Method for reducing warping occurrence rate of tin-plated plate

Abstract

The invention relates to a method for reducing the incidence rate of warping of a tin plate, which comprises the following steps of: S1, limiting the setting range of the elongation of a withdrawal and straightening machine; s2, the adjustment range of the insertion amount of the withdrawal and straightening machine is limited; s3, the layout of the straightening unit rollers is modified; s4, redesigning the shaft head structure of the straightening roller; through the steps, the warping occurrence rate of the tin-plated plate can be reduced, the failure rate of a straightening machine is reduced, and production is stable.

Description

Technical Field

[0001] The invention belongs to the technical field of strip steel straightening, and specifically is a method for reducing the occurrence rate of warping of tinplate. Background Art

[0002] Tinplate is an extremely thin layer of tin electroplated on a substrate. It is widely used in food packaging materials, such as common can materials. Tinplate is generally very thin, with a thickness between 0.15-0.25mm. The flatness and stability of the plate shape are of great significance for subsequent printing, cutting, and round welding.

[0003] At present, our company's tinning unit has the following problems: the warping problem of thin-gauge DR materials (Magang) is quite serious. During production and customer use, it was found that some DR materials have obvious upward warping, which has an adverse effect on customer printing;

[0004] In order to improve the warping, the straightening machine had to adopt a straightening unit with a large amount of insertion. As the inlet load of the straightening unit continued to increase, the shaft head of the straightening roller of the straightening machine was frequently burned, with an average of 8 shaft heads burned per month, resulting in 12 tons of waste, which seriously affected the stable operation of the tinning unit.

[0005] According to statistics of the production in the past year, the products with unqualified warping are mainly plates with a thickness of 0.15-0.18mm; the warping rate is 0.16%;

[0006] After consulting the data, the warping rate of foreign thin-gauge DR sheets is only 0.05%; therefore, it is necessary to find a way to reduce the warping rate of tinplate.

[0007] In the existing patent, the application number is CN201710600541.1, and the name is a method for producing tin-plated sheets and tin-plated substrates. It discloses a generation method including: using a double-frame flattening machine to produce tin-plated substrates; in the generation process, the plate shape target curve of the tin-plated substrate adopts a micro-double-sided wave mode: a tin-plated straightening machine is used to control the warping height of the tin-plated substrate, and the tin-plated straightening machine includes: a first bending roller, a second bending roller and a straightening roller; in the process of warping quality control, the insertion amount A of the first bending roller, the insertion amount B of the second bending roller, the insertion amount C of the straightening roller inlet and the insertion amount D of the straightening roller outlet are controlled to [0.6mm]; the elongation E3 of the straightening machine is controlled to 0.0.5%; the method adjusts the insertion amount of the bending roller, which is easy to cause damage to the shaft head, which needs to be solved;

[0008] There is also an application number CN201810715405.1, entitled A method for producing tinplate substrates based on a hood annealing process, which discloses the following steps: degreasing and cleaning a cold-rolled plate having a thickness of 0.414 to 0.356 mm and a width of 800 to 900 mm, hood annealing, and secondary flattening and pressing to prepare a secondary cold-rolled tinplate substrate; wherein the hot spot of the hood annealing is controlled to 600°C and the cold spot is controlled to 570°C; the secondary flattening is performed by a flattening unit, and the secondary flattening reduction rate is controlled to 10% to 23%. The first frame of the flattening unit adopts a continuously variable convex roller shape with a roller surface roughness of 0.4μm, and the second frame of the flattening unit adopts a double-sided chamfered flat roller shape with a roller surface roughness of 2.0μm. Secondary cold rolling is required, and the process is complicated. Summary of the invention

[0009] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is: how to provide a method to reduce the incidence of warping of tinplate, which can reduce the incidence of warping of tinplate, improve the product qualification rate and reduce enterprise losses.

[0010] The technical solution of the present invention is:

[0011] A method for reducing the incidence of warping of tinplate comprises the following steps:

[0012] S1, limits the setting range of the elongation of the tension leveler;

[0013] S2, limits the adjustment range of the insertion amount of the tension leveler;

[0014] S3, modify the straightening unit roller layout;

[0015] S4, redesign the straightening roller head structure.

[0016] Furthermore, in step S1, the upper limit of the adjustable range of the elongation of the tension leveler is adjusted from 0.5% to 0.25% to avoid uneven plastic deformation of the upper and lower surfaces of the strip when the strip passes through the bending rolls with a large elongation.

[0017] Furthermore, in step S2, for DR material strip with a thickness not exceeding 0.18 mm, the upper limit of the bending roller insertion amount is adjusted from 8 mm to 6 mm; the bending roller insertion amount at the straightening entrance is 2-4 mm, and the bending roller insertion amount at the straightening exit is 0.5-1.5 mm.

