I'm having a replacement brake caliper piston machined from 304 s/s bar stock for my little '76 CB250, as the stock one is chromed carbon steel and has been eaten by years of brake fluid. My question is, will the 304 have enough corrosion resistance to handle brake fluid for years to come? I got a 1.5inch diameter by 7 inch long chunk for free, and need to make sure it can handle this before I get it machined. I would have preferred 316, but 304 is what I got.
Am I good?
I'm no metallurgist, or rocket scientist, but if chromed steel was good...
I think the stainless will be too.
Brake fluid won't attack 304. It also won't attack the chrome plated steel in your original piston and what attacked it was water in the brake fluid. The 304 should hold up well, even with some water contamination but may suffer some slight corrosion with time and water contamination...we all need to occasionally flush our brake and hydraulic clutch systems and replace the old fluid with new. I'm as guilty of anyone of neglecting brake fluid changes.
Bob
Thank you both. I'm gonna go ahead and have it machined then. I'll be changing brake fluid alot more often than the PO did, I can assure you. [thumbsup]
chrome's the key. sturdy stuff.
304 stainless. 3 parts chrome, 0 parts moly, 4 parts nickel... plus the steel of course.
Quote from: corey on November 04, 2011, 01:23:35 PM
chrome's the key. sturdy stuff.
304 stainless. 3 parts chrome, 0 parts moly, 4 parts nickel... plus the steel of course.
...and nickel is pretty corrosion resistant too.
maybe that's why they call it stainless? ;D
[cheeky]
Now I'll be digging into metallurgy, to keep from anymore embarrassing newb posts. ;D
Quote from: The Zombie Pip on November 04, 2011, 01:56:44 PM
Now I'll be digging into metallurgy, to keep from anymore embarrassing newb posts. ;D
The DMF: Inspiring Educational Excellence
304 is a beyotch to machine, let us know what the shop says.
Quote from: Speeddog on November 04, 2011, 07:58:23 PM
304 is a beyotch to machine, let us know what the shop says.
Speeddog has a good point. Here's a link to one of many places where you can buy 303 SS, very similar corrosion resistant properties to 304, but I think it has better machining properties:
http://www.speedymetals.com (http://www.speedymetals.com)
Not free but relatively cheap for the small amount you need.
Quote from: Speeddog on November 04, 2011, 07:58:23 PM
304 is a beyotch to machine, let us know what the shop says.
at least it's not inconel
Quote from: teddy037.3 on November 05, 2011, 09:59:15 AM
at least it's not inconel
There you go Pip...
send it to T-dogg... ;D
Quote from: ducpainter on November 05, 2011, 10:12:33 AM
There you go Pip...
send it to T-dogg... ;D
pimping me out now, are we? [cheeky]
Quote from: teddy037.3 on November 05, 2011, 10:42:07 AM
pimping me out now, are we? [cheeky]
Not really...
you just didn't seem scared of a little stainless. ;)
Quote from: ducpainter on November 05, 2011, 10:45:14 AM
Not really...
you just didn't seem scared of a little stainless. ;)
well, yeah... but I'd just use my seniority to tell one of the lathe guys to make it for me [evil]
Quote from: teddy037.3 on November 05, 2011, 10:53:18 AM
well, yeah... but I'd just use my seniority to tell one of the lathe guys to make it for me [evil]
That's fine...
get it handled. :P
Quote from: ducpainter on November 05, 2011, 10:54:39 AM
That's fine...
get it handled. :P
Yeah, what he said! I can mail this off to ya, Teddy. [thumbsup] ;D
Quote from: ducpainter on November 05, 2011, 10:54:39 AM
That's fine...
get it handled. :P
Quote from: The Zombie Pip on November 06, 2011, 07:24:02 PM
Yeah, what he said! I can mail this off to ya, Teddy. [thumbsup] ;D
[laugh] y'all are too much sometimes
Quote from: The Zombie Pip on November 04, 2011, 01:56:44 PM
[cheeky]
Now I'll be digging into metallurgy, to keep from anymore embarrassing newb posts. ;D
one of my clients at work is a specialty stainless manufacturer, so i've been learning a lot lately.
It's pretty interesting stuff.
Quote from: corey on November 09, 2011, 01:42:25 PM
one of my clients at work is a specialty stainless manufacturer, so i've been learning a lot lately.
It's pretty interesting stuff.
Does he wanna do a little pro bono brake piston? ;D [thumbsup] [laugh]
since I've got my machinery handbook right... here... it sayeth:
304 has 18-20% Cr, 8-10.5% Ni, .08% C, 2% Mn, .75% Si, .045% P, .030% S .1% N
316 has 16-18% Cr, 10-14% Ni, same C, Mn, P, S, N, and adds 2-3% Mo
304: low-carbon modification of type 302 for restriction of carbide precipitation during welding.
316: higher corrosion resistance than 302 and 304; high creep strength. *whatever that means
High creep strength means that the material will not deform permanently (as easily) at high temperatures.
IE, some materials suffer drastically reduced yield strength at elevated temperatures.
Quote from: Speeddog on November 10, 2011, 10:43:00 AM
High creep strength means that the material will not deform permanently (as easily) at high temperatures.
IE, some materials suffer drastically reduced yield strength at elevated temperatures.
cool beans
Quote from: ducpainter on November 04, 2011, 01:54:38 PM
...and nickel is pretty corrosion resistant too.
maybe that's why they call it stainless? ;D
only in the US, the EU considers that claim to be false advertising so they have to call it something else, usually INOX from the french "inoxydable"..
