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Study of water based cemented carbide (WC-Co) manufacture

IP.com Disclosure Number: IPCOM000240691D
Publication Date: 2015-Feb-18
Document File: 7 page(s) / 1M

Publishing Venue

The IP.com Prior Art Database

Related People

Weeranoot Humpage: INVENTOR

Abstract

This study covered the whole process of manufacturing of cemented carbide (i.e. WC-Co) and cermet in any grain with deionised water as a milling liquid media. The purpose of the study was to understand the process and the behaviour of the material manufactured by water based technology. The milling methods used in this study are ball mills and an alternative high energy attritor mill (i.e. Perl Mill). The drying of the slurry in this study was done in both conventional air oven and spray drying technology. Metallurgical, chemical and physical properties affected by the change of the milling liquid media were identified. The use of alkaline amine based additives is effective at inhibiting oxidation of the grains, resulting in a water based cemented carbide material of similar properties as organic solvent based material.

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Study of water based cemented carbide (WC-Co) manufacture

Weeranoot Humpage Peter Fuller

SANDVIK HYPERION Torrington Avenue COVENTRY CV4 9AB,

United Kingdom

Abstract

This study covered the whole process of manufacturing of cemented carbide (i.e. WC- Co) and cermet in any grain with deionised water as a milling liquid media. The purpose of the study was to understand the process and the behaviour of the material manufactured by water based technology. The milling methods used in this study are ball mills and an alternative high energy attritor mill (i.e. Perl Mill). The drying of the slurry in this study was done in both conventional air oven and spray drying technology. Metallurgical, chemical and physical properties affected by the change of the milling liquid media were identified. The use of alkaline amine based additives is effective at inhibiting oxidation of the grains, resulting in a water based cemented carbide material of similar properties as organic solvent based material.

Introduction

Change of the milling liquid media from organics solvent, i.e. acetone, alcohols, hexane etc. to deionised water has been driven by environmental concerns and the Health & Safety point of view. This study covered the entire manufacturing route from milling to granulation of the water based cemented carbide at any grain sizes.

Experiment

Milling

The chemical composition of this study remained consistent throughout the study. Cobalt was used as a metallic binder with additional inhibitors such as Ta, Ti, V, Cr added to control the microstructure. The Solid/Liquid ratio is approximately 85/15*. An amount of 0.1 up to 8.0 weight per cent of long chain water-soluble polyglycol and poly ether glycol at different molecular weights were added into the total solid weight. These long chain organic lubrications were added at the beginning of mill. This is to ensure that the grains are coated in long chain polymers during the milling process and improves the bulk density, compaction and powder flow properties.

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Composition used: Fine grain size tungsten carbide with cobalt binder matrix of approximately 10 weight per cent* and grain growth inhibitors. The milling liquid is deionised water. The additional chemicals are listed as following:


 Approximately* 0.1- 5.0% water based amine a product of high alkaline (pH8-
14.0) was used as anti-corrosion agent. This product coats the grains to reduce the oxidation of the grains (attritor milling is normally used as milling times are shorter, therefore the reducing the oxidation risk, however this addition resolves the oxidation problem associated with the longer milling times when using a ball milling process).


 Approximately* 0.01- 1.0% antifoaming agent (fatty poly glycol) added with (pH 10%).


 Approximately* 0.01- 1.0% stabilizing agents added to slow the surface shear rate and improve viscosity of the slurry.


 pH maintained between 8-14 throughout.


 Viscosity between 700- 170...