How hard is "annealed" 304 stainless?
 

I'm going to turn some simple objects from small sections of annealed
304 stainless steel.

How soft is that compared to stainless items I'm familiar with like
kitchen utensils or stainless nuts and bolts?

If I want to use it in the kitchen when I'm done, will I need to harden
it to avoid having the surface easily marred? What's the best way to
harden it?

--
Ben Jackson

http://www.ben.com/

"Ben Jackson" wrote in message
...
I'm going to turn some simple objects from small sections of annealed
304 stainless steel.

How soft is that compared to stainless items I'm familiar with like
kitchen utensils or stainless nuts and bolts?

It's going to be somewhat softer. 304 can be hardened only by cold-work. A
stamped kitchen utensil picks up some hardness in stamping -- sometimes,
quite a lot. Cold-headed bolts are going to be harder than annealed 304.


If I want to use it in the kitchen when I'm done, will I need to harden
it to avoid having the surface easily marred? What's the best way to
harden it?

There is no thermal treatment that will harden it. What you get is what you
get. If it was a structural part you could have it shot-peened, which would
harden the skin. But I doubt if that's practical for what you're doing.

If you need a stainless that you can harden with thermal treatment, you need
one of the 400-series SS with some significant carbon (420 or above; you
need less carbon than you do for plain carbon steel, because the chromium
increases the hardening potential of the carbon that *is* in there), or a
precipitation-hardening grade. Unless you really need hardness, it isn't
worth it.

Here's a thorough list of the properties of 304:

http://www.azom.com/details.asp?ArticleID=965

Good luck with your project.

--
Ed Huntress

Ed Huntress wrote:

304 can be hardened only by cold-work.

That goes for all 300 series (austenetic) stainless steels.

On 2005-02-17, Ed Huntress wrote:
304 stainless steel.

How soft is that compared to stainless items I'm familiar with like
kitchen utensils or stainless nuts and bolts?

It's going to be somewhat softer. 304 can be hardened only by cold-work. A
stamped kitchen utensil picks up some hardness in stamping -- sometimes,
quite a lot. Cold-headed bolts are going to be harder than annealed 304.

Thanks. Having worked with copper in various hardnesses I wasn't sure
if annealed 304 was going to be almost butter soft like annealed copper
and require hardening before it could be used.

--
Ben Jackson

http://www.ben.com/

"Ben Jackson" wrote in message
...
On 2005-02-17, Ed Huntress wrote:
304 stainless steel.

How soft is that compared to stainless items I'm familiar with like
kitchen utensils or stainless nuts and bolts?

It's going to be somewhat softer. 304 can be hardened only by cold-work.
A
stamped kitchen utensil picks up some hardness in stamping -- sometimes,
quite a lot. Cold-headed bolts are going to be harder than annealed 304.

Thanks. Having worked with copper in various hardnesses I wasn't sure
if annealed 304 was going to be almost butter soft like annealed copper
and require hardening before it could be used.

It's not that bad, but it's pretty gummy. If you've machined copper, though,
you know what that's all about.

--
Ed Huntress

On Thu, 17 Feb 2005 17:47:15 -0600, Ben Jackson wrote:

On 2005-02-17, Ed Huntress wrote:
304 stainless steel.

How soft is that compared to stainless items I'm familiar with like
kitchen utensils or stainless nuts and bolts?

It's going to be somewhat softer. 304 can be hardened only by cold-work. A
stamped kitchen utensil picks up some hardness in stamping -- sometimes,
quite a lot. Cold-headed bolts are going to be harder than annealed 304.

Thanks. Having worked with copper in various hardnesses I wasn't sure
if annealed 304 was going to be almost butter soft like annealed copper
and require hardening before it could be used.
However, the real issue with 304 is not hardness, but toughness. It is
tough to machine, kinda like pure copper. It work hardens and wears
tools fast. And it also likes to stick to the cutting tool edge. So
enough tool pressure must be used to get a constant chip. If drilling
stops producing a chip the 304 will harden at the point of contact and
then dull the drill. Use plenty of cutting oil or coolant, slow enough
speeds, and enough tool pressure to get a constant chip. And don't
dwell with the cutting tool. It either must be cutting or it must be
removed from the work.
ERS

On Thu, 17 Feb 2005 15:13:12 -0600, Ben Jackson wrote:

I'm going to turn some simple objects from small sections of annealed
304 stainless steel.

How soft is that compared to stainless items I'm familiar with like
kitchen utensils or stainless nuts and bolts?

If I want to use it in the kitchen when I'm done, will I need to harden
it to avoid having the surface easily marred? What's the best way to
harden it?

Machinists Mantra
303..she's for me
304..she's a whore.


Rule #35
"That which does not kill you,
has made a huge tactical error"

Machinists Mantra
303..she's for me
304..she's a whore.

316, stringy and mean.

