JP6953465B2 - Titanium copper foil and titanium copper foil manufacturing method - Google Patents

Description

The present invention relates to a titanium copper foil and a method for producing a titanium copper foil.

An electronic component called an autofocus camera module is used for the camera lens portion of a mobile phone. The autofocus function of a mobile phone camera is based on the spring force of the material used in the autofocus camera module, which moves the lens in a certain direction, and the electromagnetic force generated by passing a current through the coil wound around it. Move the lens in the direction opposite to the direction in which the spring force of the material works. The camera lens is driven by such a mechanism to exhibit the autofocus function (for example, Patent Documents 1 and 2).

For the autofocus camera module, a Cu—Ni—Sn-based copper alloy foil having a foil thickness of 0.1 mm or less and a tensile strength of 1100 MPa or more or a 0.2% proof stress has been used. However, due to recent demands for cost reduction, titanium copper foil, which has a relatively lower material price than Cu—Ni—Sn-based copper alloy, has come to be used, and the demand for it is increasing.

Japanese Unexamined Patent Publication No. 2004-2803 JP-A-2009-115895

Titanium copper foil is commercialized in the form of a coil, and various treatments and processing are performed on the titanium copper foil (for example, plating treatment, slit processing, etching processing, and bonding of surfaces to each other with other members. Processing or joining processing, etc.). These processes and processes are performed by using an unwinding device, a processing device, a processing device, a winding device, and the like. In the production line including these devices and other devices, the titanium copper foil continuously passes through each device via the guide roll.

Titanium copper foil is required to have various characteristics. For example, properties that can be easily processed and processed are required. In addition to this, a characteristic that allows the line to pass through the line without any trouble is required. Problems when passing through the line include the occurrence of wrinkles and scratches.

An object of the present invention is to provide a titanium copper foil capable of reducing the occurrence of wrinkles and scratches on a line.

Generally, it is preferable that the copper foil such as titanium copper foil is flat. However, the inventor has found that a titanium copper foil that can pass through a line without defects even if it is not flat, or a titanium copper foil that lacks a certain degree of flatness, can pass through a line without defects rather than a completely flat one. ..

The present invention has been completed based on the above findings and includes the following inventions in one aspect.
(Invention 1)
It is a titanium copper foil and has a medium-high ratio of 0.01 to 1.20%.
The elongation rate (I-Unit) of the central part is 1 to 60,
The titanium copper foil.
(Invention 2)
The titanium copper foil of the first invention, wherein the elongation rate (I-Unit) of the end portion is 1 to 60.
(Invention 3)
The titanium copper foil of Invention 1 or 2.
Ti is 1.5 to 5.0% by mass,
A total of 0 to 1.0% by mass of one or more selected from Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr.
Contains,
The balance consists of Cu and unavoidable impurities,
The titanium copper foil.
(Invention 4)
The titanium copper foil according to any one of the inventions 1 to 3, wherein the titanium copper foil has a tensile strength of 1100 MPa or more.
(Invention 5)
A method for producing the titanium copper foil according to any one of the inventions 1 to 4.
The method includes a step of pickling and a step of finish cold rolling.
The pickling includes pickling in a range where the spray pressure reduction rate (%) in the central portion in the width direction is 0 to 60%.
The finish cold rolling is the method including rolling in a range where the work roll crown amount (%) is 20 to 45%.
(Invention 6)
The method of invention 5,
The finish cold rolling includes rolling in a range where the intermediate roll shift amount (%) is 5 to 30%.
The method.

On one side, the medium-high ratio of titanium-copper foil is 0.01 to 1.20%. Further, the elongation rate (I-Unit) of the central portion is 1 to 60. This makes it possible to prevent the occurrence of wrinkles and scratches. Further, in another aspect, the elongation rate (I-Unit) of the end portion is 1 to 60. This makes it possible to prevent damage to the guide roll and fluttering of the copper foil.

In one embodiment, various dimensions related to the medium and high ratio of titanium copper foil are shown. The definition of the growth rate is shown.

Hereinafter, specific embodiments for carrying out the present invention will be described. The following description is for facilitating the understanding of the present invention. That is, it is not intended to limit the scope of the present invention.

