Tin Bronze With Bismuth & Lead 1

[mrfailure]

I am trying to identify the source for a tin bronze bearing alloy containing 1.5% Pb and 2.2% Bi. It is a dry bearing and these elements add lubricity. I can understand the presence of either lead or bismuth but not the presence of both together. I checked the UNS copper alloys (i.e. CDA) but they do not show both elements used in such significant quantities in the same alloy.

Any suggestions?

 

[metengr]

This may be a customized cast tin bronze bearing alloy. We have some aged power generation equipment and over the years I have seen horizintal split sleeve bearings and cast bearing housings that do not meet specification. No surprises.

 

[skeener]

Hi mrfailure,

Have you found the alloy in question? The reason I ask is that I too am in search of said alloy. Is your application an "H" bearing by chance?

Thanks, Skeener

 

[Metalhead97]

mrfailure,

The only reason I would think to use bismuth in a leaded Sn-bronze is to substitute for lead in order to reduce the lead content since bismuth also reduces the stickiness of the alloy.

MH

http://www.linkedin.com/pub/luke-autry/1b/510/566

 

[dshore]

A producer of this alloy is

http://www.ingot.ca

What you have listed is a custom alloy. I suspect that the lead content is within a certain range due to the hazards associated with lead, and the bismuth is then added as a substitute for lead.

Thanks

 

[mrfailure]

Any idea why such a custom alloy would still have any lead instead of replacing it entirely with bismuth?

 

[dshore]

A couple of reasons...

1. The price of bismuth is about $ 11.00 a pound and the price of lead is about $ 1.00 a pound, so it pays to use as much lead as permitted and as little bismuth as needed.

2. While bismuth is very similar to lead, lead has higher lubricity and is distributed more evenly in a copper matrix than bismuth.

ds

 

[dshore]

Another possible supplier of this alloy is :

http://www.cmxmetals.com/

 

[skeener]

dshore,

Thank you for the information.

Thanks, Skeener