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Controlled cool down for joining sintered parts of different sizes and shapes

IP.com Disclosure Number: IPCOM000244330D
Publication Date: 2015-Dec-02
Document File: 2 page(s) / 23K

Publishing Venue

The IP.com Prior Art Database

Related People

Andrew Thompson: AUTHOR [+2]

Abstract

Introduction of a controlled cool down rate to the sinter fuse method for joining sintered cemented carbide or cermet parts, to a rate of 0.5 – 1.5°C from the hold temperature of about 1340 to 1360°C to about 900°C, has been shown to improve the quality of the interface, therefore increasing the service lifetime of the part and the production yield.

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Controlled cool down for joining sintered parts of different sizes and shapes

Yi Cui

Andrew Thompson

Abstract

Introduction of a controlled cool down rate to the sinter fuse method for joining sintered cemented carbide or cermet parts, to a rate of 0.5 – 1.5°C from the hold temperature of about 1340 to 1360°C to about 900°C, has been shown to improve the quality of the interface, therefore increasing the service lifetime of the part and the production yield.

Introduction

Patent applications WO2014141172A1, WO2014141173A1 and WO2014141174A1 describe a method of joining a plurality of sintered cemented carbide or cermet parts to form a unitary body whereby the two parts are subjected to a vacuum or gas atmosphere, without the application of external pressure to a temperature sufficient to fuse the at least two sintered parts together at the bonding interface to form the unitary body. Introduction of a controlled cool down rate can improve the quality of the bonding interface.

Description

As described in patent applications WO2014141172A1,WO2014141173A1 and WO2014141174A1 the method of joining the plurality of sintered cemented carbide or cermet parts is to heat the at least two sintered parts to a temperature of about 1340°C to about 1360°C for a time period of about 10 to about 30 minutes.  

It has been found that by introducing a controlled cool down rate of from 0.5°C to 1.5°C per minute to control the cooling from the hold temperature (of between about 1340°C to about 1360°C) until a temperature of about 900°C is reached will improve the quality of the join. The temperature is controlled by gently decreasing the furnace power, no gas is employed. The reduced cool down gives the cobalt more time to diffuse inside the blank thereby reducing the creation of voids and gaps that may have otherwise formed. The improve...