# US 11,306,370 B2 · Blade material

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- Number: US 11,306,370 B2
- Document ID: US11306370B2
- Status: Granted
- Kind: B2
- Application number: 16/326,933
- Filed: 2017-09-06
- Published: 2019-07-11
- Granted: 2022-04-19
- Earliest claimed: 2016-09-16
- Assignees: Hitachi Metals, Ltd.
- Applicants: Hitachi Metals, Ltd.
- Inventors: Kazuhiro Yamamura
- Web page: https://patentgrep.com/patent/US11306370B2

## CPC

- C21D 9/18: for knives, scythes, scissors, or like hand cutting tools
- B26B 9/00: Blades for hand knives
- C21D 1/22: Martempering
- C21D 6/002: {containing Cr (C21D6/004 takes precedence)}
- C21D 6/02: Hardening by precipitation
- C21D 6/04: Hardening by cooling below 0 degrees Celsius
- C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence)
- C21D 8/0226: {Hot rolling}
- C21D 8/0236: {Cold rolling}
- C22C 38/00: Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00)
- C22C 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C22C 38/18: containing chromium
- C22C 38/24: with vanadium
- C21D 1/18: Hardening (C21D1/02 takes precedence); Quenching with or without subsequent tempering (quenching devices C21D1/62)
- C21D 9/46: for sheet metals
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- B26B: HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR (for harvesting A01D; for horticulture, for forestry A01G; for butchering or meat treatment A22; for manufactering or repairing footwear A43D; nail clippers or cutters A45D29/02; kitchen equipment A47J; {vegetable slicers, julienne cutters and similar devices and holders therefor, B26D3/28}; for surgical purposes A61B; for metal B23D; cutting by abrasive fluid jets B24C5/02; plier-like tools with cutting edges B25B7/22; pincers B25C11/02; handles for hand implements, in general B25G; guillotine-type cutters B26D; {perforating by non-mechanical means, e.g. by fluid jet, B26F1/26}; for erasing B43L19/00; for textile materials D06H)
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Provided is a blade material having high strength. The blade material contains, in % by mass, 0.5 to 0.8% of C, 1.0% or less of Si, 1.0% or less of Mn, 11 to 15% of Cr, and 0.1 to 0.8% of V, the remainder includes Fe and inevitable impurities, and has a thickness of 0.5 mm or less, wherein the structure of the blade material as observed after polishing the surface thereof has ferrites and carbides, the carbides have an average particle diameter of 0.5 μm or less, and a proportion of carbides containing V in the carbides is 50% or less in terms of a proportion in an area of a field of view.

## Claims

### Claim 1

A blade material which consists of, in mass %, 0.6 to 0.8% of C, 1.0% or less of Si, 1.0% or less of Mn, 11 to 15% of Cr, and 0.1 to 0.8% of V, the remainder comprising Fe and inevitable impurities, and in which a thickness is 0.5 mm or less,
wherein a structure thereof includes ferrites and carbides as observed after polishing a surface thereof, and an average particle diameter of the carbides is 0.5 μm or less, and
a proportion of carbides containing V in the carbides is 1.9% or more to 20% or less in terms of a proportion in an area of a field of view.

### Claim 2 (depends on 1)

The blade material according to claim 1, wherein a structure obtained by at least quenching and tempering the blade material, which is observed after polishing a surface of the blade material has a martensite structure, and a tensile strength is 2,050 MPa or more.

### Claim 3 (depends on 1)

A manufacturing process of a blade material, comprising:
at least quenching and tempering the blade material according to claim 1, and
polishing a surface of the blade material after processing the at least quenching and tempering, wherein a structure of the surface after polishing has a martensite structure, and a tensile strength is 2,050 MPa or more.