Method of surface hardening sintered bodies by using vibrations

Patent metadata

Field	Value
Publication number	US-10226819-B2
Application number	US-201314383573-A
Country	US
Kind code	B2
Filing date	Mar 7, 2013
Priority date	Mar 13, 2012
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

The present invention relates to a method of surface hardening a plurality of sintered bodies having a hard phase and a binder phase. The method includes the steps of placing the bodies in a container, and forming a system including the container and the bodies therein, and causing the bodies to move and collide with each other and with inside walls of the container. The container is vibrating utilizing a mechanical resonance frequency of the system.

First claim

The invention claimed is:

1. A method of surface hardening a plurality of sintered bodies comprising a hard phase and a binder phase, said method comprising the steps of:
placing the bodies in a container and forming a system including the container and the bodies therein, each of the bodies having a surface zone and a bulk zone extending below the surface zone; and
hardening the surface zone of each of the bodies by vibrating the container at a resonance frequency within 0.05 Hz of the resonance frequency of the system to cause the bodies to move and collide with each other and with inside walls of the container,
wherein the hardened surface zone has a hardness that is greater than a hardness of the bulk zone of the bodies.

2. A method according to claim 1 , wherein said hard phase is WC and said binder phase is Co and/or Ni.

3. A method according to claim 1 , wherein the container is vibrated with uniaxial vibrations.

4. A method according to claims 3 , wherein the movements of the bodies originate from the vibrations.

5. A method according to claim 1 , wherein the vibrations are acoustic vibrations.

6. A method according to claim 1 , wherein the container is vibrating with vibrations having a frequency of 20-80 Hz.

7. A method according to claim 1 , wherein the volume of one body is more than 100 mm 3 .

8. A method according to claim 1 , wherein the weight of one body is more than 0.01 kg.

9. A method according to claim 1 , wherein the bodies are sintered cemented carbide bodies for oil, gas or mining applications or drill bit inserts.

10. A method according to claim 1 , wherein the container is vibrating with vibrations having an acceleration of 30-100 G, where 1 G=9.81 m/s 2 .

11. A new method according to claim 1 , wherein the surface zone includes a first surface zone that extends from a surface of the body to 1 mm below the surface into the body,
wherein the bulk zone extends from 5 mm below the surface and into the body, and
wherein, inside the first surface zone, a hardness of the first surface zone is more than 4% higher than the hardness of the bulk zone.

12. A new method according to claim 11 , wherein the surface zone includes a second surface zone, and wherein a hardness of the second surface zone is more than 1.5% higher than the hardness of the bulk zone.

13. A new method according to claim 11 , wherein the surface zone includes a second surface zone that extends to 5 mm below the surface into the body, and
wherein, inside said second surface zone, a hardness of the second surface zone is more than 1.5% higher than the hardness of the bulk zone.

14. A method of surface hardening a plurality of sintered bodies comprising a hard phase and a binder phase, said method comprising the steps of:
placing the bodies in a container and forming a system including the container and the bodies therein, each of the bodies having a surface zone and a bulk zone extending below the surface zone; and
hardening the surface zone of each of the bodies by vibrating the container at a frequency at or close to the resonance frequency of the system to cause the bodies to move and collide with each other and with inside walls of the container;
wherein the container is vibrating with vibrations having an acceleration of 30-100 G, where 1 G=9.81 m/s 2 , and
wherein the hardened surface zone has a hardness that is greater than a hardness of the bulk zone of the bodies.

15. A method of surface hardening a plurality of sintered bodies comprising a hard phase and a binder phase, said method comprising the steps of:
placing the bodies in a container and forming a system including the container and the bodies therein, each of the bodies having a surface zone and a bulk zone extending below the surface zone;
causing the bodies to move and collide with each other and with inside walls of the container by vibrating the container at a frequency within plus or minus 0.05 Hz of the resonance frequency of the system and wherein the container is vibrating with vibrations having an acceleration of 30-100 G, where 1 G=9.81 m/s 2 ; and
hardening the surface zone of each of the bodies, the hardened surface zone having a hardness that is greater than a hardness of the bulk zone of the bodies.

Assignees

• Sandvik Intellectual Property
• Sandvik Hyperion AB

Inventors

• Carpenter Michael
• Geoghegan Sarah
• Keown Eugene
• Smith Jane

Classifications

• B23P9/00

  Treating or finishing surfaces mechanically, with or without calibrating, primarily to resist wear or impact, e.g. smoothing or roughening turbine blades or bearings (treatment covered by a single other subclass, see the relevant subclass, e.g. B24C, C21D7/00, C22F1/00); Features of such surfaces not otherwise provided for, their treatment being unspecified · CPC title

• B22F2202/01

  Use of vibrations · CPC title

• C22C29/067

  comprising a particular metallic binder · CPC title

• B24B1/04

  subjecting the grinding or polishing tools, the abrading or polishing medium or work to vibration, e.g. grinding with ultrasonic frequency (involving oscillating or vibrating containers B24B31/06; superfinishing surfaces on work, e.g. by means of abrading blocks reciprocating with high frequency, B24B35/00) · CPC title

• B22F2998/00

  Supplementary information concerning processes or compositions relating to powder metallurgy · CPC title