density is 2.40g / cm³.

[0043] The aluminum foil coil that has completed annealing was moved to the rewinding machine for rewinding inspection. Within 1000 meters of the outer circle of the rewinding, intermittent annealing blistering occurred 57 times, and the annealing blister quality problem was not solved.

[0044] Example 3

[0045] Aluminum foil with a thickness of 0.0053 mm and a width of 1240 mm is produced by using cast and rolled 8079 aluminum alloy. The production is carried out according to "cold rolling - foil rolling - slitting - annealing - packaging". The production method for solving the blistering of double-zero aluminum foil annealing is adopted, including the following steps:

[0046] S1, during the foil rolling process, the straightness of the aluminum foil shape of the intermediate rolling pass and the finished rolling pass is controlled: the straightness of the intermediate rolling pass is set as: shape one is -6I, shape two is 0I, shape three is -2I, shape four is 0I; the straightness of the finished rolling pass is set as: shape one is -16I, shape two is 0I, shape three is -4I, shape four is 0I; after the aluminum foil is rolled in the finished pass, the shape is measured on the offline shape meter, and the sagging amount on both sides is -3.1mm.

[0047] S2, when the aluminum foil is rolled into finished products, the surface purge pressure of the outlet aluminum foil is set to 0.3MPa. The residual oil on the surface of the rolled aluminum foil is measured, and the residual rolling oil on the surface of the aluminum foil is controlled to be 14.2mg / m 2 .

[0048] S3, the finished rolled aluminum foil roll is moved to the slitting machine for slitting. The winding tension is set to 34MPa, the support roller pressure is 2.4N / mm, the flattening roller pressure is 1.5N / mm, and the surface tension is 6MPa during the slitting process. The density of the aluminum foil roll after slitting is measured in real time, and the actual winding density of the aluminum foil roll is 2.42g / cm³.

[0049] S4, the slit aluminum foil roll is loaded into the annealing furnace, and the heating rate is set to 5.0℃ / h. The temperature is first raised from room temperature to 80℃, and then kept at this temperature for 16 hours; then the temperature is raised to the annealing temperature at the same heating rate, and annealing is performed according to the conventional process until the annealing is completed.

[0050] The annealed aluminum foil coil was moved to the rewinding machine for rewinding inspection. No annealing blistering occurred and the quality was good.

[0051] Comparative Example 3

[0052] Comparative Example 3 is a comparative example of Example 3, except that:

[0053] S1, during the foil rolling process, the straightness of the aluminum foil shape of the intermediate rolling pass and the finished rolling pass is controlled: the straightness of the intermediate rolling pass is set as: shape one is -6I, shape two is 0I, shape three is -2I, shape four is 0I; the straightness of the finished rolling pass is set as: shape one is -10I, shape two is 0I, shape three is 0I, shape four is 0I; after the aluminum foil is rolled in the finished pass, the shape is measured on the offline shape meter, and the sagging amount on both sides is -3.1mm.

[0054] S3, the finished rolled aluminum foil roll is moved to the slitting machine for slitting. The winding tension is set to 43MPa, the support roller pressure is 3.2N / mm, the flattening roller pressure is 2.5N / mm, and the surface tension is 6MPa during the slitting process; the density of the aluminum foil roll after slitting is measured in real time, and the actual winding density is 2.52g / cm³.

[0055] The aluminum foil coil that has completed annealing was moved to the rewinding machine for rewinding inspection. Within 1000 meters of the outer circle of the rewinding, intermittent annealing blistering occurred 74 times, and the annealing blister quality problem was not solved.

[0056] Example 4

[0057] Hot-rolled 8079 aluminum alloy is used to produce aluminum foil with a thickness of 0.009 mm and a width of 1510 mm. The production is carried out according to "cold rolling - foil rolling - slitting - annealing - packaging". The production method for solving the blistering of double-zero aluminum foil annealing is adopted, including the following steps:

[0058] S1, during the foil rolling process, the straightness of the aluminum foil shape of the intermediate rolling pass and the finished rolling pass is controlled: the straightness of the intermediate rolling pass is set as: shape one is -7I, shape two is 0I, shape three is -3I, shape four is 0I; the straightness of the finished rolling pass is set as: shape one is -19I, shape two is 0I, shape three is -3I, shape four is 0I; after the aluminum foil is rolled in the finished pass, the shape is measured on the offline shape meter, and the sag on both sides is -4.3mm.

[0059] S2, when the aluminum foil is rolled into finished products, the surface purge pressure of the outlet aluminum foil is set to 0.32MPa. The residual oil on the surface of the rolled aluminum foil is measured, and the residual rolling oil on the surface of the aluminum foil is controlled to be 14.3mg / m 2 .