Quote from: ducatiz on November 10, 2011, 12:01:17 PM
only in the US, the EU considers that claim to be false advertising so they have to call it something else, usually INOX from the french "inoxydable"..
...and certain chemicals are known to cause cancer only in California.
Stainless is close enough for me counselor. :-*
Quote from: ducatiz on November 10, 2011, 12:01:17 PM
only in the US, the EU considers that claim to be false advertising so they have to call it something else, usually INOX from the french "inoxydable"..
The legal term found on technical specifications here in the USA is "CRES" (Corrosion RESistant).
Quote from: Langanobob on November 11, 2011, 12:57:26 AM
The legal term found on technical specifications here in the USA is "CRES" (Corrosion RESistant).
???
pretty sure CRES =/= all stainless
The point was that there is stainless and then there is "stainless."
304 has a very high chromium content which is what provides the corrosion resistance, as does nickel to a lesser degree. It's a very common alloy and it's pretty cheap to get and fair for machining.
You can predict the onset of corrosion by how much chromium it has, but it's a tradeoff with machineability.
Quote from: teddy037.3 on November 11, 2011, 06:09:05 AM
???
pretty sure CRES =/= all stainless
Not sure what =/= signifies :) but I didn't mean that CRES applies only to 304 or a specific grade of "stainless steel", it applies to all. I guess my point was that "stainless" steel is not really stainless, only corrosion resistant. Depending on the environment it finds itself in it will nearly all corrode to some extent.
Quote from: Langanobob on November 11, 2011, 09:42:52 AM
Not sure what =/= signifies :) but I didn't mean that CRES applies only to 304 or a specific grade of "stainless steel", it applies to all. I guess my point was that "stainless" steel is not really stainless, only corrosion resistant. Depending on the environment it finds itself in it will nearly all corrode to some extent.
'does not equal' :)
we were taught that CRES only applies to certain grades of stainless steels... like 302, 303 are not CRES. 304, 316 are CRES. 400 series stainless aren't CRES, either.
Quote from: teddy037.3 on November 11, 2011, 11:06:00 AM
'does not equal' :)
we were taught that CRES only applies to certain grades of stainless steels... like 302, 303 are not CRES. 304, 316 are CRES. 400 series stainless aren't CRES, either.
Along with 347...
It's also magnetic.
Never heard of 347... What is it used for?
sheet steel, springs, tools
Quote from: The Zombie Pip on November 11, 2011, 04:13:47 PM
Never heard of 347... What is it used for?
When I worked in the fab shop we built a camera base for the Smithsonian.
It was mostly mild steel, but it had a center hub of 347 that had bearings and pivots for an aperture system.
I'm a painter and have no knowledge of the metallurgy or the reasoning behind the choice.
I'm just recalling experience.
Quote from: teddy037.3 on November 11, 2011, 11:06:00 AM
'does not equal' :)
we were taught that CRES only applies to certain grades of stainless steels... like 302, 303 are not CRES. 304, 316 are CRES. 400 series stainless aren't CRES, either.
OK, Doh...I got the =/= (single equal sign with a slash through it). For some reason I didn't see it that way when I first saw it, looked like some kind of ASCII Airplane.
In spite of my own vast personal storehouse of important knowledge (ha) I broke down and Googled CRES and found all kinds of conflicting information from many questionable sources. But it's been a long day and I'm going to let this discussion go. [drink]
But Stainless Steel, regardless of what it's called, is a fascinating subject.
Quote from: Langanobob on November 11, 2011, 06:28:27 PM
But Stainless Steel, regardless of what it's called, is a fascinating subject.
I wish our metallurgy class had more useful information. but then, I guess that's what the handbook is for [beer]
Quote from: Speeddog on November 04, 2011, 07:58:23 PM
304 is a beyotch to machine, let us know what the shop says.
Cake 8)
Quote from: teddy037.3 on November 05, 2011, 09:59:15 AM
at least it's not inconel
Also cake 8)
carry on
;D
Quote from: Monsterlover on November 14, 2011, 06:01:32 AM
Cake 8)
Also cake 8)
carry on
;D
Pip...send it to Kev.
It won't even cost a lot since it's so easy.;D
Just send the drawing
I have shit loads of 303, 304, 316, duplex, and inconel bar ends here.
I don't have a drawing. Can I send you the old piston? ;D
Quote from: The Zombie Chihuahua Pip on November 04, 2011, 12:08:32 PM
I'm having a replacement brake caliper piston machined from 304 s/s bar stock for my little '76 CB250, as the stock one is chromed carbon steel and has been eaten by years of brake fluid. My question is, will the 304 have enough corrosion resistance to handle brake fluid for years to come? I got a 1.5inch diameter by 7 inch long chunk for free, and need to make sure it can handle this before I get it machined. I would have preferred 316, but 304 is what I got.
Am I good?
Kind of late to be asking, but how is the bore in the caliper?
Quote from: Langanobob on November 14, 2011, 07:49:36 PM
Kind of late to be asking, but how is the bore in the caliper?
Bore is good after a little elbow grease. Strangely no rust in there...
Quote from: Monsterlover on November 15, 2011, 02:23:00 AM
Yes
Wait.... seriously???
Quote from: The Zombie Chihuahua Pip on November 15, 2011, 03:40:43 PM
Bore is good after a little elbow grease. Strangely no rust in there...
Wait.... seriously???
Quit asking anything other than the address. ??? ;D