Production method for improving white points on surface of brass strip for LED

Abstract

The invention discloses a production method for improving white spots on the surface of a brass strip for an LED. The production method comprises the following steps of hot rolling, double-sided milling, rough rolling, thick edge shearing, bell-type furnace annealing, degreasing and cleaning, intermediate rolling, primary annealing in an air cushion furnace, pre-finish rolling, secondary annealing in the air cushion furnace, degreasing and grinding, finish rolling, degreasing and cleaning, stretch bending and straightening, and splitting of a finished product. The reduction rate of finish rolling is 20-25%; the temperature of the secondary annealing of the air cushion furnace is 450-500 DEG C; the brass strip produced by the method is uniform in surface lines, does not have white points, can meet the coating requirement of a thin plating layer, and achieves the purposes of cost control and cost reduction.

Description

Technical Field

[0001] The invention belongs to the technical field of brass strip production, and in particular relates to a production method for improving white spots on the surface of a brass strip for LEDs. Background Art

[0002] Brass strips contain a high proportion of copper elements, so they have excellent electrical conductivity and are widely used in the LED field. For example, brass strips can be used to connect LED components, using their good electrical conductivity to ensure stable current transmission. LEDs generate heat during operation, and brass strips can be used to make heat sinks due to their good thermal conductivity, helping LEDs to quickly dissipate heat and extend their service life.

[0003] In order to improve the anti-oxidation, corrosion resistance, and electrical conductivity of brass strips, it is generally necessary to apply metal plating on the surface of the brass strips when using them. In order to reduce costs, customers are increasingly demanding thinner thicknesses, such as reducing the thickness of the brass strip surface from 2um to 0.5μm. The thinner coating thickness places higher demands on the surface quality of the brass strips, such as not allowing white spots on the surface texture of the brass strips. If there are white spots on the surface texture of the brass strips, the surface will become numb after electroplating and cannot meet product requirements.

[0004] Chinese patent CN115805436A discloses a method for producing a brass strip for LED with uniform surface texture, the production method comprising the following steps: melting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell furnace annealing → thick strip cleaning → first pre-finishing rolling → bell furnace annealing → in-process cleaning → second pre-finishing rolling → air cushion furnace annealing → finishing rolling → finished product cleaning → stretch bending and straightening → finished product stripping; in the air cushion furnace annealing step, the annealing temperature is 630-670°C, the annealing atmosphere is air, and the annealing speed is 80-100m / min; in the finishing rolling step, the roller roughness is controlled at 0.06-0.08um; the surface texture of the brass strip produced by the method of the present invention is fine and uniform, meeting the requirements for the use of LED products after tinning. Although this method can produce a brass strip with fine and uniform surface texture, it can be seen from the drawings disclosed in this patent that there are many white spots on the surface texture of the brass strip, and such a brass strip cannot meet the coating requirements of a coating thickness of less than 0.5 μm. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a production method for improving the white spots on the surface of a brass strip for LEDs. The brass strip produced by the method has uniform surface texture and no white spots.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A production method for improving white spots on the surface of a brass strip for LED, the production method comprising the following steps: hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping;

[0008] The temperature of the secondary annealing in the air cushion furnace is 450-500°C

[0009] The reduction ratio of the finish rolling is 20 to 25%.

[0010] In the hot rolling step, the heating temperature is controlled at 835-875° C., the stepping cycle is controlled at 540-720 s, the rolling force is controlled at 600-1000 KN, and the rolling speed is controlled at 90-130 m / min.

[0011] In the rough rolling step, the first rolling speed of the cogging is lower than 60 m / min, and the non-first rolling speed of the cogging is lower than 180 m / min.

[0012] In the bell-type furnace annealing step, the annealing temperature is 450-550° C., the annealing time is 5.0-8.0 hours, and the annealing atmosphere is a mixture of H2 and N2, wherein the volume percentage of N2 is 25-35%.

