Anti-adhesion treatment method suitable for bell-type annealing of copper alloy strips

Abstract

The present invention belongs to the technical field of continuous production of copper alloy strips, and relates to an anti-adhesion treatment method suitable for bell-type annealing of copper alloy strips, which is used for alleviating the edge adhesion phenomenon of copper alloy strips after bell-type annealing, reducing the problems of surface damage and deformation caused by edge adhesion, and reducing the rejection rate. In the present invention, by means of improving the sheet shape consistency of a material coil before annealing and using a low-viscosity oil film as an interlayer spacer of the material coil, it is ensured that material is uniformly stressed during a coiling process; then, the tension and self-weight differences of inner and outer rings of the coiled material are used during recoiling, and by means of using stepped coiling tension, optimizing the coiling manner, using a dedicated tower-shaped projecting-surface material disc in conjunction, with the position of a sleeve at the center of the material coil serving as a main bearing portion, and controlling the rate of a material temperature change stage in an annealing stage to reduce thermal stress, the stress concentration phenomenon at the edge of a strip coil can be effectively alleviated, thereby alleviating the problem of edge adhesion.

Description

Anti-adhesion treatment method suitable for hood annealing of copper alloy strip TECHNICAL FIELD

[0001] The present application belongs to the technical field of continuous production of copper alloy strip, and particularly relates to an anti-adhesion treatment method suitable for hood annealing of copper alloy strip. BACKGROUND

[0002] Affected by international and domestic demand, combined with the disorderly competition within the industry, the market pressure of copper alloy strip processing enterprises continues to increase, and it is urgent to improve quality and reduce cost for survival and development.

[0003] Hood annealing is an important heat treatment method adopted in the processing of copper alloy strip, which can significantly improve the electrical conductivity of the product, improve the work-hardened state and obtain the expected performance range. However, due to the use of coil heat treatment, the traditional hood annealing has the following problems: on the one hand, under high temperature conditions, the edge of the strip contacts the tray, which may cause local stress concentration, resulting in edge adhesion; on the other hand, repeated use of the tray in a high temperature environment may cause local deformation, which may further exacerbate the edge adhesion of the loaded strip. The adhesion of the copper alloy strip may cause significant surface damage and local physical property changes, resulting in a large amount of waste; in addition, tearing may occur when the strip is unfolded after annealing, which not only changes the shape of the edge position, but also changes the shape of the adjacent area, thereby affecting the use of the downstream customers in the punching and electroplating processes. SUMMARY

[0004] The present application aims to improve the edge adhesion phenomenon after hood annealing of copper alloy strip, reduce surface damage and deformation caused by edge adhesion, and reduce the waste rate. Therefore, an anti-adhesion treatment method suitable for hood annealing of copper alloy strip is provided.

[0005] The concept of the present application is as follows: first, by means of large processing rate deformation treatment, plastic deformation can be uniformly distributed in the material, which can effectively improve the consistency of the structure, but the use of excessive processing rate may cause sharp changes in the performance of the material in a high temperature environment, which may exacerbate the adhesion phenomenon; then, by means of multi-pass rolling and small processing rate rolling in the last pass, the sharp change in shape can be avoided; by using convex upper rollers and flat lower rollers, the shape of the plate can be controlled to be a middle wave, thereby reducing the risk of edge adhesion; the transverse difference and the two-edge difference of the rolled product are strictly controlled to ensure that the material is uniformly stressed during coiling; during re-coiling, by using the difference in tension and weight between the inner and outer circles of the coiled material, adopting stepwise coiling tension, optimizing the coiling method, and using a special tower-shaped convex tray, the sleeve position at the center of the material coil is used as the main bearing part, and a part of the displacement allowance due to collapse is reserved, which can effectively alleviate the stress concentration phenomenon at the edge of the coiled strip; finally, by controlling the rate of temperature change of the material, the thermal stress is reduced, thereby systematically improving the edge adhesion problem.

[0006] The technical scheme adopted by the present application is:

[0007] A method for preventing adhesion of copper alloy strip cover annealing, wherein a deformation processing rate of 50% to 70% is given in the rolling stage before annealing, then a gradually decreasing way is adopted to distribute the rolling process of not less than 4 passes, and the rolling processing rate of the last pass is controlled to be less than 12%; the upper work roll uses a roll type with a crown of 0.02mm to 0.05mm, the lower roll is a flat roll, and the plate shape control strategy is middle wave; the transverse difference of the product is controlled to be less than 1% of the thickness size, and the both-side difference is controlled to be less than 0.5% of the thickness size by controlling the bending roll force and adjusting the deviation.

