JPS62164831A - Slit strain relief annealing method - Google Patents

Abstract

PURPOSE:To enable efficient and uniform stress relief annealing of many thin sheet-like metallic bars while preventing the contact with each other by applying adequate tension to the metallic bars in a parallel state at adequate intervals and blowing a convectional heating gas thereto from above and below at an adequate blowing rate. CONSTITUTION:The many thin sheet-like metallic bars respectively having 0.15-0.25mm thickness are supplied from an un-coiler 1 and are passed in the parallel and tense state through an annealing furnace consisting of a heating furnace 7 and a cooling chamber 8, where the metallic bars are subjected to stress relieving by heating and cooling. The metallic bars are thereafter coiled on a coiler 21. The spaces between the adjacent metallic bars 2, 2... in the heating furnace 7 are set at about 10mm. The gas for convectional heating is blown from nozzles 12 of a chamber 11 in the heating furnace 7 toward the metallic bars 2 at <=15m/sec blowing rate and >=1kg/mm<2> tension is applied thereto by tensioners 5, 19. The lateral moving sizes of the metallic bars 2 are thereby maintained respectively at 5mm and the injuries of the bars 2 by the contact with each other is effectively prevented.

Description

[Detailed description of the invention] The present invention aims to solve the following problems.

(Industrial Application Field) The present invention relates to a slit strain relief annealing method for removing processing strain (7) on a metal strip slit into narrow widths.

(Prior Art) When performing strain relief as described above, a radiant heating method using a matsufuru has conventionally been used. That is, a method is used in which a plurality of metal strips are passed in parallel inside the matshuuru, and in the process, they are radiantly heated by a heat source outside the matshuuru.

However, in such cases, when the furnace temperature is raised above the predetermined strain relief temperature in order to shorten the furnace length, the difference between the temperature of the metal strip and the furnace temperature (thermal head) is large, so each metal strip There was a problem in that there were variations in the temperature reached and variations in product quality. If the thermal head was made smaller in order to eliminate the above-mentioned problem, the radiation heating ability for the metal strip would be reduced, which posed the problem of requiring a longer furnace length.

(Problems to be Solved by the Invention) This invention eliminates the above conventional problems and shortens the length of the heating furnace by using a convection heating method in which heating gas is sprayed onto the metal strip to heat it. It is possible to homogenize the product quality of a large number of metal strips, and even when gas is sprayed onto a large number of metal strips in parallel, the vibration of each metal strip can be minimized and the mutual interaction between them can be minimized. An object of the present invention is to provide a slit strain relief annealing method that can prevent damage to a metal strip due to contact with the metal strip.

The configuration of the present invention is as follows.

(Means for Solving the Problems) The present invention takes the measures as described in the claims above, and its effects are as follows.

(Function) A large number of metal strips are passed in parallel to the heating furnace. During this process, convection heating gas is blown onto the metal strip from above and below, thereby heating the metal strip.

(Embodiments) The drawings showing the embodiments of the present application will be explained below. 1 to 3, the unwinding device 1 has a large number of slits (for example, 12 to 16
) are wound in parallel. The above metal strip 2
is a copper alloy such as 42Ni alloy or phosphor bronze used in IC lead frames and the like. Also, its thickness is 0.15
~0.25 m, and the width is, for example, about 20 to 25 cranes. A large number of the metal strips are unwound in a parallel state from the unwinding device 1, passed through the guide rolls 3, and sent to the degreasing device 4, where they are degreased. The metal strip 2 that has passed through the degreasing device 4 passes through a tension applying device 5 on the front stage side and reaches an annealing furnace 6.

The annealing furnace 6 consists of a heating furnace 7 and a cooling chamber 8, and the metal strip 2 passes through a sealing roll provided in the heating furnace 7 and reaches its interior. In the heating furnace 7, chambers 11, 11 are disposed inside the furnace body 10 above and below the locus of passage of the metal strip 2 therebetween. The chamber 11 has a large number of nozzles 12 for spraying convection heating gas onto the large number of metal strips 2 . The furnace body 10 is equipped with a heater 16 for heating the gas and a fan 14 driven by a motor 15. A fan 14 is connected to the chamber 11 via a duct 13.

With these configurations, the gas heated by the heater 1G is sent to the chamber 1 via the duct 13 by the fan 14.
1 and is sprayed from the nozzle 12 of the chamber 11 toward the metal strip 2. Metal strip 2 entering heating furnace 7
is heated to a predetermined strain relief temperature (for example, about 650° C. in the case of 42Ni alloy, and about 320 to 350° C. in the case of phosphor bronze) by spraying the convection heating gas as described above. The heated metal strip then passes into a cooling chamber 8 where it is cooled in a well-known manner. The metal strip 2 that has been cooled is sent out from the cooling chamber 8 through a sealing roll 18, passes through a tension applying device 19 on the downstream side, a guide roll 20, etc., and is wound up by a winding device 21. The cooling chamber 8 may be constructed in the same manner as a cooling chamber in a well-known annealing furnace, or may be constructed with a gas blowing chamber in the same manner as the heating furnace 7.