[0013] In the intermediate rolling step, the rolling rate is 150-180 m / min, the roughness of the rolling roller is 0.28-0.3 um, and the reduction rate of the intermediate rolling is 55-90%.

[0014] In the primary annealing step of the air cushion furnace, the annealing temperature is 600-700° C., the annealing speed is 40-55 m / min, and the annealing atmosphere is air.

[0015] In the pre-finishing rolling step, the rolling rate is 150-180 m / min, the roughness of the rolling roller is 0.15-0.18 um, and the reduction rate of the intermediate rolling is 20-40%.

[0016] In the secondary annealing step of the air cushion furnace, the annealing speed is 50-75 m / min, and the annealing atmosphere is air.

[0017] In the degreasing, cleaning and grinding step, the grinding brush used is 1000#-3000#, and the pressing current is 2.0~4.0A.

[0018] In the finishing rolling step, the rolling rate of the finishing rolling is 55-65 m / min, and the roughness of the rolling roll is 0.05-0.09 μm.

[0019] In the stretching and straightening step, the elongation is controlled at 1% to 4%.

[0020] In the production method for improving the white spots on the surface of the brass strip for LED provided by the present invention, during the secondary annealing in the air cushion furnace, the annealing temperature is controlled to be 450-500°C, so that the white spots caused by the dezincification phenomenon can be reduced, and a grinding process is added after the secondary annealing and cleaning in the air cushion furnace to eliminate the white spots caused by the dezincification phenomenon; the reduction rate of the finish rolling is controlled to be 20-25% to ensure that the texture on the surface of the brass strip is uniform.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The brass strip for LED produced by the production method provided by the present invention has uniform surface texture and no white spots, and can meet the coating requirements of a thinner coating, thereby achieving the purpose of controlling costs and reducing expenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a surface texture image of the brass strip in Example 1 observed under a 200x microscope;

[0024] Figure 2 This is a surface texture image of the brass strip in Example 2 observed under a 200x microscope;

[0025] Figure 3 This is a surface texture image of the brass strip in Example 3 observed under a 200x microscope;

[0026] Figure 4 This is a surface texture image of the brass strip in Example 4 observed under a 200x microscope;

[0027] Figure 5 This is a surface texture image of the brass strip in Example 5 observed under a 200x microscope;

[0028] Figure 6 This is a surface texture image of the brass strip in Comparative Example 1 observed under a 200x microscope;

[0029] Figure 7 This is a surface texture image of the brass strip in Comparative Example 2 observed under a 200x microscope.

[0030] Figure 8 This is a surface texture image of the brass strip in Comparative Example 3 observed under a 200x microscope. DETAILED DESCRIPTION

[0031] The present invention is described in detail below with reference to the embodiments.

[0032] The brass strips produced in the embodiments and comparative examples are all of grade C2680.

[0033] Example 1

[0034] A production method for improving white spots on the surface of a brass strip for LED, the production method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0035] Stepping furnace heating: heating temperature is controlled at 855℃, and stepping cycle is controlled at 600s;

[0036] Hot rolling: rolling force is controlled at 1000KN, and rolling speed is controlled at 130m / min;

[0037] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0038] Rough rolling: The first pass rolling speed is 50m / min, and the non-first pass rolling speed is 150m / min;

[0039] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0040] Bell-type furnace annealing: annealing temperature is 460°C, annealing time is 6.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 30%;

[0041] Medium rolling: rolling rate is 150m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.19mm;

[0042] Air cushion furnace primary annealing: annealing temperature is 650℃, annealing speed is 50m / min, annealing atmosphere is air;

[0043] Pre-finishing rolling: rolling rate is 180m / min, the roughness of the roller is 0.15um, and it is rolled from 0.19mm to 0.152mm;

[0044] Secondary annealing in air cushion furnace: annealing at 480°C at an annealing speed of 60m / min;

[0045] Grinding: 3000# polishing current 2.0A;

[0046] Finish rolling: rolling rate is 55m / min, roller roughness is 0.05μm, rolling from 0.152mm to 0.12mm;

[0047] Tension bending straightening: elongation 1%.