304 annealed ain't gonna be any fun either. It will smear off in long
stringy chips that will try to ruin the surface you just cut, it will
chip weld, and generally be a PITA.
The worst is if you are counting on something being 303. Last week, I
had eight parts ganged up on my miller. I work with 303 because even
though I pay 30-40% more for bar stock, I can run it twice as as fast.
So I am running along, happy, with a 6-flute roughing mill, the power
feed going and a coolant flood, and guess what-
The supply place (Nameless here but very well-known) must have been a
little short filling my order for precut stock..maybe went to the
dropoff shelf. Long story short, hit one of the pieces that was
*316*, and had what amounted to a train wreck/smashup. Out $56.00 for
the end mill, had to retram the table, but saved the parts.
Post-crash showed two parts out of 8 were that f*cking 316.
I discussed it with them when I calmed down. (Interstate death threats
are prosecuted, so I waited two days...) To their credit they did
freak out over it, went to the division that shipped it and
"interviewed" the guy who filled the order, offered me a credit, etc.,
called the house about 40 minutes after I sent the e-mail.

But I only THOUGHT I hated T316 before this.

On Fri, 18 Feb 2005 07:26:15 -0500, Grunty Grogan wrote:



Machinists Mantra
303..she's for me
304..she's a whore.

316, stringy and mean.

Added! Thanks!

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

Machinists Mantra
303..she's for me
304..she's a whore.

316, stringy and mean.

Added! Thanks!

6-4 Ti, Wanna die.

Inconel makes tools blunt,
But Hastelloy's a real c...

"Gene Kearns" wrote in message
...
On Fri, 18 Feb 2005 11:25:26 -0500, Grunty Grogan wrote:



But I only THOUGHT I hated T316 before this.

I worked in a machine shop with an associated foundry. If anybody ever
found out exactly how this happened they didn't tell, but a bucket or
two of ball bearings were dumped into the melt at some point such that
they didn't melt.....

Nothing like spending two days machining on a large casting and
hitting what looked liked grapes..... it isn't fun trying to run from
what was left of a 1.5 inch diameter end mill that was 8 inches long,
either....

For the next several weeks, an eruption of cussing and brisk activity
was most likely caused by hitting one of those little joys....

We hit a HSS tap once, right in the middle of a block of steel. I forget
what the grade was. We sent it back to the service center and suggested they
wrap it around their necks. g

--
Ed Huntress

On Fri, 18 Feb 2005 16:35:40 -0500, "Ed Huntress"
wrote:


We hit a HSS tap once, right in the middle of a block of steel. I forget
what the grade was. We sent it back to the service center and suggested they
wrap it around their necks. g
I had heard on someone hitting a FILE in an iron casting. Old
machinist told me about it. I thought it had happened decades before,
but the way he was animated, it could have happened that morning.
People STAY ****ed off about those things.
In retrospect, my discussion with the metal supplier was a LOT like
the phone call from the President to the Premier in "Doctor
Strangelove"!
"This is a FRIENDLY CALL! If it were not, we would not be having it".
(You'd get nuked/ You'd be getting a summons..)

"Grunty Grogan" wrote in message
...
On Fri, 18 Feb 2005 16:35:40 -0500, "Ed Huntress"
wrote:


We hit a HSS tap once, right in the middle of a block of steel. I forget
what the grade was. We sent it back to the service center and suggested
they
wrap it around their necks. g
I had heard on someone hitting a FILE in an iron casting. Old
machinist told me about it. I thought it had happened decades before,
but the way he was animated, it could have happened that morning.
People STAY ****ed off about those things.

I'll say. It was 30 years ago and I'm still ****ed. g It wasn't really as
bad as it could have been, though, because the block was being roughed with
a ratty old endmill that I would have scrapped anyway, if it were me. We did
have to show it to the customer to explain why the job was late, which is
the reason I'm still ****ed.

In retrospect, my discussion with the metal supplier was a LOT like
the phone call from the President to the Premier in "Doctor
Strangelove"!
"This is a FRIENDLY CALL! If it were not, we would not be having it".
(You'd get nuked/ You'd be getting a summons..)

Or his precious bodily fluids would be leaking out...

--
Ed Huntress

On Fri, 18 Feb 2005 20:42:10 -0500, Grunty Grogan wrote:

On Fri, 18 Feb 2005 16:35:40 -0500, "Ed Huntress"
wrote:


We hit a HSS tap once, right in the middle of a block of steel. I forget
what the grade was. We sent it back to the service center and suggested they
wrap it around their necks. g
I had heard on someone hitting a FILE in an iron casting. Old
machinist told me about it. I thought it had happened decades before,
but the way he was animated, it could have happened that morning.
People STAY ****ed off about those things.
In retrospect, my discussion with the metal supplier was a LOT like
the phone call from the President to the Premier in "Doctor
Strangelove"!
"This is a FRIENDLY CALL! If it were not, we would not be having it".
(You'd get nuked/ You'd be getting a summons..)
I worked at a place where we would get castings from a customer who
was buying the cheapest iron for the pours. We found ball bearings,
races, and taps in these castings. We refused to do anymore until they
used better mnaterial. The material improved for a while then we
started getting hard spots again. Not taps etc., but just big
amorphous spots and lines of extra hard material. The castings looked
allright but some had spots on the outside that were slightly raised
and just a little different in color. After machining these spots the
color was very different. I told my boss that these castings must have
been weld repaired because of porosity. He didn't think so because the
surface of the castings had a uniform sand cast finish. But when he
asked the customer they admitted that they were welding up the ****ty
castings and blasting them with steel shot after welding and grinding
to hide the welds.
ERS