[0008] Before copper alloy strip cover annealing, the strip is re-coiled, specifically as follows: a stepwise coiling tension is adopted in the re-coiling process, that is, the coiling tension is gradually increased by 1 to 3 N / mm2 at 3 to 4 equal parts of the coil; the coil is coiled on a steel sleeve; a spraying method is adopted to spray mineral oil with a viscosity of less than or equal to 10mm / s to the surface of the material during the re-coiling process. 2

[0009] During copper alloy strip cover annealing, the following methods are adopted: a tower-shaped cover annealing coil loading coil is used, the coil is placed below, and the tower surface contacts the coiled strip; a temperature rising rate of not more than 80℃ / h is given in the heating stage; a cooling rate of not more than 50℃ / h is given in the cooling stage above 200℃, and a cooling rate of not more than 30℃ / h is given in the cooling stage below 200℃.

[0010] Further, the sleeve width should be greater than or equal to the coil width + 15 to 30mm, and the coil edge is aligned with the sleeve edge by 3 to 10mm, that is, the strip is not coiled in the center of the sleeve during re-coiling, but is coiled eccentrically, and the coil edge is 3 to 10mm away from the sleeve edge after coiling, leaving a margin for displacement due to collapse, which can effectively alleviate the stress concentration phenomenon at the edge of the coiled strip.

[0011] Further, the tower-shaped core of the coil is raised, the tower shape is 2 to 5mm, the steel sleeve is supported on the tower-shaped coil during coil loading, the sleeve position serves as the main load-bearing part, the side of the sleeve on which the coil is coiled is vertically downward, and there is a gap between the tower surface of the coil and the coil after annealing.

[0012] Compared with the prior art, the present application has the following beneficial effects:

[0013] After the copper alloy strip is treated according to the above technical scheme, no obvious deformation area appears at the edge position of the coil after heat treatment at a temperature of 650℃ or above; and no edge adhesion phenomenon occurs during uncoiling of the coil on the cleaning line.​BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of the special tower-shaped cover annealing material disc structure used in the present application.

[0015] Figure 2 is a side view of Figure 1.

[0016] In the figure: 1 - core, 2 - tower-shaped surface. DETAILED DESCRIPTION

[0017] The present application will be further described in detail below in conjunction with the accompanying drawings and examples.

[0018] Example 1

[0019] In this example 1, the strip thickness is 1.5 mm and the width is 450 mm. A deformation processing rate of 62.5% is given in the rolling stage before annealing, and the rolling process is distributed in 4 passes with pass processing rates of 30%, 25%, 19% and 11.8% respectively. The work roll profile used in rolling is convex with a convexity of 0.03 mm, the lower roll is flat, and the plate shape control strategy is intermediate wave. Through control of bending force and deflection, the transverse difference of the product is controlled to be less than 0.015 mm, and the difference between the two sides is controlled to be less than 0.007 mm of the thickness size.

[0020] Before copper alloy strip cover annealing, the strip is re-coiled as follows: before copper alloy strip cover annealing, the strip is re-coiled with a coiling tension of 26 N / mm2, and the coiling tension is increased by 2 N / mm2 at 1 / 3 and 2 / 3 positions respectively, and the strip is coiled on a steel sleeve (the sleeve width is 480 mm, and the edge of the coil is aligned with the edge of the sleeve by 3 mm). In the re-coiling process, mineral oil with a viscosity of ≤10 mm / s is sprayed to the surface of the material in a spraying manner. Then the coil is placed horizontally on the special tower-shaped convex material disc by the material turning machine (the tower shape is 3 mm, the sleeve is supported on the material disc, the tower-shaped surface of the material disc is vertically upward, the side of the sleeve on which the coil is coiled is vertically downward, and there is a gap between the tower-shaped surface of the material disc and the coil). 2

[0021] During copper alloy strip cover annealing, the following methods are adopted: a special tower-shaped (core protrusion, tower shape 3 mm) cover annealing coil is used, which is made of 309S stainless steel as the base material, and the coil is loaded on the material disc placed below, and the tower-shaped surface contacts the coiled strip. It is hoisted to the furnace table area for heat treatment at a temperature of 550°C, and a heating rate of 50-80°C / h is given in the heating stage. In the cooling stage above 200°C, the inner shell is cooled by air, and the cooling rate is 40-45°C / h. In the cooling stage below 200°C, the inner shell is cooled by water, and a cooling rate of 20-30°C / h is given. After annealing, there is also a gap between the tower-shaped surface of the material disc and the coil.

[0022] The coiled strip of Example 1 was unwound and washed on a washing line without any obvious deformation at the edge of the coil, and no edge sticking occurred during unwinding.