[0048] The hardness of the brass strip for LED produced in this embodiment is 150 HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 1 As shown in the figure, it can be seen that the surface texture of the copper strip is fine and uniform, and there are no white spots on the surface.

[0049] Example 2

[0050] A production method for improving white spots on the surface of a brass strip for LED, the production method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0051] Stepping furnace heating: heating temperature is controlled at 835℃, and stepping cycle is controlled at 540s;

[0052] Hot rolling: rolling force is controlled at 800KN, and rolling speed is controlled at 120m / min;

[0053] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0054] Rough rolling: The first pass rolling speed of billet opening is 55m / min, and the non-first pass rolling speed of billet opening is 170m / min;

[0055] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0056] Bell-type furnace annealing: annealing temperature is 470°C, annealing time is 5.5h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 25%;

[0057] Medium rolling: rolling rate is 160m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0058] Air cushion furnace primary annealing: annealing temperature is 660℃, annealing speed is 48m / min, annealing atmosphere is air;

[0059] Pre-finishing rolling: rolling rate is 150m / min, the roughness of the roller is 0.15um, and it is rolled from 0.20mm to 0.13mm;

[0060] Secondary annealing in air cushion furnace: annealing at 500°C at an annealing speed of 65m / min;

[0061] Grinding: 3000# polishing current 2.0A;

[0062] Finish rolling: rolling rate is 60m / min, roller roughness is 0.05μm, rolling from 0.13mm to 0.10mm;

[0063] Tension bending straightening: elongation 1%.

[0064] The hardness of the brass strip for LED produced in this embodiment is 149 HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 2 As shown in the figure, it can be seen that the surface texture of the copper strip is fine and uniform, and there are no white spots on the surface.

[0065] Example 3

[0066] A production method for improving white spots on the surface of a brass strip for LED, the production method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0067] Stepping furnace heating: heating temperature is controlled at 875℃, and stepping cycle is controlled at 540s;

[0068] Hot rolling: rolling force is controlled at 600KN, and rolling speed is controlled at 90m / min;

[0069] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0070] Rough rolling: The first pass rolling speed of billet opening is 55m / min, and the non-first pass rolling speed of billet opening is 175m / min;

[0071] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0072] Bell-type furnace annealing: annealing temperature is 550°C, annealing time is 5.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 28%;

[0073] Medium rolling: rolling rate is 165m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0074] Air cushion furnace primary annealing: annealing temperature is 700℃, annealing speed is 55m / min, annealing atmosphere is air;

[0075] Pre-finishing rolling: rolling rate is 160m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.155mm;

[0076] Secondary annealing in air cushion furnace: annealing at 490°C at an annealing speed of 55m / min;

[0077] Grinding: 2000# polishing current 2.0A;

[0078] Finish rolling: rolling rate is 65m / min, roller roughness is 0.05μm, rolling from 0.155mm to 0.12mm;

[0079] Tension bending straightening: elongation 1.5%.

[0080] The hardness of the brass strip for LED produced in this embodiment is 151 HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 3 As shown in the figure, it can be seen that the surface texture of the copper strip is fine and uniform, and there are no white spots on the surface.

[0081] Example 4

[0082] A production method for improving white spots on the surface of a brass strip for LED, the production method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0083] Stepping furnace heating: heating temperature is controlled at 865℃, and stepping cycle is controlled at 650s;

[0084] Hot rolling: rolling force is controlled at 750KN, and rolling speed is controlled at 100m / min;

[0085] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0086] Rough rolling: The first pass rolling speed of billet opening is 55m / min, and the non-first pass rolling speed of billet opening is 150m / min;

[0087] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0088] Bell-type furnace annealing: annealing temperature is 520°C, annealing time is 7.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 35%;

[0089] Medium rolling: rolling rate is 180m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0090] Air cushion furnace primary annealing: annealing temperature is 690℃, annealing speed is 43m / min, annealing atmosphere is air;

[0091] Pre-finishing rolling: rolling rate is 170m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.14mm;

[0092] Secondary annealing in air cushion furnace: annealing at 470°C at an annealing speed of 55m / min;

[0093] Grinding: 1000# polishing current 2.0A;

[0094] Finish rolling: rolling rate is 58m / min, roller roughness is 0.05μm, rolling from 0.14mm to 0.105mm;

[0095] Tension bending straightening: elongation 1.5%.