1. 1. Titanium Copper Foil In one embodiment, the present invention relates to a titanium copper foil. The titanium copper foil is a copper foil containing copper as a main component and containing titanium. In one embodiment, the titanium copper foil has at least the following characteristics.
・ Medium and high rate is 0.01 to 1.20%
・ The growth rate (I-Unit) of the central part is 1 to 60.
The above features and other features will be described in detail below.

1-1. Dimensions Titanium-copper foil is commercialized in the form of a coil as described above, and the dimensions include thickness and width. The width is not particularly limited and may be 200 to 700 mm. Further, the thickness is 0.100 mm or less (preferably 0.050 mm or less) because it is called a titanium copper "foil". The thickness described here (that is, a thickness indicating the characteristics of the entire titanium copper foil) means the thickness of the central portion in the width direction. The lower limit of the thickness is not particularly limited, but typically may be 0.020 mm or more.

1-2. composition

In one embodiment, the titanium copper foil contains 1.5 to 5.0% by mass of titanium (preferably 2.0 to 4.0% by mass). When it is 1.5% by mass or more, a desired tensile strength can be realized. On the other hand, if it exceeds 5.0% by mass, the strength is too high and processing becomes difficult.

As elements other than the above, one or more of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr are further added in an amount of 0 to 1.0% by mass in total. It may or may not be added (for example, it may be 0% by mass). By adding these elements, among the mechanical properties such as hot workability in manufacturing, proof stress, tensile strength, spring limit value and stress relaxation property in products, and surface properties such as soldering properties and plating properties in products. The effect that any one or more becomes good can be obtained. If it is added too much, processing becomes difficult. Therefore, 0.005 to 0.6% by mass can be preferably added.

In one embodiment, the rest other than the above may be Cu. Here, unavoidable impurities may be contained in addition to the Cu. Examples of unavoidable impurities include S and O. The content of unavoidable impurities is not particularly limited, but is, for example, 100 mass ppm or less in total.

1-3. Medium-high rate The term "medium-high rate" in the present specification is defined as follows. Specifically, middle and high schools are as described in JIS H0500 "Terms of copper products" (2018). Then, the medium-high rate is defined as follows.
・ ((Thickness at the center-Thickness at the end) / Thickness at the end) x 100%

Here, each dimension is defined as follows (see FIG. 1).
-End thickness: A point on a straight line extending from one end to the other end in the width direction on the titanium copper foil surface, the thickness at the point where the dimension from one end is 1/10 W, and the dimension from one end is 9/10 W. Average value with thickness at a certain point ・ Thickness at the center: A point on a straight line extending from one end to the other end in the width direction on the titanium copper foil surface, and the thickness / width direction at the point where the dimension from one end is 1 / 2W. : Direction and width perpendicular to the rolling direction on the copper foil surface: Dimensions of a straight line drawn in the width direction on the copper foil surface from one end to the other end (W)

The titanium copper foil having a high medium-high ratio has a shape in which the thickness of the central portion is larger than the thickness of the end portion. Due to the large thickness, the central part is relatively stronger than the end part. Therefore, the titanium-copper foil having a high medium-high rate is less likely to cause wrinkles in the central portion when the titanium-copper foil is held by the guide roll when passing through the line.

On the other hand, if the thickness of the central portion is larger than the thickness of the end portion, the central portion will come into contact with the guide roll with a higher pressing force than the end portion, and scratches due to contact with the guide roll are likely to occur. Become.

The preferred range of medium and high rates is 0.01 to 1.20% (preferably 0.50 to 0.70%). If it is less than 0.01%, wrinkles are likely to occur in the central part. On the other hand, if it exceeds 1.20%, scratches are likely to occur in the central portion.

