JPH0220365B2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field: The present invention applies enameling to the surface of a stainless steel cutter and coats it with a thin layer of glass to enhance its decorativeness and further improve its corrosion resistance. The present invention relates to a manufacturing method for obtaining a product.

Background of the Invention: Although conventional cutlery such as kitchen knives have functional beauty, they exhibit a cold feel peculiar to cutlery.

However, considering the function of cutlery itself,
If the sharpness is good, there is no problem in practical use, but it is a problem in terms of decoration and corrosion resistance. Particularly when cooking highly acidic items, if you do not take care of them by washing them with water immediately, they will rust, impair the beauty of the knife, and reduce its sharpness. Furthermore, in recent years, kitchen utensils with various colors have been manufactured and put into practical use. For this reason, there is a tendency to prefer colored cutlery, and some have begun to propose cutlery with colored metal parts.

However, if the sharpness of a knife deteriorates, the blade must be sharpened to improve its sharpness and be used for a long period of time, so simple coloring is not preferable because it is only temporary.

In addition, stainless steel cutlery is in practical use as a cutter with corrosion resistance in mind. The materials used for this stainless steel knife are generally
SUS 420 (13% Cr, 0.3% C) and SUS 440 (16 to 18
%Cr, 0.25 to 1.25% C) are used (these are used for cutlery because they can be hardened to improve sharpness). Therefore, even when stainless steel is used, rusting is inevitable under adverse conditions during use, and the user still needs to clean it after use.

On the other hand, some corrosion-resistant stainless steel products are enameled mainly for the purpose of imparting decorative properties. However, in the conventional enameling process for stainless steel products, only the temperature necessary for firing the so-called steel plate enameling glaze is applied, so the relationship between the base material and the glaze is mainly concerned with the firing condition of the glaze. Therefore, it was possible to achieve the objective without paying too much attention to the thermal effects on the stainless steel base material.

In other words, in the conventional enameling process for stainless steel, the objective could be achieved by using a glaze with a relatively low melting point.

However, if we try to apply the conventional enameling process for stainless steel products to cutlery, since the baking operation temperature of conventional enameling glaze is 780-850℃, this temperature does not reach the quenching temperature, so the blade It is not possible to improve the sharpness of the blade. Therefore, it has been difficult to enamel stainless steel cutlery and obtain a practical product using the conventional technology.

Purpose of the invention: The present invention provides decorativeness to stainless steel cutlery and improves corrosion resistance by applying enameling processing, which has been difficult to perform in the past, and after firing, heat treatment such as quenching and tempering of the blade part is performed. Therefore, it is an object of the present invention to provide a method for manufacturing a stainless steel cutlery which is enameled without damaging the enameled layer.

Structure of the invention: The present invention involves first punching a stainless steel plate of a desired thickness, shaping it into a desired shape, processing it by sandblasting to make the surface rough, and then forming an oxidation-inhibiting layer on its outer surface. After going through the pre-treatment process, the expansion rate is adjusted and a high temperature stable glaze is directly applied once, the glaze is fired at the required temperature, then the painting and letters are added, and then quenching and tempering. This is a method of manufacturing stainless steel cutlery that has both decorative properties and corrosion resistance by processing and coating the surface with a glass layer.

Means for solving the problem: In the present invention, as a means to improve the adhesion of the glaze, forming irregularities on the surface of the base material using Sand Plus is similar to the conventional enameling process for stainless steel. However, in order to maintain the sharpness of knives, materials that are easy to harden (SUS 420, SUS
Since it uses chromium-containing martensitic stainless steel (such as 440), it is exposed to high temperatures exceeding 1000℃, which causes excessive oxidation of the surface and causes poor adhesion of the glaze. Therefore, to prevent this,
Forms an oxidation-inhibiting layer on the surface of the base material.

As a means for forming this oxidation-inhibiting layer, in addition to treating the base material by energizing it in an aqueous sulfuric acid bath, a nickel film is formed by electroplating, displacement plating, or the like.

The enamel glaze in the present invention is applied once directly to a base material that has been treated with an oxidation-inhibiting film. This enamel glaze is basically white glaze,
A required pigment is added to this to form a colored glaze. However, when adding a pattern, it is preferable to use a slightly colored tone to harmonize with the color of the pattern.