[0096] The hardness of the brass strip for LED produced in this embodiment is 153 HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 4 As shown in the figure, it can be seen that the surface texture of the copper strip is fine and uniform, and there are no white spots on the surface.

[0097] Example 5

[0098] A production method for improving white spots on the surface of a brass strip for LED, the production method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and cleaning → grinding → finishing rolling → degreasing and cleaning → bending and straightening → finished product stripping; specifically:

[0099] Stepping furnace heating: heating temperature is controlled at 840℃, and stepping cycle is controlled at 715s;

[0100] Hot rolling: rolling force is controlled at 750KN, and rolling speed is controlled at 110m / min;

[0101] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0102] Rough rolling: The first rolling speed of billet opening is 58m / min, and the rolling speed of non-first rolling speed of billet opening is less than 175m / min;

[0103] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0104] Bell-type furnace annealing: annealing temperature is 505°C, annealing time is 7.5h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 28%;

[0105] Medium rolling: rolling rate is 170m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0106] Air cushion furnace primary annealing: annealing temperature is 660℃, annealing speed is 45m / min, annealing atmosphere is air;

[0107] Pre-finishing rolling: rolling rate is 180m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.14mm;

[0108] Secondary annealing in air cushion furnace: annealing at 460°C at an annealing speed of 70m / min;

[0109] Grinding: 2000# polishing current 2.0A;

[0110] Finish rolling: rolling rate is 64m / min, roller roughness is 0.05μm, rolling from 0.14mm to 0.11mm;

[0111] Tension bending straightening: elongation 4.0%.

[0112] The hardness of the brass strip for LED produced in this embodiment is 155 HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 5 As shown in the figure, it can be seen that the surface texture of the copper strip is fine and uniform, and there are no white spots on the surface.

[0113] Comparative Example 1

[0114] A method for producing a brass strip for LED, the method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0115] Stepping furnace heating: heating temperature is controlled at 855℃, and stepping cycle is controlled at 600s;

[0116] Hot rolling: rolling force is controlled at 1000KN, and rolling speed is controlled at 130m / min;

[0117] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0118] Rough rolling: The first rolling speed of the billet is 50m / min, and the non-first rolling speed of the billet is 170m / min;

[0119] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0120] Bell-type furnace annealing: annealing temperature is 460°C, annealing time is 6.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 25%;

[0121] Medium rolling: rolling rate is 150m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0122] Air cushion furnace primary annealing: annealing temperature is 650℃, annealing speed is 50m / min, annealing atmosphere is air;

[0123] Pre-finishing rolling: rolling rate is 150m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.12mm;

[0124] Secondary annealing in air cushion furnace: annealing at 490°C at an annealing speed of 60m / min;

[0125] Grinding: 3000# polishing current 2.0A;

[0126] Finish rolling: The rolling rate of the finish rolling is 60m / min, the roll roughness is 0.05μm, and the rolling is from 0.12mm to 0.11mm;

[0127] Tension bending straightening: elongation 1.5%.

[0128] The hardness of the brass strip for LED produced in this comparative example is 150HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 6 As shown in the figure, it can be seen that there are many white spots on the surface of the copper strip.

