JPS62240112A - Strain straightening method for metal disk - Google Patents

Abstract

PURPOSE:To improve the straightening accuracy of the strain of a metal made disk by holding the metal made disk between plurally piling floor iron plates and pressing iron plate and by performing a heat annealing while applying a pressure via a heat resistant spring. CONSTITUTION:The metal made disk 2 punched annularly is piled up on a floor iron plate 1 and a pressing iron plate 3 is placed thereon. The prescribed pressure is then applied on the disk 2 by a spring force over the floor iron plate 1 and pressing iron plate 3, by pressurizing a heat resistant spring 8 from the upper end by a nut 5. The deflection straightening of the metal disk 2 is performed by performing the annealing for the prescribed time by heating it by inputting into a furnace in this state. There is the method of pinching a deflection straightened spencer 9 between piled up metal disks 2 as well. The metal disk 2 is taken to be of Al alloy made, etc., and the heat resistant spring 8 of tool steel SKD-4, etc. In this way the deflection straightening can be performed by a constant pressurizing force while under annealing and the flatness of high accuracy is obtainable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for correcting distortion in a metal disk punched into a ring shape, such as a magnetic disk made of an aluminum alloy. A punched metal disk made of aluminum alloy or the like is circumferentially distorted or radially bent due to the punching process, so it is necessary to correct these distortions.

Pressure annealing correction method is used to correct this distortion.
Conventionally, as shown in Fig. 2, a large number of punched ring-shaped metal disks (2) of the material to be straightened are stacked on a paving iron plate (1), a presser iron plate (3) is placed on top of the metal disks (2), and a pressing iron plate (3) is placed on top of the metal disks (2). Apply Nando (5) to the bolt (4) installed on both iron plates (1) +3)
In the meantime, the laminated disk (2) is charged into a heating furnace or the like while being pressurized and subjected to pressure annealing and straightening.

Alternatively, as shown in Figure 6, instead of bolts and nuts, use a heavy iron plate (6) of 50 to 200 kg to hold it down.
3) It is placed on top and pressurized. In some cases, a spacer (7) is placed between every ten or several tens of stacked disks to reduce the cumulative effect.

(Problem to be solved by the invention) In order to make a product with high precision flatness by straightening the distortion of a punched metal disk, it is necessary to apply pressure by bolts + 4), nuts (5) or heavily 6) during annealing. , it is important to keep it regular. However, in the conventional method shown in FIG. 2, the pressing force applied to the metal disk becomes unstable due to friction between the bolt and nut, friction between the nut and the presser iron plate, and the difference in thermal expansion between iron and aluminum alloy. In the method shown in Figure 3, the gravity of the weights is constant, so the pressure does not become unstable, but increasing the pressure due to the increase in the number of weights is restricted due to the heating furnace and processing capacity. It is necessary to take measures such as reducing the number of stacked disks. In either method, it is difficult to adjust the pressing force, and if too much weight is applied or the nut is tightened too much, the material starts to be compressed and becomes deformed. If the pressure applied to the reaction is insufficient, the distortion will not be corrected to a satisfactory degree.

(Means, actions, and embodiments for solving the problem) The problem with the prior art is that a heat-resistant spring that maintains elasticity at the annealing temperature and has a known elastic modulus is interposed, and the spring force applies pressure to the stacked metal disks. υM is determined by giving υM.

That is, the method for correcting distortion of a metal disk of the present invention has a structure in which, in order to correct the distortion of a metal disk punched into a ring shape, a plurality of the metal disks are stacked and a paving iron plate and a presser iron plate are stacked. The method is characterized in that heating and annealing is performed while holding the iron plate in between and applying pressure across the laying iron plate and the holding iron plate via a heat-resistant spring.

Hereinafter, the present invention will be specifically explained based on an example with reference to FIG. Each figure in FIG. 1 shows each method of applying pressure to a stack of metal disks in the method of the present invention.

In Figure 1 (a), bolts (4) are attached to the iron plate (1).
To install it, stack a plurality of metal disks (2) punched into a ring shape by fitting them into the bolts (4) on the iron plate (1), and place the presser iron plate (3) on top of them.

On top of that, fit the heat-resistant spring (8) onto the bolt (4), and tighten the nut (5) screwed into the upper end of the bolt (4).
) Apply pressure to the spring (8) from the upper end and bend it between it and the presser iron plate. In this way, the laying iron plate (1) and the pressing iron plate (
3), a predetermined pressure is applied to the stacked metal disks (2) by spring force via the spring (8), nut (5), and bolt (4). In this state, the metal disk is placed in a furnace, heated to an annealing temperature, and annealed for a predetermined time to straighten the distortion of the metal disk.

In the case of aluminum alloy discs, the annealing conditions are 360
℃ for about 5 hours. It is necessary to use a heat-resistant spring (8) that has sufficient resistance to this heating condition, for example, alloy tool steel SKD 4, is
% Made from Ni maraging steel, etc. By adjusting the height, the tightening force can be arbitrarily applied using a spring force suitable for the type and size of the metal disk.

FIG. 1(b) shows a modification of the assembled and pressurized state of the metal disk, in which a spacer (9) made of an aluminum disk whose distortion has been corrected by cutting is used. Spacers (9) are placed at the ends and in the middle of every 50 ring-shaped metal disks (2).
) to form a stacked state. Figure 1 (c)
shows another variant with one intermediate spacer (9).

A disk of aluminum alloy A, 50B6 with a diameter of 135.35 mm (51 inches) was used as the specimen, and Fig. 1 (a)
Strain correction was carried out in accordance with the above method.

Stack 250 discs and adjust the pressure to 400#.
The annealing conditions were a temperature filter of 60'C and a time of 5 hours. The results are shown in the table below.

The following table also includes the conventional techniques shown in FIGS. 2 and 5 for comparison. The numerical unit is μm.

As shown in the table, the distortion after distortion correction and the curvature in the diametrical direction are superior to those of the prior art, and the standard values are stably satisfied.

(Effects of the Invention) According to the strain straightening method of the present invention, the pressure applied to the metal disk can be easily changed and adjusted to the required value compared to the conventional technology, and a constant pressure is applied to the material to be straightened during annealing. Since the distortion can be corrected over the entire area, highly accurate flatness of the corrected product can be obtained.

[Brief explanation of drawings]

FIG. 1(a) is a side view showing one embodiment of metal diss stacking in the method of the present invention, FIG. 1(b) is a side view of a modified version thereof, and FIG. 1(c) is a side view of another modified version. figure,
FIG. 2 is a side view showing one example of a conventional disc stack, and FIG. 3 is a side view showing the other side of the prior art disc stack. (1)... Iron plate, (2)... Metal disk, (3)
... iron plate, (4) ... bolt, (5) ... oak)
, +6)・Weight, (7H9)・・Spacer, (8)
・・Heat resistant spring. Figure 1

Claims (2)

[Claims] (1) In order to correct the distortion of the metal disk punched into a ring shape, a plurality of the metal disks are stacked and held between a laying iron plate and a holding iron plate, and a heat-resistant spring is applied between the laying iron plate and holding iron plate. A method for straightening distortion of a metal disk, characterized by performing heating annealing while applying pressure through a metal disk. (2) A metal disk according to claim 1, wherein a strain-corrected spacer is sandwiched between a certain number of stacked metal disks to hold the metal disk between a laying iron plate and a pressing iron plate. distortion correction method.