Furthermore, as a milky white glaze, ordinary enamel glaze for steel plates, such as titanium milky white glaze, zircon milky white glaze,
Antimony milky white glaze etc. However, titanium milky white glaze tends to take on a milky white color and has excellent acid resistance.
Color tone becomes unstable due to exposure to temperatures exceeding
You can't get something homogeneous. Zircon milky white glaze is inferior to titanium glaze in milky white coloration, superior to antimony glaze, and has excellent stability at high temperatures, but is unsuitable because its acid resistance is extremely low.

Although antimony milky white glaze is inferior in milky white coloration, it is excellent in milky white stability at high temperatures and acid resistance, and therefore a glaze based on antimony is used in the present invention. Furthermore, when the cutlery to be glazed is thick, a considerable temperature difference occurs between the enamel layer and the center of the base material during quenching during the quenching process. Therefore, good results can be obtained by mixing 10 to 30% white glaze, which is a low-temperature glaze for pottery with a low expansion rate. In addition, when using antimony glaze alone, it "shrinks" when melted at 1000℃ (the glaze applied to the article will shrink during firing).
This is a phenomenon in which the surface rises closer to the center than the periphery). Therefore, using this glaze as a base, small amounts of zirconium silicate, tin oxide, alumina, etc. are mixed in to supplement the opalescent color development and high-temperature stability.

To apply the glaze, use the same dipping or spraying methods as conventional methods, and apply it uniformly to the surface of the base material. In the case of cutlery such as kitchen knives, it is preferable to use a spraying method, which allows a thin layer to be applied almost evenly. The coating thickness is preferably 0.1 to 0.2 mm. Of course, it is not limited to this range.

In the present invention, in the case of a plain finish without painting by transfer or the like, the glaze is applied and then directly transferred to the quenching step, and the glaze is fired and the base material for the cutler is quenched at the same time. However, in order to take advantage of the enameling process and increase its decorative properties, the glaze is fired at a temperature of 800 to 900°C, depending on the composition of the glaze.

After the glaze is fired, room temperature transfer using transfer paper,
Desired designs and characters are painted (hereinafter referred to as designs and characters included) by heat transfer, screen printing, stamping, etc. Among the pigments usually used for painting,
Even if the color tone is stable at around 800℃, there are some that fade or discolor when the temperature exceeds 900℃. Therefore, it is preferable to protect the painted portion from the high temperatures during hardening, and the temperature rise in the painted portion is suppressed by covering the painted portion with a protective board. Note that in the case of no discoloration or fading, or in the case of a small amount of pigment, quenching may be performed without using a protective plate.

After painting, the pieces are directly transferred to the hardening process. This hardening is performed by a known method suitable for the material of the base material. At this time, the glaze can withstand hardening by adjusting the thickness of the glaze, the strength of its adhesion, and the expansion rate of the glaze. By the way, the quenching temperature for stainless steel cutlery is SUS
1000~1050℃ oil cooling for 420, 1010~1070 for SUS 440
°C oil cooling is a commonly employed heat treatment temperature.

After performing the quenching treatment in this manner, tempering is performed. This is also done by a known method adapted to the material of the base material. By performing this tempering treatment, the strain caused in the enamel layer due to rapid cooling is also removed. This tempering temperature is 150 for SUS 420.
-200℃, 150-200℃ for SUS 440, both by air cooling. By performing such tempering, the overall stability is achieved.

After the heat treatment is completed in this way, the blade is polished to expose the metal part and finished with a cutting edge.

The enameling of stainless steel in the present invention involves quenching treatment compared to conventional enameling of stainless steel, so the pretreatment and glaze composition are There is a big difference.

In particular, regarding the adhesion of the enamel layer, there is almost no difference at temperatures around 800°C, but at temperatures above 1000°C during quenching, oxidation of the base material progresses and the adhesion of the enamel layer deteriorates. In addition, stronger adhesion is required to withstand thermal shock during the subsequent rapid cooling. Therefore, in the present invention, a nickel plating layer is formed on the surface after sandblasting (or a similar processing method). This nickel film layer then suppresses oxidation of the base material and maintains adhesion.

Furthermore, since the glaze is exposed to high temperatures during quenching, the enamel layer used on conventional stainless steel could not withstand it, but by creating a glaze that can withstand high temperatures and using it, we were able to achieve our goals. was achieved.

