It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out of
SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??

--
~d

_____________________________________________
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

David wrote:
It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out
of SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??


It's probably made of the same stainless that my rusty stainless
steel rustproof shower shelf is made of.

"David" wrote in message
news:HQefe.1271228$8l.910753@pd7tw1no...
It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out of
SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??

--
~d

I have no scientific explanation for it, but it's perfectly normal. I'd
venture a guess that the stainless, having been heated above a red heat for
lengthy periods of time, is oxidized such that the protective value of the
stainless alloys is lost. What we need is a chemist or metallurgist to
explain the reaction for us.

Harold

"Ignoramus11139" wrote in message
...
he probably had chromed steel, not stainless. I have a stainless grill
and there is not a single trace of rust.

i

On Sat, 7 May 2005 20:42:51 -0700, Harold and Susan Vordos
wrote:

"David" wrote in message
news:HQefe.1271228$8l.910753@pd7tw1no...
It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out
of
SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??


I have no scientific explanation for it, but it's perfectly normal. I'd
venture a guess that the stainless, having been heated above a red heat
for
lengthy periods of time, is oxidized such that the protective value of
the
stainless alloys is lost. What we need is a chemist or metallurgist to
explain the reaction for us.

Harold




--

There are several different grades of stainless. Use a magnet on it. If the
magnet sticks then it will probably rust.

From: http://bbq.about.com/od/stainlessste...a042305a_2.htm
"However there is something called 430 stainless steel. 430 stainless steel,
while technically stainless steel, will stain and rust. Yes, stainless steel
can rust. This low quality stainless steel costs a lot less than 304
stainless steel so it gets used on lower quality grills either in part or
completely. 430 stainless steel will need a lot more attention and care if
it is going to maintain its appearance. 430 stainless steel, unlike 304 is
magnetic, meaning you can stick a magnet to it so take a magnet and touch it
to every part of your grill to see if you have 430 stainless steel. If you
do you are going to need to keep these parts very clean and very dry. While
this metal is basically uncoated steel that is very prone to corrosion you
can keep it looking relatively good for several years if you take good care
of it."

Lane

"Ignoramus11139" wrote in message
...
he probably had chromed steel, not stainless. I have a stainless grill
and there is not a single trace of rust.

The amount of moisture to which you grill is exposed plays a big role. I
had a stainless burner burn out completely while living in Utah, where it's
not known for high humidity. Takes a few years, but it happens. Likely a
response to products of combustion------acid rain? g

I agree, it's possible the component in question could be plated, however.

Not all stainless alloys lend themselves to being heated repeatedly. In
fact, hardly any of them do. If you get them hot enough long enough, they
all break down if exposed to oxygen, which they are.

Harold

"Harold and Susan Vordos" wrote in message
...

"Ignoramus11139" wrote in message
...
he probably had chromed steel, not stainless. I have a stainless grill
and there is not a single trace of rust.

The amount of moisture to which you grill is exposed plays a big role. I
had a stainless burner burn out completely while living in Utah, where
it's
not known for high humidity. Takes a few years, but it happens. Likely
a
response to products of combustion------acid rain? g

I agree, it's possible the component in question could be plated, however.

Not all stainless alloys lend themselves to being heated repeatedly. In
fact, hardly any of them do. If you get them hot enough long enough,
they
all break down if exposed to oxygen, which they are.

Harold




Found this on the sci.engr.metallurgy NG via a Google search.
------------------
"Chrome migration occurs when you overheat stainless steel or locally heat
it at high temperatures for extended periods of time. Again, if the
chrome in the surface layer falls below 12% you will see corrosion
occuring with time."
------------------
Although he didn't say what temperature is "high temperatures", he war
responding to rust at the HAZ location of a weld.
Lane

Harold and Susan Vordos wrote:

"David" wrote in message
news:HQefe.1271228$8l.910753@pd7tw1no...

It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out of
SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??

--
~d


I have no scientific explanation for it, but it's perfectly normal. I'd
venture a guess that the stainless, having been heated above a red heat for
lengthy periods of time, is oxidized such that the protective value of the
stainless alloys is lost. What we need is a chemist or metallurgist to
explain the reaction for us.

Harold


Why -

We all know stainless rusts. Some like 316 doesn't because of the special alloy.
Some are rust resistant, not rust proof.

Even cooking pan stainless has problems with some acids - Tomato for example.

Some are lab grade safe, some are air safe, some are water safe, some are salt water safe.

I have SS rusting in the shop, several kinds, and two kinds that are not.

Consider the Barbie - Very hot - Chemical reactions are elevated under heat.

Consider the hood of the Barbie traps moisture that gets in when it rains. Chemistry
starts.

Martin

--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

"lionslair at consolidated dot net" "lionslair at consolidated dot net"
wrote in message ...
Harold and Susan Vordos wrote:

"David" wrote in message
news:HQefe.1271228$8l.910753@pd7tw1no...

It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out
of
SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??

--
~d


I have no scientific explanation for it, but it's perfectly normal. I'd
venture a guess that the stainless, having been heated above a red heat
for
lengthy periods of time, is oxidized such that the protective value of
the
stainless alloys is lost. What we need is a chemist or metallurgist
to
explain the reaction for us.