[0023] Example 2

[0024] In this example 2, the strip thickness was 0.5 mm and the width was 430 mm. A deformation processing rate of 66.7% was given to the strip before annealing, and the rolling process was distributed in 5 passes with pass processing rates of 26.7%, 24.5%, 20.5%, 15.1%, and 10.7%, respectively. During rolling, a convexity of 0.015 mm was used for the upper work roll, the lower roll was flat, and the shape control strategy was middle wave. The transverse difference of the product was controlled to be less than 0.005 mm, and the two edge differences were controlled to be less than 0.002 mm of the thickness size by controlling the bending force and adjusting the offset.

[0025] Before the copper alloy strip was cover annealed, the strip was re-coiled as follows: before the copper alloy strip was cover annealed, the strip was re-coiled with a coiling tension of 18 N / mm2, and the coiling tension was increased by 2 N / mm2 at 1 / 4, 1 / 2, and 3 / 4 positions, respectively, and the strip was coiled on a steel sleeve (the sleeve width was 450 mm, and the coil edge was aligned with the sleeve edge by 3 mm). Then the coil was placed horizontally on a special tower-shaped convex coil tray by a coil turning machine (the tower shape was 2 mm, the coil edge was vertically downward on the side close to the sleeve, and the tray tower surface was vertically upward). During the re-coiling process, mineral oil with a viscosity of ≤10 mm / s was sprayed onto the surface of the material by spraying. Then the coil was placed horizontally on a special tower-shaped convex coil tray by a coil turning machine (the tower shape was 2 mm, the sleeve was supported on the tray, the tray tower surface was vertically upward, the side of the sleeve on which the coil was coiled was vertically downward, and there was a gap between the tray tower surface and the coil). 2 / s of mineral oil was sprayed onto the surface of the material by spraying. Then the coil was placed horizontally on a special tower-shaped convex coil tray by a coil turning machine (the tower shape was 2 mm, the sleeve was supported on the tray, the tray tower surface was vertically upward, the side of the sleeve on which the coil was coiled was vertically downward, and there was a gap between the tray tower surface and the coil).

[0026] During the cover annealing of the copper alloy strip, the following method was adopted: a special tower-shaped (the core was convex, and the tower shape was 2 mm) cover furnace annealing coil tray made of 309S stainless steel was used to load the coil, the tray was placed below, and the tower surface was in contact with the coiled strip; it was hoisted to the furnace table area for heat treatment at a temperature of 450°C, and a heating rate of 40-60°C / h was given during the heating stage; during the cooling stage above 200°C, the inner liner was air-cooled, and the cooling rate was 35-45°C / h; during the cooling stage below 200°C, the inner liner was water-cooled, and a cooling rate of 15-30°C / h was given. After annealing, there was also a gap between the tray tower surface and the coil.

[0027] The coiled strip of Example 2 was unwound and washed on a washing line without any obvious deformation at the edge of the coil, and no edge sticking occurred during unwinding.

Claims

1. A method for preventing blocking of copper alloy strip for use in batch annealing, characterized by: 50%~70% of the deformation processing rate is given before annealing, then the rolling process is distributed in a step-by-step reducing way for not less than 4 passes, and the last pass rolling processing rate is controlled below 12%; the work roll uses a convexity of 0.015mm~0.05mm, the lower roll is flat, and the plate shape control strategy is middle wave; the transverse difference of the product is controlled below 1% of the thickness size, and the two side differences are controlled below 0.5% of the thickness size by controlling the bending force and adjusting the deviation; Before the copper alloy strip is annealed in a hood, the strip is re-coiled, specifically as follows: a step-by-step coiling tension is used in the re-coiling process, that is, the coiling tension is gradually increased by 1~3N / mm2 at 3~4 equal parts of the coil; the coil is coiled on a steel sleeve; During the re-coiling process, the mineral oil with viscosity ≤ 10 mm 2 / s is sprayed to the surface of the material by spraying method. When the copper alloy strip is annealed in a hood, the following methods are adopted: a tower-shaped hood furnace annealing coil loading tray is used to load the coil, and the tray is placed below; a temperature rising rate of not more than 80℃ / h is given in the heating stage; a cooling rate of not more than 50℃ / h is given in the cooling stage above 200℃, and a cooling rate of not more than 30℃ / h is given in the cooling stage below 200℃.

2. A method of preventing blocking of copper alloy strip for use in batch annealing, according to claim 1, characterized in that: The sleeve width should be ≥coil width+15~30mm, and the coil edge is flush with the sleeve edge by 3~10mm.

3. A method of preventing blocking of copper alloy strip for use in batch annealing, according to claim 1 or 2, characterized in that: The tray tower shape is 2~5mm, when the coil is loaded, the steel sleeve is supported on the tower-shaped tray, the side of the sleeve where the coil is coiled is vertically downward, and there is a gap between the tray tower face and the coil; after annealing, there is a gap between the tray tower face and the coil.

Images