1-4. Growth rate (I-Unit)
Elongation rate is a measurement of "steepness and elongation rate (also referred to as elongation difference rate)" that is widely and generally used when evaluating the flatness of cold-rolled steel strips or copper and copper alloy plates and strips. according to. In one embodiment, as shown in FIG. 2, the Kobe Steel Technical Report (Vol. 59, No. 3: December 2009) is referred to.
The terms in the above are understood herein as follows.
Flatness: Flatness Stepness: Steepness λ: Steepness Elongation: Elongation difference rate = Elongation rate I-Unit: Elongation difference rate = Elongation rate δ: Wave height due to elongation difference L: Wave length due to elongation difference ΔL: Growth difference

Regarding the elongation rate measured as described above, the elongation rate at the central portion and the end portion is defined as follows.
-Elongation rate of the end: The region from one end to the other end in the width direction on the copper foil surface, the region where the dimension from one end is 0 / 4W to 1 / 4W, and the dimension from one end is 3/4W to 4 Maximum value of elongation in the combined region with / 4W ・ Extension in the center: The region from one end to the other end in the width direction on the copper foil surface, and the dimension from one end is 1 / 4W to 3 Maximum growth rate in the region of / 4W Here,
-Width direction: Direction perpendicular to the rolling direction on the copper foil surface-Width: Dimensions of a straight line drawn in the width direction on the copper foil surface from one end to the other end (W)

The titanium copper foil having a high elongation rate at the end has a slack shape at the end. With the slack shape, when the titanium copper foil is held by the guide roll when passing through the line, the pressing force generated between the guide roll and the titanium copper foil becomes small. Therefore, the titanium copper foil having a high elongation rate at the end is less likely to be damaged by the guide roll due to contact with the most advanced end.

On the other hand, if the end has a slack shape, the leading edge of the end is open, so that fluttering is likely to occur.

The preferred range of edge elongation is 1-60 (I-Unit). If it is less than 1 (I-Unit), the slack shape is insufficient, and the guide roll is likely to be damaged. On the other hand, if it exceeds 60 (I-Unit), fluttering is likely to occur because the slack shape is excessive.

The titanium copper foil having a high elongation rate in the central portion has a slack shape in the central portion. With the slack shape, when the titanium copper foil is held by the guide roll when passing through the line, the pressing force generated between the guide roll and the titanium copper foil becomes small. Therefore, the titanium copper foil having a high elongation rate in the central portion is less likely to have scratches in the central portion.

On the other hand, if the central portion has a slack shape, the central portion may be located at a portion constrained by the end portions on both sides, and wrinkles are likely to occur in the central portion.

The preferable range of the elongation rate in the central portion is 1 to 60 (I-Unit). If it is less than 1 (I-Unit), scratches are likely to occur because the slack shape is insufficient. On the other hand, if it exceeds 60 (I-Unit), wrinkles are likely to occur because the slack shape is excessive.

1-5. Tensile strength (tensile strength in the direction parallel to the rolling direction)
Further, in a preferred embodiment, the titanium copper foil has a tensile strength of 1100 MPa or more (more preferably 1300 MPa or more). As a result, the required specifications for use in a camera module or the like can be satisfied. The upper limit is not particularly limited, and may be, for example, 2000 MPa or less, and typically 1600 MPa or less.

2. Method for Producing Titanium Copper Foil Generally, in order to produce titanium copper foil, raw materials such as electrolytic copper and Ti are first melted in a melting furnace to obtain a molten metal having a desired composition. In some cases, the raw materials for the additive elements may be further dissolved together.

Then, this molten metal is cast into an ingot. Melting and casting are preferably carried out in vacuum or in an inert gas atmosphere to prevent titanium from being consumed by oxidation. After that, the ingot is typically subjected to hot rolling, first cold rolling, solution treatment, pickling, second cold rolling, aging treatment, finish cold rolling, and rust prevention treatment in this order. And finish the foil with the desired foil thickness and properties.

Conditions known in the art can be adopted for each of the above steps. However, for pickling and finish cold rolling, the titanium copper foil having the above-mentioned characteristics can be obtained by adopting the following conditions.

2-1. Pickling pickling is one of means for adjusting the preferred range mid-high ratio as described above. For example, it can be controlled by adjusting the pickling thinning amount at the end portion and the center portion in the pickling step.

In the pickling step after the solution treatment, the spray pressures of a plurality of spray nozzles evenly arranged at equal intervals in the width direction and the longitudinal direction of the solution treatment material are adjusted. Specifically, the wall thickness is reduced by pickling as expressed by the following formula for the central part and the end part (for the definition of the central part and the end part, as described in "1-3. Medium-high rate"). Adjust the uniformity.
-Spray pressure reduction rate at the center = ((spray pressure at the edge-spray pressure at the center) / spray pressure at the edge) x 100%

When the spray pressure reduction rate in the central portion is 0%, the ability of thinning by pickling is equal between the central portion and the end portion. When the spray pressure reduction rate in the central portion is negative, the central portion has a higher ability to reduce the thickness by pickling than the edge portion. When the spray pressure reduction rate in the central portion is a positive value, the ability of the central portion to reduce the thickness by pickling is lower than that in the end portion.

