Tungsten carbide is high melting, 2,870 °C (5,200 °F) and can be extremely hard (>93 HRA). There are many different grades of Tungsten carbide and many different uses. Tungsten carbide is typically used
in high wear resistance situations such as saw blades, high speed cutting tools, drill bits, armour peircing ammunition and athletic equipment. In oil and gas applications it is typically used in drill bits and slips (essentially break pads) on oil tools used in hard casing wells.
Cemented carbide is expensive and is used only on the contact areas of parts. It can not be welded into place, instead it must be brazed using an alloy with a low melting point and excellent carbide wetting properties. There are several alloys to choose from, each has advanages and
disadvantages over the other. The two leading manufacturers of braze alloy are Johnson Matthey and Lucas Milhaupt / Harmon Handy.
Another important decision is the selection of flux for your joint, flux prevents oxidization and improves wetting. The two most common forms of flux are referred to as "white flux" and "black (borax) flux". Borax flux typically has superior
properties when working with carbide.
Brazing carbide is typically done at heats of over 600 °C (1,112 °F) and can be done with an industrial (oxygen) torch or oven. It is important to always braze in a well ventaleted area as fumes from the flux and braze can be toxic. The part must also be cleaned before brazing and only a thin layer of braze
should be applied, otherwise the carbide may compress into the soft braze alloy and throw off the tollerance(s) of the part. Special consideration must also be given to the affects of heat on the material. Most steels will begin to decarburize at the heat required for brazing making them softer and more maliable.
More information on Brazing can be found here: