# US 2021/0276092 A1 · Method of heat treating a cemented carbide material

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- Number: US 2021/0276092 A1
- Document ID: US20210276092A1
- Status: Published application
- Kind: A1
- Application number: 17/260,706
- Filed: 2019-08-15
- Published: 2021-09-09
- Earliest claimed: 2018-08-16
- Assignees: Element Six Limited
- Applicants: Element Six GmbH
- Inventors: IGOR YURIEVICH KONYASHIN; HAUKE HINNERS; BERND HEINRICH RIES
- Web page: https://patentgrep.com/patent/US20210276092A1

## CPC

- B22F 5/00: Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
- C23C 4/10: Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
- B22F 3/24: After-treatment of workpieces or articles {(B22F3/1146 takes precedence)}
- B22F 7/08: with one or more parts not made from powder {(B22F7/062 takes precedence)}
- B23K 9/04: Welding for other purposes than joining, e.g. built-up welding
- B23K 9/042: {Built-up welding on planar surfaces}
- C22C 1/051: Making hard metals based on borides, carbides, nitrides, oxides or silicides; Preparation of the powder mixture used as the starting material therefor
- C22C 29/08: based on tungsten carbide
- C23C 4/067: containing free particles of non-metal elements, e.g. carbon, silicon, boron, phosphorus or arsenic
- C23C 4/12: characterised by the method of spraying
- C23C 4/134: Plasma spraying
- C23C 4/18: After-treatment
- C23C 26/02: applying molten material to the substrate
- C23C 30/00: Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence)
- B22F 2003/248: {Thermal after-treatment}
- B22F 2005/001: {Cutting tools, earth boring or grinding tool other than table ware}
- B22F 2302/10: Carbide
- B22F 2998/10: Processes characterised by the sequence of their steps
- B23K 2101/20: Tools
- C21D 2251/04: Welded or brazed overlays
- E21C 35/1835: {Chemical composition or specific material}
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- 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)
- E21C: MINING OR QUARRYING

## Abstract

This disclosure relates to a method of producing a tool comprising a substrate and a hard-face coating metallurgically bonded to the substrate. The method comprises the steps of: providing a steel substrate; providing a composition of fully sintered granulate grains; and then applying the fully sintered granulate grains onto the substrate. The resultant cemented carbide material on the steel substrate comprises a specific composition and includes a metastable phase having a nanohardness of at least 12 GPa and a Palmqvist fracture toughness of below 7 MPa m½. The method includes heat-treating the hard-face coating to at least partially decompose the metastable phase, to increase the Palmqvist fracture toughness.

## Claims

### Claim 1

A method of producing a tool comprising a substrate and a hard-face coating metallurgically bonded to the substrate, the method comprising the steps of:
providing a steel substrate;
providing a composition of fully sintered granulate grains;
applying the fully sintered granulate grains onto the substrate;
the resultant cemented carbide material on the steel substrate comprising at least 0.1 wt. % Si, at least 5 wt. % Cr, less than 5 wt. % Mn, less than 10 wt. % Mo, at least 30 wt. % W, and the balance of the cemented carbide material comprising C and an iron group metal, M, M being selected from any of Co, Ni or an alloy thereof, the cemented carbide material further comprising inclusions of a metastable phase, the metastable phase comprising M, Cr, Si, W, and C, the metastable phase having a nanohardness of at least 12 GPa and a Palmqvist fracture toughness of below 7 MPa m1/2;
the method further comprising:
subsequently heat treating the cemented carbide material and substrate at a temperature of at least 700° C. to at least partial decomposition of the metastable phase, thereby producing a tool with a substrate and a hard-face coating metallurgically bonded to the substrate.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising performing a second heat treatment at temperature in the range of 300° C. to 700° C. for between 10 and 360 minutes.

### Claim 3 (depends on 2)

The method according to claim 2, further comprising performing at least one further second heat treatment.

### Claim 4 (depends on 1)

The method according to claim 1, further comprising quenching the heat treated cemented carbide material in any of water, oil, air, nitrogen, helium or a polymeric solution.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising cooling the cemented carbide material using at least one predetermined cooling rate.

### Claim 6 (depends on 1)

The method according to claim 1, further comprising forming a carbide precipitate in a binder phase.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the carbide precipitate comprises any of M23C6, M7C3, M3C2, M12C, M6C, M4C or M3C2.

### Claim 8 (depends on 6)

The method according to claim 6, wherein the carbide precipitate has an average particle size selected from any of no more than 200 nm, and no more than 100 nm.

### Claim 9 (depends on 1)

The method according to claim 1, further comprising forming any of Fe3W2 particles, FeSi particles, Cr5Si3 particles, and SiC particles during the heat treatment.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the hard-face coating has a Vickers hardness selected from any of at least 800 HV10, at least 900 HV10 and at least 1000 HV10.

### Claim 11 (depends on 1)

The method according to claim 1, further comprising forming nano-precipitates of mixed (Cr, M)23C6.

### Claim 12 (depends on 1)

The method according to claim 1, further comprising forming nano-precipitates of at least one phase of the W—Fe—C system.

### Claim 13 (depends on 1)

The method according to claim 1, further comprising forming a nano-structured Fe-based binder matrix with a ferritic, austenitic or martensitic structure having mean grain size selected from any of below 50 nm, below 30 nm and below 20 nm.

### Claim 14 (depends on 1)

The method according to claim 1, wherein the step of applying the fully sintered granulate grains onto the steel substrate comprises a high temperature plasma spraying operation.

### Claim 15 (depends on 1)

The method according to claim 1, wherein the metastable phase comprises 50 wt. % to 70 wt. % M, 5 wt. % to 15 wt. % Cr, less than 10 wt. % Si, 10 to 40 wt. % W and 1 to 5 wt. % C.

### Claim 16 (depends on 1)

The method according to claim 1, wherein the metastable phase comprises 55 wt. % to 65 wt. % M, 5 wt. % to 15 wt. % Cr, less than 7 wt. % Si, 15 wt. % to 30 wt. % W and 2 wt. % to 4 wt. % C.

### Claim 17 (depends on 1)

The method according to claim 1, wherein the metastable phase comprises 50 wt. % to 70 wt. % M, 5 wt. % to 15 wt. % Cr, less than 10 wt. % Si, 15 wt. % to 30 wt. % W, 2 wt. % to 4 wt. % C, less than 5 wt. % Mn, and less than 10 wt. % Mo.

### Claim 18 (depends on 1)

The method according to claim 1, wherein the metastable phase has a cubic lattice structure.

### Claim 19 (depends on 1)

The method according to claim 1, wherein the metastable phase has a hexagonal lattice structure.

### Claim 20 (depends on 1)

The method according to claim 1, wherein the metastable phase has a tetragonal lattice structure.

### Claim 21

(canceled)

### Claim 22

(canceled)