[0060] S3, the finished rolled aluminum foil roll is moved to the slitting machine for slitting. The winding tension is set to 28MPa, the support roller pressure is 2.5N / mm, the flattening roller pressure is 1.4N / mm, and the surface tension is 7MPa during the slitting process; the density of the aluminum foil roll after slitting is measured in real time, and the actual winding density of the aluminum foil roll is 2.42g / cm³.

[0061] S4, the slit aluminum foil roll is loaded into the annealing furnace, and the heating rate is set to 12.0℃ / h. The temperature is first raised from room temperature to 80℃, and then kept at this temperature for 18 hours; then the temperature is raised to the annealing temperature at the same heating rate, and annealing is performed according to the conventional process until the annealing is completed.

[0062] The annealed aluminum foil coil was moved to the rewinding machine for rewinding inspection. No annealing blistering occurred and the quality was good.

[0063] Comparative Example 4

[0064] Comparative Example 4 is a comparative example of Example 4, except that:

[0065] S1, during the foil rolling process, the straightness of the aluminum foil shape of the intermediate rolling pass and the finished rolling pass is controlled: the straightness of the intermediate rolling pass is set as: shape one is -7I, shape two is 0I, shape three is -3I, shape four is 0I; the straightness of the finished rolling pass is set as: shape one is -9I, shape two is 0I, shape three is -1I, shape four is 0I; after the aluminum foil is rolled in the finished pass, the shape is measured on the offline shape meter, and the sagging amount on both sides is -1.2mm.

[0066] S4, the slit aluminum foil roll is loaded into the annealing furnace, and the heating rate is set to 17.0℃ / h. The temperature is first raised from room temperature to 80℃, and then kept at this temperature for 10 hours; then the temperature is raised to the annealing temperature at the same heating rate, and annealing is performed according to the conventional process until the annealing is completed.

[0067] The aluminum foil coil that has completed annealing was moved to the rewinding machine for rewinding inspection. Within 1000 meters of the outer circle of the rewinding, intermittent annealing blistering occurred 44 times, and the annealing blister quality problem was not solved.

Claims

1. A production method for solving the blistering of double zero aluminum foil annealing, characterized in that: The following steps are involved: S1, during the aluminum foil rolling process, controls the flatness of the aluminum foil in the intermediate rolling pass and the finished rolling pass; S2, when rolling the finished product, control the residual rolling oil on the surface of the aluminum foil to ≤17mg / m 2 ; S3, when slitting and coiling, control the coiling density of the slitting aluminum foil coil to be between 2.32 and 2.46 g / cm³; S4, during the annealing process, first heat from room temperature to 70-90°C, then keep warm for 12-24h; then heat to annealing temperature for annealing, and the heating rate should be controlled at 3-15°C / h; The flatness setting of the intermediate rolling pass is: the flatness of the plate shape 1 is -12I to -2I, the plate shape 2 is 0I, the plate shape 3 is -4I to -1I, and the plate shape 4 is 0I; the flatness setting of the finished rolling pass is: the plate shape 1 is -28I to -12I, the plate shape 2 is 0I, the plate shape 3 is -6I to -2I, and the plate shape 4 is 0I; the plate shape of the finished aluminum foil is measured on an offline plate shape meter, and the control range of the sag of the two sides is -8 to -2mm; The plate shape one refers to the plate shape value of the middle position in the width direction of the aluminum foil. A positive value indicates that the middle is loose, and a negative value indicates that the middle is tight; plate shape two refers to the plate shape inclination value of the two sides in the width direction of the aluminum foil. A positive value indicates that the operating side is tighter than the transmission side, and a negative value indicates that the operating side is looser than the transmission side; plate shape three refers to the plate shape index of the two sides of the aluminum foil along the width direction. A positive value indicates that the two sides are tight, and a negative value indicates that the two sides are loose; plate shape four refers to the plate shape value of the second rib position in the width direction of the aluminum foil. A positive value indicates that the two ribs are loose, and a negative value indicates that the two ribs are tight.

2. The production method for solving the blistering of double zero aluminum foil annealing according to claim 1 is characterized in that: In step S2, the surface purge pressure of the outlet aluminum foil of the finished rolling pass is 0.2-0.5 MPa.

3. The production method for solving the blistering of double zero aluminum foil annealing according to claim 1 is characterized in that: In step S3, the winding tension of the slit aluminum foil roll is 22-40 MPa, the support roller pressure is 2.0-3.0 N / mm, the flattening roller pressure is 1.0-2.0 N / mm, and the surface tension is 1-10 MPa.

4. The production method for solving the blistering of double zero aluminum foil annealing according to claim 1 is characterized in that: During the annealing process, the heating rate of each heating stage should be controlled: the heating rate of 0.007-0.009 mm aluminum foil is 10-15°C / h; the heating rate of 0.0058-0.007 mm aluminum foil is 6-10°C / h; the heating rate of 0.0045-0.0058 mm aluminum foil is 3-6°C / h.

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