Assembly fitting (tungsten carbide into a steel)

[rpacheco85]

Hi everyone,

i'm a Portuguese student and i work as a engineer, i want to know if someono can help with some information (stresses, assembly fits equation) related to assembly fitting. assembly fitting refers to a carbide that is mounted into a steel case (like a die for extruding). If someone could help me.

Thanks

Rui Pacheco

 

[TVP]

There was a previous discussion on this topic that has some good links to references, websites, etc.

http://www.eng-tips.com/viewthread.cfm?qid=252874

 

[tomwalz]

I can probably help you.

The more information you could give me the better I could help you.

I assume you are talking about brazing carbide into a die. Typically the steel grows so much more than the carbide that it leaves a gap between the carbide and the steel so big that you don't get wetting on both sides. I often recommend pre-positioning the braze alloy and flux below the carbide part then heating until the carbide part settles down. This will leave a gap between the carbide and the steel. You can then go back and fill this gap from above although this is generally an appearance issue and not very often a functional issue.

I like a 49% silver braze alloy with manganese. I like to see at least 0.005” all the way around the carbide including underneath. This increases stress relief and provides good impact resistance.

I prefer dumping little braze alloy bits down the hole and letting the braze alloy flow and wick. I do not like playing with tri-metal foil for a variety reasons but mostly cost and effectiveness.

Sincerely,
Tom Walz


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.