However, in reality, even when the spray pressure reduction rate in the central portion is 0%, the medium-high rate does not become 0% and may show a positive value. Although it is considered that the cause is other than the spray pressure, a good correlation is shown between the spray pressure reduction rate in the central portion and the medium-high rate, and there is no significant influence on the implementation of the invention.

2-2. Finish cold rolling For controlling the elongation at the center and edges, use the well-known shape control means used in finish cold rolling when manufacturing steel or copper and copper alloy plates and strips by cold rolling. It may be used.

Many technologies have been put into practical use as shape control means by a rolling mill, for example, roll bending, roll dimensional shape (taper, crown), roll shift, roll cloth, variable crown roll (VC roll, etc.), backup bearing. There are technologies such as extrusion pattern change (20-stage and 12-stage cluster rolling mills), rolling down leveling, and asymmetric roll bending.

The means for carrying out the present invention is not particularly limited, and any means for adjusting the shape of the metal plate in cold rolling of the metal plate can be selected. However, since it is necessary to control two variables regarding the elongation rate of the central portion and the end portion, it is necessary to select at least two or more means as the means for adjusting the shape.

Here, as an example, the crown amount of the work roll and the shift amount of the intermediate roll will be described.

2-2-1. Work roll crown amount

For work rolls, the crown shape is adjusted by roll grinding, and rolls with different crown shapes are used. Here, the work roll is adjusted so that the roll diameter at the center portion in the longitudinal direction of the roll is larger than the roll diameter at the edge portion in the longitudinal direction of the roll, and the amount is referred to as a crown amount.

First, as a preliminary test, in the final pass of cold finishing cold rolling, a work roll in which the amount of crown was gradually increased was used, and the presence or absence of fracture was confirmed. As the amount of crown is increased (that is, when the roll diameter at the center in the longitudinal direction of the roll is made larger than the roll diameter at the end in the longitudinal direction of the roll), the titanium copper foil is broken. The amount of crown at this time is 100%.

By adjusting the amount of crown, the elongation rate of the central portion of the titanium copper foil can be adjusted. When the amount of crown is small, the elongation rate of the central part is low, and when the amount of crown is large, the elongation rate of the central part is high. For this reason, the crown amount is adjusted to 20-45% (preferably 20-40%).

2-2-2. Shift amount of intermediate roll The intermediate roll uses a tapered roll, and a roll shift is possible. The tapered roll includes a tapered portion and a flat portion. The taper portion has a smaller roll diameter than the flat portion. Therefore, the reduction from the intermediate roll to the work roll is reduced at the portion where the tapered portion of the intermediate roll is in contact with the work roll. The intermediate roll is arranged so that the tapered portion is applied to the end portion of the titanium copper foil. By changing the roll shift position of the intermediate roll by the roll shift, the position of the tapered portion is also changed, and the effect of the taper, that is, the reduction from the intermediate roll to the work roll is adjusted.

First, as a preliminary test, the roll shift position of the intermediate roll was gradually changed, and the presence or absence of breakage was confirmed. The roll shift amount was set to 100% at a predetermined position where the taper had no effect, and no breakage occurred here. Next, when the roll shift position was gradually changed in the direction in which the effect of the taper became large, that is, when the taper portion was increased over the titanium copper foil, the titanium copper foil broke. The roll shift amount was set to 0% at the roll shift position at the time of breaking.

By adjusting the roll shift amount, the elongation rate of the end portion of the titanium copper foil can be adjusted. When the roll shift amount is small, the elongation rate of the end portion is low, and when the roll shift amount is large, the elongation rate of the end portion is high. For this reason, the roll shift amount is preferably 5 to 30% (more preferably 10 to 25%).

3. 3. Evaluation items (defects when passing through the line)
The presence or absence of defects in the passage of the titanium copper foil rewinding line was evaluated. Four evaluation items were adopted: wrinkles, scratches, guide roll damage, and fluttering.