[0018] In the step S3, the straightening roller group unit is changed from the original upper four and lower five structure to an upper four and lower four structure.

[0019] Furthermore, the straightening roller shaft head structure includes a thickened straightening roller shaft head, an angular contact bearing and a disc spring;

[0020] The diameter of the straightening roller shaft head at both ends of the straightening roller is increased by 10 mm; two angular contact bearings are arranged on the straightening roller shaft head at each end, a disc spring is arranged between the two angular contact bearings, and the two angular contact bearings are arranged back to back.

[0021] Furthermore, the four-upper-four-lower structure has four straightening rollers on the upper side of the steel strip and four straightening rollers on the lower side of the steel strip.

[0022] The beneficial effects of the present invention are:

[0023] By setting the upper limit of the elongation of the tension leveler, warping caused by excessive stretching can be avoided;

[0024] By setting the adjustment range of the insertion amount; the upper limit of the bending roller insertion amount is changed from the original 8mm to 6mm, the straightening entrance insertion amount is 2-4mm, and the straightening exit insertion amount is 0.5-1.5mm; it can effectively avoid over-tensioning and reduce warping caused by plastic deformation;

[0025] By modifying the layout of the straightening unit rollers, the straightening roller group unit was changed from the original upper four and lower five structure to the upper four and lower four structure. The plate warping control ability was greatly improved, the plate warping was avoided, and the number of shaft head burnouts was significantly reduced.

[0026] The straightening roller shaft head structure provided includes a thickened straightening roller shaft head, an angular contact bearing and a disc spring; the diameter of the straightening roller shaft heads at both ends of the straightening roller is increased by 10 mm; two angular contact bearings are provided on the straightening roller shaft head at each end, a disc spring is provided between the two angular contact bearings, and the two angular contact bearings are arranged back to back; due to the increase in the diameter of the shaft head, the bearing capacity of the shaft head is greatly improved, and the shaft head is not easy to burn out; one angular contact bearing is added, and a disc spring is added between the bearings, which can absorb the axial force of the straightening roller and avoid bearing damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a principle block diagram of the present invention;

[0028] Figure 2 This is a schematic front view of the improved structure of the straightening roller shaft head of the present invention.

[0029] In the accompanying drawings,

[0030] 1-straightening roller shaft head, 2-first angular contact bearing, 3-first disc spring, 4-second disc spring, 5-second angular contact bearing, 6-first locking nut, 7-second locking nut. DETAILED DESCRIPTION

[0031] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0032] Example 1

[0033] A method for reducing the incidence of warping of tinplate comprises the following steps:

[0034] S1, limit the setting range of the elongation of the straightening machine; in the step S1, the upper limit of the adjustable range of the elongation of the straightening machine is adjusted from 0.5% to 0.25% to avoid uneven plastic deformation of the upper and lower surfaces of the strip when the strip has a large elongation passing through the bending roll.

[0035] Orthogonal test was conducted on the elongation of the tension straightening machine, as shown in the following table

[0036]

[0037] From the table above, we can see that the significance of the influence on the elongation of the upper and lower surfaces of the strip is from high to low: straightening roller entrance insertion depth (mm) > tension straightening machine elongation (%) > straightening roller outlet insertion depth (mm) > No. 2 bending roller insertion depth (mm) > No. 1 bending roller insertion depth (mm)

[0038] When the elongation of the straightening machine is greater than 0.25, the warping ratio of the DR material strip increases significantly; the range of the elongation value of the straightening machine is adjusted from the original 0.6% to less than or equal to 0.25%.

[0039] According to the upper limit of elongation of 0.18%-0.25%, 2,500 tons of 0.18mm DR material were produced; and warpage detection was carried out on each roll. The warpage exceeding the standard rate was 0.12%, which was 0.04% lower than before the improvement; the effect was obvious.

[0040] S2, limits the adjustment range of the insertion amount of the tension leveler;

[0041] In the step S2, for DR material strip steel with a thickness not greater than 0.18 mm, the upper limit of the bending roller insertion amount is adjusted from 8 mm to 6 mm; the bending roller insertion amount at the straightening entrance is 2-4 mm, and the bending roller insertion amount at the straightening exit is 0.5-1.5 mm.

[0042] By measuring the warpage height of tinplate and analyzing the influence of single factor parameters, it is found that when the insertion amount of the bending roller is greater than 6mm, the warpage ratio increases significantly.

[0043] According to this procedure, 1,500 tons of DR plates with a thickness below 0.18 mm were produced, and warpage detection was performed on each roll. The warpage exceeding the standard rate was 0.09%, which was 0.07% lower than before the improvement. The effect was obvious.