When strain relief annealing is performed on the metal strip 2 as described above,
In the annealing furnace 6, a large number of metal strips 2 are arranged such that, for example, one
It will be around 0 dragons. Further, inside the annealing furnace 6, tension is applied to each metal strip 2 in the traveling direction of the metal strip 2 by the pair of tension applying devices 5. In this case, the tension applied to the metal strips and the gas from the nozzle 12 are applied so that each metal strip 2 causes lateral movement in the annealing furnace 6 and does not cause adjacent metal strips 2 to come into contact with each other. The blowing speed is set appropriately. That is, the tension is set to, for example, 1 kg/an'' or more, and the gas blowing speed is set to, for example, 15 m/sec or less so that the horizontal movement dimension of each metal strip is 4 to 61 m or less.

Next, Figure 4 shows an example of the relationship between the gas blowing velocity (nozzle flow velocity) in the furnace and the meandering amount of the metal strip.Graph A shows the tension (unit tension) of the metal strip as l kg.
This shows the above relationship when /m2. This graph shows that by setting the tension to 1 kg/am or more and setting the blowing speed from the nozzle 12 to 15 m/sec or less, the meandering amount of the metal strip can be kept to about 5 mm or less. When the tension is smaller than the above value, the relationship between the nozzle flow velocity and the meandering amount of the metal strip tends to be as shown in graph B, while when the tension is large, the relationship is as shown in graph C. However, if the nozzle flow rate is extremely low, the heating effect on the metal strip will decrease, and if the tension is too high, quality problems such as elongation will occur in the metal strip.To avoid these problems, the nozzle flow rate and It is best to determine the tension value.

Next, an example is as follows.

(a) Material 42N i alloy 0.25 "'X20"' X12 strips x 12.5m/s
In-furnace temperature 700°C Material temperature 650°C Heating length using conventional method Temperature deviation of each strip using convection heating method 650°C ± 2.5°C Temperature deviation of each strip using conventional method 650°C ± 5°C (b) Material Phosphor bronze 0.25 '@' x 20”' x 12 strips x 18
m/+iin Furnace temperature 400°C Material temperature 350°C Heating length in conventional method (effects of the invention) As described above, in the present invention, the metal strips 2 that are passed through the heating furnace 7 in parallel are heated. In this case, each metal strip 2 is heated by being blown with gas, so firstly, each metal strip 2 can be quickly heated to the required temperature in a short period, and the length of the heating furnace 7 can be shortened. effective. Secondly, it is possible to reduce the deviation in the heating temperature of the metal strips 2 arranged in the width direction, thereby making their quality uniform.

Moreover, in the above case, even if a large number of metal strips 2 are passed in parallel to the heating furnace 7, the distance between them is set at around 10 mm, so the number of strips that can be passed through the heating furnace of a predetermined width is limited. This has the effect of making it possible to use the heating furnace more efficiently.

Moreover, in the above case, each metal strip 2 is sprayed with gas, and the distance between the metal strips 2 is narrow, about 10 m, so that if the metal strips 2 vibrate due to the sprayed gas, they will mutually Even if there is a risk of entanglement, the blowing speed of the gas for convection heating from above and below shall be 15 m/sec or less so that the lateral movement of each metal strip in the heating furnace is 5 or less. and the above tension is 1kg/m
``Because of the above-mentioned provisions, it is possible to minimize the meandering caused by the lateral movement of each metal strip, prevent the metal strips from coming into contact with each other, and prevent the quality of the product from deteriorating due to scratches on the metal strips. be.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a diagram showing the entire strain relief annealing line, FIG. 2 is a longitudinal cross-sectional view of the heating furnace, and FIG.
The figure is a longitudinal sectional view showing the arrangement relationship between the metal strip and the nozzle in the chamber, and FIG. 4 is a graph showing the relationship between the gas blowing speed and the meandering amount of the metal strip. 2... Metal strip, 7... Heating furnace, 12... Nozzle. Figure 1 Figure 2 Figure 3/l Figure 4

Claims (1)

[Claims] Each thickness is 0.15 to 0.25 mm for the inside of the heating furnace.
A large number of metal strips in the form of thin plates are connected in parallel to each other, and each metal strip is stretched in a tensioned state by a tension applied in the direction of movement of each metal strip, and in the process, the large number of metal strips are heated. In the slit strain relief annealing method, the distance between adjacent metal strips is set at around 10 mm in the heating furnace, and each metal strip is heated by convection from above and below in the heating furnace. Each metal strip was heated by spraying gas for the purpose, and the lateral movement dimension of each metal strip in the heating furnace was 5 mm.
In order to achieve the following, the blowing speed of the gas for convection heating from above and below is determined to be 15 m/sec or less, and the above tension is set to 1.
A slit strain relief annealing method characterized in that the annealing is set at kg/mm^2 or more.