[0129] Comparative Example 2

[0130] A method for producing a brass strip for LED, the method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0131] Stepping furnace heating: heating temperature is controlled at 855℃, and stepping cycle is controlled at 600s;

[0132] Hot rolling: rolling force is controlled at 1000KN, and rolling speed is controlled at 130m / min;

[0133] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0134] Rough rolling: The first rolling speed of the billet is 50m / min, and the non-first rolling speed of the billet is 170m / min;

[0135] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0136] Bell-type furnace annealing: annealing temperature is 460°C, annealing time is 6.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 25%;

[0137] Medium rolling: rolling rate is 150m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0138] Air cushion furnace primary annealing: annealing temperature is 650℃, annealing speed is 50m / min, annealing atmosphere is air;

[0139] Pre-finishing rolling: rolling rate is 160m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.12mm;

[0140] Secondary annealing in air cushion furnace: annealing at 490°C at an annealing speed of 60m / min;

[0141] Finish rolling: rolling rate is 60m / min, the roughness of the roller is 0.05um, and it is rolled from 0.12mm to 0.11mm;

[0142] Tension bending straightening: elongation 1.5%.

[0143] The hardness of the brass strip for LED produced in this comparative example is 150HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 7 As shown in the figure, it can be seen that there are many white spots on the surface of the copper strip.

[0144] Comparative Example 3

[0145] A method for producing a brass strip for LED, the method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0146] Stepping furnace heating: heating temperature is controlled at 855℃, and stepping cycle is controlled at 600s;

[0147] Hot rolling: rolling force is controlled at 1000KN, and rolling speed is controlled at 130m / min;

[0148] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0149] Rough rolling: The first pass rolling speed of billet opening is 50m / min, and the non-first pass rolling speed of billet opening is 160m / min;

[0150] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0151] Bell-type furnace annealing: annealing temperature is 460°C, annealing time is 6.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 28%;

[0152] Medium rolling: rolling rate is 170m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0153] Air cushion furnace primary annealing: annealing temperature is 650℃, annealing speed is 50m / min, annealing atmosphere is air;

[0154] Pre-finishing rolling: rolling rate is 150m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.14mm;

[0155] Secondary annealing in air cushion furnace: annealing at 650℃ with an annealing speed of 100m / min;

[0156] Grinding: 3000# polishing current 2.0A;

[0157] Finish rolling: The rolling rate of the finish rolling is 60m / min, the roll roughness is 0.05μm, and the rolling is from 0.14mm to 0.11mm;

[0158] Tension bending straightening: elongation 1.5%.

[0159] The hardness of the brass strip for LED produced in this comparative example is 130HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 8 As shown in the figure, it can be seen that there are many white spots on the surface of the copper strip and the mechanical properties are unqualified.

[0160] Comparative Example 4

[0161] A method for producing a brass strip for LED, the method comprising the following steps: smelting → casting → sawing → heating in a walking furnace → hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → finishing rolling → degreasing and cleaning → stretching and straightening → finished product stripping; specifically:

[0162] Stepping furnace heating: heating temperature is controlled at 855℃, and stepping cycle is controlled at 600s;

[0163] Hot rolling: rolling force is controlled at 1000KN, and rolling speed is controlled at 130m / min;

[0164] Double-sided milling: The single-sided milling amount is 0.8mm, the single-sided milling amount is 3mm, and the equipment running speed is controlled at 6m / s;

[0165] Rough rolling: The rolling speed of the first pass of billet opening is less than 60m / min, and the rolling speed of non-first pass of billet opening is less than 180m / min;

[0166] Thick shear edge: Thick longitudinal shear width 35mm, shear speed controlled at 100m / min;

[0167] Bell-type furnace annealing: annealing temperature is 460°C, annealing time is 6.0h, annealing atmosphere is a mixture of H2 and N2, in which the volume percentage of N2 is 25%;

[0168] Medium rolling: rolling rate is 150m / min, the roughness of the roller is 0.3um, and it is rolled from 0.8mm to 0.197mm;

[0169] Air cushion furnace primary annealing: annealing temperature is 650℃, annealing speed is 50m / min, annealing atmosphere is air;

[0170] Pre-finishing rolling: rolling rate is 150m / min, the roughness of the roller is 0.15um, and it is rolled from 0.197mm to 0.14mm;

[0171] Secondary annealing in air cushion furnace: annealing at 650℃ with an annealing speed of 100m / min;

[0172] Grinding: No grinding;

[0173] Finish rolling: rolling from 0.14mm to 0.11mm;

[0174] Tension bending straightening: elongation 1.5%.