[0044] S3, modify the straightening unit roller layout;

[0045] In the step S3, the straightening roller group unit is changed from the original upper four and lower five structure to an upper four and lower four structure.

[0046] The four-upper-four-lower structure has four straightening rollers on the upper side of the steel strip and four straightening rollers on the lower side of the steel strip.

[0047] The structure of the straightening unit of the tinning unit was originally four rollers on the top and five rollers on the bottom. It was changed to a structure of four rollers on the top and four rollers on the bottom. The last lower roller at the bottom was removed, and the insertion amount of the straightening outlet was adjusted. The ability to control plate warping was greatly improved, and the number of shaft head burns was reduced. This shows that reducing one lower roller has an impact on controlling the plate shape. This structure can effectively reduce the load in the entrance area and stabilize the deformation of the plate, and has a significant effect on reducing shaft head burns and plate deformation.

[0048] After the improvement according to this step, 2,500 tons of DR plates with a thickness below 0.18 mm were produced, and warpage detection was carried out roll by roll. The warpage exceeding standard rate was 0.05%, which was 0.11% lower than before the improvement. The effect was very obvious.

[0049] Example 2

[0050] It was found during use that even after the above-mentioned improvements, the straightening roller shaft head still burned out, and it was necessary to redesign the straightening roller shaft head structure.

[0051] The improved structure of the straightening roller shaft head comprises a straightening roller shaft head 1, a first angular contact bearing 2, a first disc spring 3 and a second disc spring 4, a second angular contact bearing 5, a first locking nut 6 and a second locking nut 7, which are sequentially installed on the shaft head 1 from the inside to the outside;

[0052] Two angular contact bearings are arranged on the straightening roller shaft head at each end, and a disc spring is arranged between the two angular contact bearings, and the two angular contact bearings are arranged opposite to each other. The disc spring can absorb the axial force borne by the straightening angular contact bearing during straightening, thereby extending the service life of the bearing.

[0053] The shaft heads with new structure were put into mass production and there was no damage to the shaft heads.

[0054] According to this procedure, 2,500 tons of DR plates with a thickness below 0.18 mm were produced, and warpage detection was performed on each roll. The warpage exceeding the standard rate was 0, which was 0.16% lower than before the improvement. The measures have achieved remarkable results.

[0055] Through the improvement of the above four steps, the occurrence rate of DR plate warping is reduced, and the stable production of the tin-plating unit is actively promoted. The number of stops for shaft change is reduced by 8 times per month, which has a significant effect on the overall process and quality stability of the unit. It is of positive significance to enhance the market image of tin-plated plate products and increase market share.

[0056] Example 3

[0057] This embodiment improves the shaft head 1 on the basis of Embodiment 2, and the diameter of the shaft heads of the straightening rollers at both ends of the straightening rollers is increased by 10 mm; by increasing the diameter, the life of the shaft head 1 can be extended.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for reducing the incidence of warping of tinplate, characterized in that: The method comprises the following steps: S1, limiting the setting range of the elongation of the tension leveler; S2, limits the adjustment range of the insertion amount of the tension and leveling machine; S3, modify the straightening unit roller layout.

2. A method for reducing the incidence of warping of tinplate according to claim 1, characterized in that: In the step S1, the upper limit of the adjustable range of the elongation of the tension leveler is adjusted from 0.5% to 0.25% to avoid uneven plastic deformation of the upper and lower surfaces of the strip when the strip passes through the bending rolls with a large elongation.

3. The method for reducing the incidence of warping of tinplate according to claim 1, characterized in that: In the step S2, for DR material strip steel with a thickness not greater than 0.18 mm, the upper limit of the bending roller insertion amount is adjusted from 8 mm to 6 mm; the bending roller insertion amount at the straightening entrance is 2-4 mm, and the bending roller insertion amount at the straightening exit is 0.5-1.5 mm.

4. The method for reducing the incidence of warping of tinplate according to claim 1, characterized in that: In the step S3, the straightening roller group unit is changed from the original upper four and lower five structure to an upper four and lower four structure.

5. The method for reducing the incidence of warping of tinplate according to claim 1, characterized in that: The four-upper-four-lower structure has four straightening rollers above the steel strip and four straightening rollers below the steel strip.

6. A method for reducing the incidence of warping of tinplate according to claim 4, characterized in that: It also includes S4, which improves the structure of the straightening roller head.

7. According to a method for reducing the incidence of warping of tinplate as described in claim 6, the improved structure of the straightening roller shaft head includes a thickened straightening roller shaft head, an angular contact bearing and a disc spring. The diameter of the straightening roller shaft head at both ends of the straightening roller is increased by 10 mm; two angular contact bearings are provided on the straightening roller shaft head at each end, a disc spring is provided between the two angular contact bearings, and the two angular contact bearings are arranged back to back.

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