Regarding the evaluation item "wrinkles", if wrinkles were visually observed while passing through the line, it was regarded as defective (x). Further, even if no unevenness was observed and a wrinkle-like pattern was observed, it was regarded as defective (x). And other than that was good (○).

The evaluation item "scratch scratches" was evaluated by the following procedure. Specifically, a metal guide roll was placed on the line. Then, the rotational torque of the guide roll was adjusted so that the peripheral speed of the guide roll was 80% of the passing speed of the titanium copper foil. That is, the speed of the titanium copper foil and the speed of the guide roll are not synchronized. Then, after passing through the line, the surface of the titanium-copper foil was visually observed, and the case where scratches were generated was regarded as defective (x). And other than that was good (○).

The evaluation item "guidance roll damage" was evaluated by the following procedure. Specifically, a rubber guide roll was placed on the line. Next, a tension corresponding to 60% of the tensile strength was applied to the titanium copper foil. Then, after the titanium copper foil passed through the line, damage to the guide roll was confirmed. The place where the edge of the titanium copper foil passed was observed, and the case where the surface of the rubber was scraped was regarded as defective (x). In addition, a defect (x) was also given when a passage mark was visually observed even if it was not scraped. And other than that was good (○).

The evaluation item "fluttering" was evaluated by the following procedure. Specifically, first, a guide roll was arranged. These rolls were placed at the same height in the vertical direction from the ground, and were placed so that the horizontal spacing was 3 meters. As the titanium copper foil passed between the pair of guide rolls, the tip of the edge was observed at the midpoint (ie, the distance between the two guide rolls was 1.5 meters). A case where the leading edge of the end vibrates greatly in the vertical direction is regarded as a defect (x). Here, when the operation of the line is stopped, the leading edge of the end does not vibrate. At this time, the tip of the end exhibits a wavy curve that repeatedly rises and falls in the vertical direction. A case where vibration of more than twice the height difference of the wave was observed during the operation of the line, that is, when the titanium copper foil was passing between the pair of guide rolls was regarded as defective (x). And other than that was good (○).

4. Production of Titanium Copper Foil An ingot was cast so as to have the composition shown in Tables 1 and 2. The ingot was processed to have the product thickness shown in Tables 1 and 2. Specifically, hot rolling, first cold rolling, solution treatment, pickling, second cold rolling, aging treatment, finish cold rolling, and rust prevention treatment were carried out in this order.

At the time of pickling, the spray pressure reduction rate (%) in the central portion in the width direction was adjusted to the conditions shown in Tables 1 and 2. Further, the intermediate roll shift amount (%) and the work roll crown amount (%) at the time of finish rolling were adjusted to the conditions shown in Tables 1 and 2.

By the method described above, the medium-high rate (%), the elongation rate at the edges, and the elongation rate at the center were measured. Further, the tensile strength was measured according to JIS Z2241-2011 (metal material tensile test method). In addition, wrinkles, scratches, damage to guide rolls, and fluttering were also evaluated. The results are shown in Tables 1-2.

In all of Invention Examples 1 to 23, the medium-high rate and the elongation rate in the central portion showed values in a preferable range. Then, in the subsequent rewinding test, wrinkles and scratches did not occur. Further, in Invention Examples 1 to 20 and 23, the elongation rate of the end portion showed a value in a preferable range. Then, in the subsequent rewinding test, no damage to the guide roll and no fluttering occurred. On the other hand, in Invention Example 21, since the intermediate roll shift amount in the finish cold rolling was too small, the elongation rate of the end portion was below the preferable range, and the guide roll damage occurred in the rewinding test. Further, in Invention Example 22, since the intermediate roll shift amount in the finish cold rolling was too large, the elongation rate of the end portion exceeded the preferable range, and fluttering occurred in the rewinding test. In Invention Example 23, the Ti concentration was too low, so the tensile strength was below the preferable range.

In Comparative Example 1, since the spray pressure reduction rate in the central portion in pickling after the solution treatment was too low, the medium-high rate was below the preferable range, and wrinkles were generated in the rewinding test.

In Comparative Example 2, since the spray pressure reduction rate in the central portion in pickling after the solution treatment was too high, the medium-high rate exceeded the preferable range, and scratches were generated in the rewinding test.

