Help on Babbitt

[Loony44]

I mostly read and gain a lot of knowledge for this site. So I have a question about some Babbitt that was given to me. It came from a power generation plant-High steam turbine. It melts at about 450-475 degrees and my Redding hardness tester has it at 22BHN. I know this is a open question but does anyone have any idea what the make-up of the babbitt might be. From what I have read Babbitt used for bearings at steam turbines are high in Tin. Any help or suggestions would be greatly.

Thanks,
Loony44

[Omnivore]

It could be anywhere from 80+% lead to over 90% tin, with some antimony and sometimes copper. Here's a place that sells several alloys, and lists the contents;
http://www.rotometals.com/Babbit-Bearing-Alloys-s/2.htm

I don't know otherwise. You'd likely have to find somebody in the steam turbine business.

If you did a simple density test you'd get a lot closer to finding the lead content, methinks, since the main consituents are going to be lead and tin. That is assumnnig it's that important to you.

[454PB]

When I was working on turbine bearings, we just called it high speed babbitt. As was said, it's high in tin content and has some copper, but at dilution, the copper doesn't cause a problem.

I use it as pure tin, adding around 3% to the alloy.

[madsenshooter]

Not to say that it is Turbine, it could be any number of babbitts, but most of those tech types would get Turbine babbitt if they were working on a turbine. Turbine is 86% Sn, 7.5% Sb, and a whopping 8% Cu. A bit of this added to your alloy will make it very tough. I add about an ounce to WW and wind up with an alloy that casts at BHN 23 but isn't brittle.

[evan price]

Most likely high load babbitt, and it is most likely 88% or better tin. There are different grades of babbitt and different formulations across different manufacturers.

Common formulas are:

90% tin, 10% copper
89% tin, 7% antimony, 4% copper
80% lead, 15% antimony, 5% tin
75% lead, 10% tin
76% copper, 24% lead
67% copper, 28% tin, 5% lead


For high speed or high load applications you will have high tin. Yours melts at low temp and is silver color so not much copper; turbine duty is heavy load so I would guess yours is high-tin babbitt, typically around 89% tin, 7% antimony, 4% copper. This is good stuff to add as sweetener to other lead.

[Loony44]

Thank you everyone for assistance, I'm hopping it's high in tin an antimony, will mix up 5lbs pure lead and 1/2lb of this babbitt, water drop and see what the hardness is.

Thanks again

[madsenshooter]

If it's Turbine, as I listed above, here's what you're going to come out with: (.81[0,0,0,100])+(.09[86,7.5,8,0])=[7.74%Sn, .675%Sb, .72%Cu, 91%Pb] An alloy with those percentages of Sn & Sb should be around 10BHN air cooled, and this doesn't take into consideration the Cu. This is according to an old chart on type metals I found in an American Rifleman. I think you'll need a tad more Sb, and a tad less Sn. With that high a tin content, I don't think water dropping or heat treating is going to have much of an effect.

To satisfy my curiosity, let us know how it turns out.

[Loony44]

Going to try today, will let you and everyone know the outcome.

Thanks

[Loony44]

Mixed 10lbs of pure lead with 1lb of the babbitt, fluxed with saw dust, set temp of alloy at 700deg, heated mould (429640) solid nose, cast a few until everything looked good. I made a half dozen and let air cool an another half dozen water quenched. Using my redding hardness tester the air cooled was 6 BHN and the water quenched was 8 BHN.
Is it possible this babbitt is Pure Tin? The water dropped bullets didn't harden much. I have a couple bullets still in water, will test in a couple days and see if they hardened any more.

Thanks

[lwknight]

It takes time for antimony to harden. At least 1 week to be noticeably harder and about 6 weeks to be 90% to as hard as it will get.
Still the tin is what you want from babbit. The antimony will not be enough to make a difference. You gotta get that elsewhere.