Harold


Why -

We all know stainless rusts. Some like 316 doesn't because of the special
alloy.
Some are rust resistant, not rust proof.

Even cooking pan stainless has problems with some acids - Tomato for
example.

Some are lab grade safe, some are air safe, some are water safe, some are
salt water safe.

I have SS rusting in the shop, several kinds, and two kinds that are not.

Consider the Barbie - Very hot - Chemical reactions are elevated under
heat.

Consider the hood of the Barbie traps moisture that gets in when it rains.
Chemistry
starts.

Martin

The harsh reality is that all 300 series stainless has the potential to
rusts to some degree unless it has been passivated. One of the certified
MIL processes is to soak the material in a heated solution of nitric acid,
distilled water and potassium (di)chromate for a given period of time, which
removes the free iron. It is the free iron that rusts. The rusting,
unless accelerated by heat erosion, tends to stop on the surface. The
treatment apparently has no effect on finished diameters. High precision
parts are subjected to the treatment without making any allowances.

My experience in the aero-space and defense industry taught me that
(machined) stainless is almost always passivated to prevent surface rusting,
even when the components may not be subjected to a nasty environment.

It's not uncommon to see surface rusting on old stock stainless sheet or bar
that has been exposed to the elements. Often it's where the stock has been
in contact with ferrous materials, likely leaving an excess on the surface
from the contact.

Harold

"Lane" lane (no spam) at copperaccents dot com wrote in message
...

"Harold and Susan Vordos" wrote in message
...

"Ignoramus11139" wrote in message
...
he probably had chromed steel, not stainless. I have a stainless grill
and there is not a single trace of rust.

The amount of moisture to which you grill is exposed plays a big role.
I
had a stainless burner burn out completely while living in Utah, where
it's
not known for high humidity. Takes a few years, but it happens.
Likely
a
response to products of combustion------acid rain? g

I agree, it's possible the component in question could be plated,
however.

Not all stainless alloys lend themselves to being heated repeatedly. In
fact, hardly any of them do. If you get them hot enough long enough,
they
all break down if exposed to oxygen, which they are.

Harold




Found this on the sci.engr.metallurgy NG via a Google search.
------------------
"Chrome migration occurs when you overheat stainless steel or locally heat
it at high temperatures for extended periods of time. Again, if the
chrome in the surface layer falls below 12% you will see corrosion
occuring with time."
------------------
Although he didn't say what temperature is "high temperatures", he war
responding to rust at the HAZ location of a weld.
Lane

Pretty much any stock book worth its weight discusses the typically used
(300 series) stainless and the intergranular corrosion that occurs between
the temperatures of 800 and 1500 degrees F. It doesn't take extreme
temperatures to affect the material.

Certain alloys have been formulated to overcome the problem, but are highly
unlikely to be used in utilitarian objects. Two that come to mind are 321
and 347.

Harold

"Harold and Susan Vordos" wrote in message
...

The harsh reality is that all 300 series stainless has the potential
to rusts to some degree unless it has been passivated. One of the
certified MIL processes is to soak the material in a heated solution
of nitric acid, distilled water and potassium (di)chromate for a
given period of time, which removes the free iron.


Is this passivating process something that could easily be done in a home
shop?

- Michael

Not a good idea at all. The various levels of passivating start at 30%
nitric acid at room temp and work their way up in both percentage and
temp. Mean stuff. The solution gets contaminated quickly and disposal is
all HAZMAT.

DeepDiver wrote:
"Harold and Susan Vordos" wrote in message
...

The harsh reality is that all 300 series stainless has the potential
to rusts to some degree unless it has been passivated. One of the
certified MIL processes is to soak the material in a heated solution
of nitric acid, distilled water and potassium (di)chromate for a
given period of time, which removes the free iron.



Is this passivating process something that could easily be done in a home
shop?

- Michael

Use Google to search on Sci.engr.joining.welding. Citric acid seems to
work for passivating and is not too dangerous.

Dan

"DeepDiver" wrote in message
...
"Harold and Susan Vordos" wrote in message
...

The harsh reality is that all 300 series stainless has the potential
to rusts to some degree unless it has been passivated. One of the
certified MIL processes is to soak the material in a heated solution
of nitric acid, distilled water and potassium (di)chromate for a
given period of time, which removes the free iron.


Is this passivating process something that could easily be done in a home
shop?

- Michael

It is, but you'd likely have a hard time buying the nitric acid and the
potassium dichromate. Chemicals are quite difficult to buy now, and even
more difficult to dispose of. It was simple when I did it way back in the
mid 70's. It was by rude awakening that I realized that what I was doing
was passivating when I processed some components for an aerial surveillance
camera developing unit many years ago (I still have some of the extra
components as a memento of the job).

Needless to say, this was a defense job, which normally would have specified
a MIL spec with reference to passivation. Instead, the print had specific
requirements for the parts to be processed as I had mentioned in my previous
post. I dutifully did exactly as the print specified, giving no thought to
what I was doing. It was well after the fact that I realized that I had
passivated the parts, nothing more. My biggest regret was not having made
an exact record of the components and process. I could have used in on
many occasions.