In Comparative Example 3, since the crown amount of the work roll in the finish cold rolling was too small, the elongation rate of the central portion was below the preferable range, and scratches were generated in the rewinding test.

In Comparative Example 4, since the crown amount of the work roll in the finish cold rolling was too large, the elongation rate of the central portion exceeded the preferable range, and wrinkles were generated in the rewinding test.

In Comparative Example 5, since the Ti concentration was too high, cracks were generated in the hot rolling, and the subsequent processing became impossible.

In Comparative Example 6, since the total concentration of each alloying element except Ti was too high, cracks were generated in hot rolling, and subsequent processing became impossible.

The specific embodiments of the present invention have been described above. The above-described embodiment is merely a specific example of the present invention, and the present invention is not limited to the above-described embodiment. For example, the technical features disclosed in one of the above embodiments can be applied to other embodiments. Further, unless otherwise specified, for a specific method, it is possible to replace some steps with the order of other steps, and an additional step may be added between the two specific steps. The scope of the present invention is defined by the claims.

Claims (6)

It is a titanium copper foil and has a medium-high ratio of 0.01 to 1.20%.
The elongation rate (I-Unit) of the central part is 1 to 60,
A the titanium copper foil,
here,
The medium-high rate is
((Thickness at the center-Thickness at the end) / Thickness at the end) x 100%
Calculated from the formula of
The thickness of the end portion is a point on the straight line extending from one end to the other end in the width direction on the titanium copper foil surface, the thickness at the point where the dimension from one end is 1/10 W, and the dimension from one end is 9 /. It means the average value with the thickness at the point of 10 W,
The thickness of the central portion means the thickness at a point on the titanium copper foil surface on a straight line extending from one end to the other end in the width direction, and the dimension from one end is 1 / 2W.
The elongation rate (I-Unit) of the central portion is the elongation rate in the region extending from one end to the other end in the width direction on the titanium copper foil surface, and the dimension from one end is 1/4 W to 3/4 W. Means the maximum value,
Titanium copper foil . The titanium copper foil according to claim 1, wherein the elongation rate (I-Unit) of the end portion is 1 to 60 .
here,
The elongation rate of the end portion is a region extending from one end to the other end in the width direction on the titanium copper foil surface, a region where the dimension from one end is 0 / 4W to 1 / 4W, and a dimension from one end is 3 /. It means the maximum value of the elongation rate in the region in which the region of 4W to 4 / 4W is combined.
Titanium copper foil . The titanium copper foil of claim 1 or 2.
Ti is 1.5 to 5.0% by mass,
A total of 0 to 1.0% by mass of one or more selected from Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr.
Contains,
The balance consists of Cu and unavoidable impurities,
The titanium copper foil. The titanium copper foil according to any one of claims 1 to 3, wherein the titanium copper foil has a tensile strength of 1100 MPa or more. The method for producing the titanium copper foil according to any one of claims 1 to 4.
The method includes a step of pickling and a step of finish cold rolling.
The pickling includes pickling in a range where the spray pressure reduction rate (%) in the central portion in the width direction is 0 to 60%.
The finish cold rolling is the method including rolling in a range where the work roll crown amount (%) is 20 to 45% .
here,
The work roll crown amount means a value when the crown amount is increased and the crown amount when the titanium copper foil is broken is 100%.
The spray pressure reduction rate at the center in the width direction is
Central spray pressure reduction rate = ((end spray pressure-central spray pressure) / edge spray pressure) x 100%
Calculated from the formula of
The spray pressure at the end is 1/10 W at a point on the straight line extending from one end to the other end in the width direction on the titanium copper foil surface, and the dimension from one end is 9/10 W. Means the average value with the spray pressure at the point
The spray pressure at the central portion means a spray pressure at a point on the titanium copper foil surface on a straight line extending from one end to the other end in the width direction and having a dimension of 1/2 W from one end.
Method . The method of claim 5.
The finish cold rolling includes rolling in a range where the intermediate roll shift amount (%) is 5 to 30%.
A method,
Here, the intermediate roll shift amount is 100% for the roll shift amount at a position where the taper has no effect, and 0% for the roll shift amount when the titanium copper foil is broken by changing the roll shift position. Means the value when
Method .

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