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bismuth free machining steel, any experience with it?

cyanidekid

Titanium
Joined
Jun 4, 2016
Location
Brooklyn NYC
I'v been trying to get a hold of some bismuth containing free machining steel, as an alternative to lead bearing alloys like 12L14, really just to experiment with.

It seems hard to find, and I'm wondering if anyone here has any experience with it?

three questions;

1) machining properties relative to 12L14,

2)weldability, I've seen claims its more weldable than the ("unweldable")sulfur/lead alloys,

3) where can you get it? Iv'e tried all the usual suspects, and none have even herd of it.

before it gets started, let's hold all the usual bloviating "I eat a pound of lead every morning for breakfast and it hasn't hurt me yet" and such, yes, I know leaded steel isn't laying waste humanity, if this stuff is more weldable that's enough reason to try it in my book.

thanks in advance, CY
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
I suspect in the US you would need to order a mill run (10's of tons, maybe) to get something like 12B14. I have never seen it on any vendor's stock list, although I don't deal in exotics very much.
 

cyanidekid

Titanium
Joined
Jun 4, 2016
Location
Brooklyn NYC
ISPAT Inland steel was supposedly making the stuff, but they went through a gauntlet of corporate takeover and selloff shenanigans. a mill run would obviously be necessary IF no one is currently producing it.

perhaps our European members could chime in on this?
 

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
I can not find my old Jorgensen book but they used to have 3 variations of 12L14. One had selenium, another tellurium SP? and a third which I have forgotten, maybe it was bismuth? These may have substituted for the normal sulfur.
Each bumped the SFM from 320 to 400+ if I remember right. I ran the one with selenium with the idea it would improve ductility when making wire rope fittings. Carpenter used to sell 303 Se for that purpose and it worked well for us also.
I understand the alloy that Hardinge uses for their collets has calcium as a free machining agent. Can not prove that but I heard something like that about 20 years ago.
 

alphonso

Titanium
Joined
Feb 15, 2006
Location
Republic of Texas
I can not find my old Jorgensen book but they used to have 3 variations of 12L14. One had selenium, another tellurium SP? and a third which I have forgotten, maybe it was bismuth? These may have substituted for the normal sulfur.
Each bumped the SFM from 320 to 400+ if I remember right. I ran the one with selenium with the idea it would improve ductility when making wire rope fittings. Carpenter used to sell 303 Se for that purpose and it worked well for us also.
I understand the alloy that Hardinge uses for their collets has calcium as a free machining agent. Can not prove that but I heard something like that about 20 years ago.


From the Jorgensen book:

12L14 Grade A: resulphorized, rephosphorized screw machine stock with lead added

Grade AX: added tellurium

Grade AY; added selenium (instead of tellurium?)

Grade AZ: added Bismuth (instead of tellurium?)

surface speed and machinability over 1212;

Grade A 325sfm 193%

Grades AX, AY, AZ 420sfm 250%
 

cyanidekid

Titanium
Joined
Jun 4, 2016
Location
Brooklyn NYC
alphonso, as I understand it, the bismuth is a substitute for the lead primarily and the tellurium stays in and functions similarly in both alloys forming an inter metallic with the lead or bismuth.
the bismuth has the advantage of being similar to iron in density, so it doesn't stratify by gravity.

Fred, interesting about Hardinge and the calcium, as during my search I believe I came across a bismuth calcium alloy.
 

alphonso

Titanium
Joined
Feb 15, 2006
Location
Republic of Texas
alphonso, as I understand it, the bismuth is a substitute for the lead primarily and the tellurium stays in and functions similarly in both alloys forming an inter metallic with the lead or bismuth.
the bismuth has the advantage of being similar to iron in density, so it doesn't stratify by gravity.

Fred, interesting about Hardinge and the calcium, as during my search I believe I came across a bismuth calcium alloy.


The way I understand the Jorgensen book is that tellurium, selenium or bismuth is added to 12l14 to make the AX, AY, AZ grades. Not as a replacement of lead. Column in table is labeled "Added Element".
 

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
I am pretty sure with 303Se the selenium replaces the sulfur. I assumed the same with the Grade AY but I never asked and the certs are buried very deep or thrown away, it was almost 30 years ago. Also assumed the lead did not change on percentage. ??
 

alphonso

Titanium
Joined
Feb 15, 2006
Location
Republic of Texas
Fred,

Jorgensen table shows the percentage of carbon, manganese, phosphorus and sulphur is the same in all four grades; A thru AZ.

303se essentially replaces the sulphur (.04 max) with selenium.
 

cyanidekid

Titanium
Joined
Jun 4, 2016
Location
Brooklyn NYC
The way I understand the Jorgensen book is that tellurium, selenium or bismuth is added to 12l14 to make the AX, AY, AZ grades. Not as a replacement of lead. Column in table is labeled "Added Element".

Ahh, ok I see. There are different categories of the bismuth containing free machining steels. Some where the goal is to replace the lead to create a lead free alloy, and others where it’s added in addition to lead to increase machinability further.
The Jorgensen alloy is in the latter category.

What year is that catalog? (And thanks for the posts!)
 








 
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