JPH0526064U - Compound steel cutlery - Google Patents

Abstract

(57) [Abstract] [Purpose] The invention that can obtain a desired hardness by cold working without requiring the high temperature quenching is to provide a compound steel blade such as a kitchen knife and a sickle. And [Structure] High hardness and wear resistance for sustaining the sharpness required for blades are obtained by cold working of austenitic stainless steel to work harden it, and at the same time, when punching a press tool In order to prevent wear and cracks in the molded product, a CLAD steel plate in which a ferritic stainless steel 2 which is a low carbon soft steel is compounded with an austenitic stainless steel is made and a blade is molded. That is, austenitic stainless steel 1 that is work-hardened by cold working is compounded at a mixing ratio of 75% to 70%, and ferritic stainless steel 2 is compounded at 25% to 30%, and the compounded product is subjected to the cold working. To reduce the thickness to make only austenitic stainless steel 1 high hardness, and ferritic stainless steel 2 to produce composite steel while maintaining its softness, and form it into a predetermined knife such as a knife or sickle. Is.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a compound steel blade such as a kitchen knife and a sickle, and in particular, it can obtain a desired hardness by cold working without requiring high temperature quenching.

[0002]

[Prior Art]

 Conventionally, in the case of knives such as kitchen knives and sickles, high carbon steel or stainless steel has been subjected to high temperature quenching to obtain desired hardness in order to obtain sharpness and durability. That is, in the high carbon steel system, mainly carbon tool steel or alloy tool steel is used. Carbon tool steel is heated to 760 ° C to 820 ° C, alloy tool steel is heated to 760 ° C to 1050 ° C, and rapidly cooled with water or oil. High temperature quenching is performed to a hardness of HRC55-64. In addition, because of its high corrosion resistance and ease of use, stainless steel, which has become the mainstream these days, is made of martensitic stainless steel (JIS SUS420J2, etc.) and heated to around 1050 ° C to be air-cooled and hardened to HRC50-60. High temperature quenching processing is applied to the hardness of.

As shown in FIG. 8, a high carbon steel or stainless steel 11 which has been entirely quenched at a high temperature is used, only the central portion as shown in FIG. 9 or the cutting edge as shown in FIG. One side is made of high carbon steel or stainless steel 11 that has been subjected to high temperature quenching, and both sides are made of composite steel made of mild steel 12. Among them, the one using the composite steel shown in FIGS. 9 and 10 has high hardness only at the cutting edge portion and the other is soft, so that it is efficient in manufacturing and also when the user re-blades. have.

[0004]

[Problems to be solved by the device]

 However, high-temperature quenching has a drawback that quenching strain occurs in the heating-cooling process, and this strain has a direct adverse effect on sharpness, toughness, and wear resistance. Therefore, it requires a strain removal process to commercialize it as a kitchen knife, sickle, etc. However, this strain removal work requires skill and is inefficient, which is a major obstacle in making knives such as kitchen knives and sickles. ing.

Therefore, an object of the present invention is to provide a composite steel cutting tool using stainless steel which can obtain a desired hardness by cold working without requiring high temperature quenching.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention combines austenitic stainless steel, which has high work hardening property, and ferritic stainless steel, which has low work hardening property, and performs cold working to process austenitic stainless steel. Provided is a composite steel blade using hardened composite steel. The composite steel blade is formed of austenitic stainless steel whose blade tip is work hardened by polishing with a blade. The austenitic stainless steel is JIS SUS301 and the ferritic stainless steel is JIS SUS405. Provided is a composite steel blade using one or more selected from SUS410L, SUS430, and SUS436. Further, the present invention provides a composite steel cutting tool comprising the austenitic stainless steel in a proportion of 75% to 70% and the ferritic stainless steel in a proportion of 25% to 30%.

[0007]

[Action]

 According to such a compound steel cutting tool, since austenitic stainless steel is work-hardened by cold working, it is possible to obtain the hardness required for kitchen knives, sickles, etc. without performing high-temperature quenching that causes quenching strain. it can. Moreover, since ferritic stainless steel, which has low work hardenability, does not harden even by cold working, it is possible to make only the cutting edge part high hardness and the other soft, so that the user can re-blade even during manufacturing. Has the same merits as its efficiency.

[0008]

【Example】

 An embodiment of the composite steel cutting tool according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a plan view showing a kitchen knife and FIG. 2 is a plan view showing a sickle. Martensitic stainless steel, which is a quench-hardening chrome-based stainless steel, and non-quenching-hardening ferritic stainless steel, in which the microstructure is ferrite, even though it is the same chrome-based stainless steel, and ferritic chrome. It is roughly classified into three types, austenitic stainless steels in which sufficient nickel is added to develop a stable austenitic phase at room temperature. The present invention is characterized in that high hardness and wear resistance for maintaining the sharpness required for a blade are obtained by subjecting austenitic stainless steel to cold working and work hardening.

Austenitic stainless steel, such as JIS SUS301, is not hardened to a high temperature, but is plastically deformed by cold working such as rolling and forging at room temperature to cause work hardening. Generally, when an external force is applied to a metal, a slip phenomenon occurs in which atoms are displaced, and this slip is not a simple slip, but the stress for deformation increases with strain and is work-hardened. Austenitic stainless steel has few sliding types and is unlikely to cause cross-slip, and work hardening occurs with little strain.

