JPH0116285B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of heat-treating cutlery such as scissors, knives, and cooking utensils to produce cutlery having required strength and sharpness.

Conventionally, a high-energy beam such as a laser is irradiated onto the part of the cutter to be hardened, and at that time, the energy beam is focused on the surface of the cutter or at a desired depth, and is continuously scanned. A method has been used in which the surface of the workpiece is heated to the required temperature, and the heated part is cooled at an appropriate speed by controlling the scanning speed of the beam to provide the required strength and sharpness. . According to this method, the heat treatment is affected by the structure of the heated part of the workpiece and the melting state of the contained alloy components, so adjustment is required to appropriately obtain these changes. According to energy beam irradiation, the required heat treatment can be easily performed simply by controlling and projecting an energy beam with a constant power density. However, conventional processing methods simply irradiate the entire blade with a continuously scanning moving beam, and simply heat the entire blade at a constant temperature either in a straight line from one end to the other or in a strip of constant width in a perpendicular direction. It was discovered that sufficient effects could not be obtained because the treatment involved heating and cooling. In other words, even if the energy beam is applied at a constant intensity or at a selected intensity with changes appropriate to the part, simply increasing the hardness through continuous irradiation will not improve the cutting quality; Disadvantages were that the processing left distortions and the cutting edge was prone to spillage.

In view of the above-mentioned drawbacks, the present invention aims to provide a method for solving the problems of the conventional methods. To achieve this purpose, the method is characterized by a method in which the irradiation position of the high-energy beam is moved intermittently and discontinuously along the shaped blade of the cutter to form a hard and soft shape, thereby obtaining the required strength and sharpness. .

Next, the present invention will be explained by showing an example. An electron beam, ion beam, laser beam, or the like is used as the irradiation energy. The energy beam emitted from the energy generator (laser generator device in this case) 6 is bent by the prism 5, and the energy beam in the range between 4 and 14 is transferred to the lens 3.
The focal point 10 is focused inside the workpiece 1 near the surface as shown by the solid line 2. In this way, the focal point 10 of the surface of the workpiece to be irradiated is heated to the required temperature in a spotwise manner. In addition, if the irradiation position is moved to another location or the irradiation is interrupted, the workpiece will be cooled, and if the component metals of the workpiece are appropriately taken, they will be hardened by air cooling. Depending on the component, it is hardened by rapid cooling after heating. Also, by moving the lens 3, the dotted line 12
The focal point 20 can also be placed inside the workpiece as shown in FIG. In this way, a circular heating part with a fairly wide area is formed on the surface and the deep part is heated to the required temperature.

In this way, the focal spot 2 as shown in FIG.
2 heating surfaces are formed. In the present invention, as shown in FIG. 2, the focal spot is moved and irradiated in an intermittent and discontinuous manner to form a discontinuous heating section 22, and heating is not performed in a continuous line or a wide band. 3rd A
The figure shows a part of a scissor blade and shows typical intermittent and discontinuous heating spots, and FIG. 22 is formed. FIG. 3C shows a double-edged knife, with one blade forming discontinuous heating spots 22 that are relatively closely spaced, and the other blade forming intermittent heating spots 22 that are spaced apart. The following conclusions were obtained from the results of these series of experiments.

In these test knives, the diameter t ₁ of one heating circular portion 22 is suitably about 5 to 30 microns;
In many cases, 10 microns is preferred, and the spacing _t2 between these heating spots can be arbitrarily selected depending on the purpose of use.

The heated part 22 is hardened, and the unheated part (between the heating spots) remains soft, so hard and soft parts exist alternately along the cutting edge, and with use or polishing, it can be strengthened. Highly hard parts and soft but highly tough parts alternately compensate for good tempering, and as the soft parts wear out, unevenness occurs, creating a wavy pattern, and the edge of the blade is not in a straight line, increasing sharpness. In addition, distortions caused by heat treatment, final polishing, etc. are absorbed by the untreated portions between the heating spots, and processing can be performed without leaving any distortions, resulting in a sharpening process with high toughness. Although the cutting edge 11 in FIG. 3B shows a portion 22 that has been subjected to intermittent heating in relatively close proximity, care should be taken to avoid brittleness. This is done by selecting the spot spacing and spot diameter according to the alloy composition of the cutter.

Next, one applied example will be described. It is best to heat the entire blade portions 1 and 11 to a relatively low temperature of about 200 to 400°C to remove internal strain and perform internal diffusion to homogenize, and then perform the above-mentioned intermittent and discontinuous spot heating. There are cases. In addition, it is recommended to perform intermittent heating not in one direction continuously, but for example, to perform it one by one, then return and advance one by one, or to perform it at zigzag intervals to eliminate deformation and reduce the generation of internal strain. It has the effect of preventing

As another example of application, in order to strengthen the hardening in the part that undergoes intermittent heating, we use WC, cBN, etc. on the blade part.
When powder for diffusion such as TiN, WMoC, etc. is spread to a thickness of approximately 10 to 100μ and the intermittent energy is applied as described above, these will diffuse or fuse into the base material and increase its strength. It can increase hardness and sharpness.

As another example of application, a fine wire cutter can be obtained by winding a thin stellite wire around the outer periphery of a heat-resistant and acid-resistant metal wire, such as stainless steel wire, fusing the contact points of both wires, and then subjecting the wires to the intermittent heating described above.

The intermittent hardened cutter thus manufactured has good sharpness, can be given appropriate strength and hardness, has very little internal stress, naturally forms unevenness, and has good durability. It has the advantage of being easy to manufacture and requires less labor and cost.

[Brief explanation of drawings]

FIG. 1 is an exemplary front view of the energy irradiation device. FIG. 2 shows an intermittent irradiation portion of an embodiment of the present invention. 3rd A
Figures 3B and 3C are partial views of the intermittent treatment of the blade part, which is an application of the present invention applied to a cutlery. DESCRIPTION OF SYMBOLS 1, 11... Workpiece blade part, 2, 12... Irradiation energy focusing part, 4, 14... Irradiation energy flux, 5
... Prism, t ₁ ... Heating spot diameter, t ₂ ... Heating spot spacing, 22... Heating spot, 10,
20... Beam illumination point, 21A, 21B... One side or the other side of the workpiece.

Claims (1)

[Claims] 1. In the refining treatment of cutlery in which a high-energy beam is irradiated to the surface or a required depth of the metal heat-treated object, the high-energy beam generated from the high-energy beam generator is applied to the surface or the required depth of the refining part of the cutter. The irradiation point is focused on the blade, and the irradiation position is moved intermittently and discontinuously along the blade, and the tempered part is heated to the required temperature and cooled to make the hardened part discontinuous. A method for processing cutlery characterized by attaching a formed blade.