Example: The method of the present invention will be described with reference to an example. 1st
What is shown in Figures and Figure 2 is a so-called Bunka knife, in which the base material 1 is SUS 440 (16-18%
A plate material containing Cr.0.25 to 1.25% C) is punched into a desired shape and pre-processed so that the blade portion 3 is thinner than the threaded portion 2. This is used as pre-treatment to roughen the parts other than the handle 4 by sand blasting to make the surface rough. Thereafter, a nickel film 5 is formed on the entire surface of the base material 1 by electroplating.
This nickel film 5 needs to be plated to an extent of 0.1 to 0.2 μm.

The knife base material 1 pretreated in this way is coated with a mixed glaze consisting mainly of antimony milky white glaze, with a total of 15 to 20% of zirconium silicate, tin oxide, alumina, etc. Coat the desired portion of the surface of the base material 1. This glaze is applied once directly to a uniform coating thickness of approximately 0.1 to 0.2 mm. In particular, care must be taken to prevent sagging and local thickening during application.

The glazed item is placed in a firing furnace at approximately 800-900℃.
Fire it with After firing, it is cooled and the design 11 is transferred to a required location using transfer paper. For this pattern, it is preferable to use a pigment that provides a good finish, taking into consideration the color development after firing.

After painting, the 11 parts of the pattern are covered with a protective plate made of bent stainless steel plate, placed in a heating furnace, and heated to about 1000°C. The heated material is taken out, placed in an oil bath, cooled in oil, and quenched. This operation is performed almost in the same way as general hardening.

It is then heated in a furnace to around 200℃ and left in the air to temper.

To remove distortion through this tempering process, the intermediate product obtained in the above manner (almost complete except for the cutting process) was placed on a hard floor (concrete floor) from a height of 80 cm. A drop test was conducted with the tip of the knife facing downward under the worst conditions. As a result, when the sharp tip was deformed, the enamel layer peeled off only in that area, but no abnormalities were found in other parts. From this, it was confirmed that the enamel layer was firmly attached and the internal strain was eliminated.

As described above, a kitchen knife having the enamel layer 10 formed on its surface is obtained. Therefore, the blade part 3 is polished so that about 1 to 2 mm of the base material is exposed, and the cutting edge 3'
Add and finish.

The knife thus obtained is a product in which the base material 1 and the thin enamel layer 10 are in close contact with each other, and the pattern 11 transferred to the outer surface having a milky white base color is clearly visible. The resulting knife has a smooth surface, except for the cutting edge, and is formed with a slightly uneven surface, which prevents the cut material from peeling off during cooking without sticking to it, causing problems. do not have. In addition, since the surface is hard, it is easy to wash off without being damaged by scrubbers etc.

As an acid resistance test, it was immersed in a 10% citric acid aqueous solution for 10 days and then taken out, but there was no change. In the process of selecting a glaze, a glaze made from a zircon milky white glaze with 10 to 20% alumina added had excellent color development and was elegant, but it had poor acid resistance, and a 10% citric acid aqueous solution After soaking for an hour,
The enamel layer has completely dissolved.

The above has described examples of kitchen knives, but even if the material is SUS 440, for example, the same thing as above can be obtained, and in addition to kitchen knives, small cutlery such as paring knives can also be made with similar beauty. I was able to get the product.

Therefore, in the case of cutlery without a blade, such as a paper knife, it is possible to obtain an effective product that also serves as a decoration.

Effects of the invention: According to the present invention, a cutlery, which conventionally only had a cold feel peculiar to cutlery, can be made highly decorative by applying colorful colors and designs, and it can completely impair its sharpness as a cutlery. This is a useful invention that makes it possible to obtain a product with improved corrosion resistance without requiring a lot of effort, and also allows for mass production without requiring much labor, which can be provided at a low price, and which can enhance hobby effects. You can say that.

[Brief explanation of drawings]

FIG. 1 is a front view of an example of a kitchen knife obtained by the method of the present invention, and FIG. 2 is a partially enlarged vertical sectional view. DESCRIPTION OF SYMBOLS 1...Base material, 3...Blade part, 3'...Blade edge, 5...Nickel film, 10...Enamel layer, 11...Design.

Claims (1)

[Claims] 1 Stainless steel plate material used for cutlery is cut out and trimmed to the desired external shape, its surface is roughened, and then a nickel film layer is formed on the outer surface as an oxidation-inhibiting layer for pretreatment, and the expansion rate is then adjusted. A thin film of high-temperature-stable glaze is applied directly to the product, and the glaze is fired at the required temperature to form an enamel layer. After that, it is quenched with or without painting, and then tempered. A method for manufacturing stainless steel cutlery with enameling process.