However, when it is attempted to manufacture the austenitic stainless steel in which the entire knife such as a knife and a sickle is work-hardened, it has a high hardness, so that the punching tool is greatly worn when the die is pressed into the shape of the knife. There is a concern that this may cause cracks in molded products. In order to solve this, the present invention makes a CLA D steel plate in which austenitic stainless steel is compounded with ferritic stainless steel, which is a low carbon soft steel, such as JIS SUS405, SUS410L, S SUS430, SUS436, etc. Mold. That is, as shown in FIG. 5, 75% to 70% of austenitic stainless steel 1 and 25% to 30% of ferritic stainless steel, which are work-hardened by the cold working, are compounded, and this compounded As shown in FIGS. 6 and 7, only the austenitic stainless steel 1 has a high hardness and the ferritic stainless steel 2 retains its softness when subjected to the cold working to reduce the thickness. Composite steel can be manufactured. After that, it is formed into a predetermined knife such as a knife or sickle.

Then, in the shearing process by the press die for forming the blade edge shape, the square blade of the die hits the plate material, creates a droop, and further progresses to form a sheared surface, resulting in deformation. As the stress concentration on the cutting edge progresses and the work hardening of the material progresses, cracks form from the cutting edge and a fracture surface is created. Since most of the composite steel according to the present invention is mild steel, the cutting load in the above process can be reduced and the wear of the punching tool can be reduced. The blade cross section may be appropriately selected from the three-layer double-blade structure of FIG. 3 and the structure of FIG.

The JIS SUS301 is representative of the work hardenable austenitic stainless steel used in the present invention. The JIS SUS301 has further improved hardenability and temper resistance. Furthermore, in order to improve the corrosion resistance as well, it can be expected to change the content of the components and add other alloying elements. For example, increasing the amount of silicon and adding molybdenum.

Further, when the composite steel according to the present invention is subjected to low-temperature annealing at around 400 ° C. after cold working, hardening due to precipitation of compounds such as carbides is added, and the strength of the material is further improved. This is similar to the blade structure in which soft stainless steel and martensitic stainless steel are combined and quench hardened.

[0014]

[Effect of the device]

 As described in detail above, according to the compound steel cutting tool of the present invention, since the austenitic stainless steel is work-hardened by cold working, the hardness required for kitchen knives, sickles, etc. is high enough to cause quenching strain. It can be obtained without quenching. Since ferritic stainless steel, which has low work hardening, does not harden even by cold working, only the cutting edge can be made to have high hardness and the other can be made soft, so the user can re-blade during manufacturing. Even in the case, it has the efficient advantage as it is. In addition, manufactured knives such as knives and sickles have excellent corrosion resistance.

Further, compared with the case where the whole is hardened steel, the composite steel has better workability in press die cutting, cutting, cold forging, etc., and wear of the forming tool can be reduced. Furthermore, there is no forging of high temperature heating in harsh working environment for blade molding, quenching process or inefficient quenching distortion removing process that requires skill, etc. Highly efficient process such as press molding, cold forging, polishing, etc. It is possible to produce blades by combining them.

[Brief description of drawings]

FIG. 1 is a plan view showing a kitchen knife.

FIG. 2 is a plan view showing a sickle.

FIG. 3 is a sectional view of a composite steel knife according to the present invention.

FIG. 4 is a sectional view of a blade of a composite steel knife according to the present invention.

FIG. 5 is a sectional view of the composite steel of the present invention before cold working.

FIG. 6 is a sectional view of the composite steel after cold working according to the present invention.

FIG. 7 is a sectional view of the composite steel after cold working according to the present invention.

FIG. 8 is a sectional view of a blade of a conventional high carbon steel or stainless steel blade.

FIG. 9 is a sectional view of a blade of a conventional composite steel blade.

FIG. 10 is a sectional view of a blade of a conventional composite steel blade.

[Explanation of symbols]

 1 ... Austenitic stainless steel 2 ... Ferritic stainless steel

Claims (6)

[Scope of utility model registration request] 1. A composite steel in which austenitic stainless steel having a high work hardening property and ferritic stainless steel having a low work hardening property are jointly joined and cold working is performed to work harden the austenitic stainless steel. A composite steel blade characterized by the above. 2. A composite steel blade according to claim 1, which is made of austenitic stainless steel whose blade tip is work hardened by polishing with a blade. 3. The austenitic stainless steel is J
The composite steel blade according to claim 1, which is IS SUS301. 4. The ferritic stainless steel is JIS
SUS405, SUS410L, SUS430, SU
The composite steel cutting tool according to claim 1, 2 or 3, which is one kind or two or more kinds selected from S436. 5. The austenitic stainless steel is 7
5% to 70%, ferritic stainless steel 25% to 3
The composite steel cutting tool according to claim 1, wherein the compounding ratio is 0%. 6. The composite steel blade according to claim 1, 2, 3, 4, or 5, wherein the composite steel blade is a kitchen knife or a sickle.