[0175] The hardness of the brass strip for LED produced in this comparative example is 130HV. The surface texture thereof observed under a 200x microscope is as follows: Figure 8 As shown in the figure, it can be seen that there are many white spots on the surface of the copper strip and the mechanical properties are unqualified.

[0176] From the above comparison, it can be seen that the brass strips for LED produced in each embodiment have no white spots on the surface, and the hardness of the brass strips reaches 140HV or more. In Comparative Example 1, due to the low reduction rate of fine rolling, there are more white spots on the surface of the copper strip; in Comparative Example 2, due to the lack of grinding after the secondary annealing in the air cushion furnace and the low reduction rate of fine rolling, there are more white spots on the surface of the copper strip; in Comparative Example 3, due to the high temperature of the secondary annealing in the air cushion furnace, there are more white spots on the surface of the copper strip, and the hardness is low; in Comparative Example 4, due to the high temperature of the secondary annealing in the air cushion furnace and the lack of grinding after the secondary annealing in the air cushion furnace, there are more white spots on the surface of the copper strip, and the hardness is low.

[0177] The above-mentioned detailed description of a production method for improving white spots on the surface of brass strips for LEDs with reference to the embodiments is illustrative rather than restrictive, and several embodiments can be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A production method for improving white spots on the surface of brass strips for LEDs, characterized in that: The production method comprises the following steps: hot rolling → double-sided milling → rough rolling → thick shearing edge → bell-type furnace annealing → degreasing and cleaning → intermediate rolling → primary annealing in an air cushion furnace → pre-finishing rolling → secondary annealing in an air cushion furnace → degreasing and grinding → finishing rolling → degreasing and cleaning → stretching, bending and straightening → finished product stripping; The temperature of the secondary annealing in the air cushion furnace is 450-500°C; The reduction ratio of the finish rolling is 20 to 25%.

2. The production method according to claim 1, characterized in that In the hot rolling step, the heating temperature is controlled at 835-875° C., the stepping cycle is controlled at 540-720 s, the rolling force is controlled at 600-1000 KN, and the rolling speed is controlled at 90-130 m / min.

3. The production method according to claim 1, characterized in that In the rough rolling step, the rolling speed of the first pass of the cogging is lower than 60 m / min, and the rolling speed of the non-first pass of the cogging is lower than 180 m / min.

4. The production method according to claim 1, characterized in that In the bell-type furnace annealing step, the annealing temperature is 450-550° C., the annealing time is 5.0-8.0 hours, and the annealing atmosphere is a mixture of H2 and N2, wherein the volume percentage of N2 is 25-35%.

5. The production method according to claim 1, characterized in that: In the intermediate rolling step, the rolling rate is 150-180 m / min, the roughness of the rolling roller is 0.28-0.3 um, and the reduction rate of the intermediate rolling is 55-90%.

6. The production method according to claim 1, characterized in that: In the primary annealing step of the air cushion furnace, the annealing temperature is 600-700° C., the annealing speed is 40-55 m / min, and the annealing atmosphere is air.

7. The production method according to claim 1, characterized in that: In the pre-finishing rolling step, the rolling rate is 150-180 m / min, the roughness of the rolling roller is 0.15-0.18 um, and the reduction rate of the intermediate rolling is 20-40%.

8. The production method according to claim 1, characterized in that: In the secondary annealing step of the air cushion furnace, the annealing speed is 50-75 m / min, and the annealing atmosphere is air.

9. The production method according to claim 1, characterized in that: In the degreasing and grinding step, the grinding brush used is 1000#-3000#, and the pressing current is 2.0-4.0A.

10. The production method according to claim 1, characterized in that: In the finishing rolling step, the finishing rolling rate is 55-65 m / min, and the roller roughness is 0.05-0.09 μm.

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