For me, it was no chore to do the process, because at that time I was
refining gold as a hobby, so I had a fume hood and all the necessary
chemicals at hand to do the job. Handling nitric acid can be
challenging. It is quite hard on flesh.

Harold

Harold and Susan Vordos wrote:

"lionslair at consolidated dot net" "lionslair at consolidated dot net"
wrote in message ...

Harold and Susan Vordos wrote:


"David" wrote in message
news:HQefe.1271228$8l.910753@pd7tw1no...


It seems that heat and the moisture in a barbeque
turns stainless steel to junk.
Last year I paid nearly $40.00 for one of those flavour grids, made out

of

SS,
that replace the ceramic coals on a grill.
Today I found a rusty , flaking piece of what looked like mild steel.
What gives.??

--
~d


I have no scientific explanation for it, but it's perfectly normal. I'd
venture a guess that the stainless, having been heated above a red heat

for

lengthy periods of time, is oxidized such that the protective value of

the

stainless alloys is lost. What we need is a chemist or metallurgist

to

explain the reaction for us.

Harold



Why -

We all know stainless rusts. Some like 316 doesn't because of the special

alloy.

Some are rust resistant, not rust proof.

Even cooking pan stainless has problems with some acids - Tomato for

example.

Some are lab grade safe, some are air safe, some are water safe, some are

salt water safe.

I have SS rusting in the shop, several kinds, and two kinds that are not.

Consider the Barbie - Very hot - Chemical reactions are elevated under

heat.

Consider the hood of the Barbie traps moisture that gets in when it rains.

Chemistry

starts.

Martin


The harsh reality is that all 300 series stainless has the potential to
rusts to some degree unless it has been passivated. One of the certified
MIL processes is to soak the material in a heated solution of nitric acid,
distilled water and potassium (di)chromate for a given period of time, which
removes the free iron. It is the free iron that rusts. The rusting,
unless accelerated by heat erosion, tends to stop on the surface. The
treatment apparently has no effect on finished diameters. High precision
parts are subjected to the treatment without making any allowances.

My experience in the aero-space and defense industry taught me that
(machined) stainless is almost always passivated to prevent surface rusting,
even when the components may not be subjected to a nasty environment.

It's not uncommon to see surface rusting on old stock stainless sheet or bar
that has been exposed to the elements. Often it's where the stock has been
in contact with ferrous materials, likely leaving an excess on the surface
from the contact.

Harold


Which brings up the question. What does Nitric acid really do to SS.

What I have seen on some Railroad rail stock was rust nicely on the outside.
A carbide cutting tool running red hot and throwing fire and light with blue
chips tend to ?? burn the carbon off the surface area ?? and make it much less
liable to rust. Is the Nitric pasavator(sp) doing something to the carbon or what
does Fe use as a catalyst to rust ?

Martin

--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

The harsh reality is that all 300 series stainless has the
potential to
rusts to some degree unless it has been passivated. One of the
certified
MIL processes is to soak the material in a heated solution of
nitric acid,
distilled water and potassium (di)chromate for a given period of
time, which
removes the free iron. It is the free iron that rusts. The
rusting,
unless accelerated by heat erosion, tends to stop on the surface.
The
treatment apparently has no effect on finished diameters. High
precision
parts are subjected to the treatment without making any
allowances.

My experience in the aero-space and defense industry taught me
that
(machined) stainless is almost always passivated to prevent
surface rusting,
even when the components may not be subjected to a nasty
environment.

It's not uncommon to see surface rusting on old stock stainless
sheet or bar
that has been exposed to the elements. Often it's where the stock
has been
in contact with ferrous materials, likely leaving an excess on the
surface
from the contact.

Harold


Which brings up the question. What does Nitric acid really do to
SS.

What I have seen on some Railroad rail stock was rust nicely on the
outside.
A carbide cutting tool running red hot and throwing fire and light
with blue
chips tend to ?? burn the carbon off the surface area ?? and make it
much less
liable to rust. Is the Nitric pasavator(sp) doing something to the
carbon or what
does Fe use as a catalyst to rust ?

Martin


Well, from my Elements of Materials Science Book (first time I've
looked at it in years!), chromium combines with oxygen and forms an
adsorbed ionic layer to isolate the surface:

Cr + 2O2 + 2e- = (CrO4) --

Hope that clarifies things : )

"Rick" wrote in message
ink.net...


The harsh reality is that all 300 series stainless has the
potential to
rusts to some degree unless it has been passivated. One of the
certified
MIL processes is to soak the material in a heated solution of
nitric acid,
distilled water and potassium (di)chromate for a given period of
time, which
removes the free iron. It is the free iron that rusts. The
rusting,
unless accelerated by heat erosion, tends to stop on the
surface.
The
treatment apparently has no effect on finished diameters. High
precision
parts are subjected to the treatment without making any
allowances.

My experience in the aero-space and defense industry taught me
that
(machined) stainless is almost always passivated to prevent
surface rusting,
even when the components may not be subjected to a nasty
environment.

It's not uncommon to see surface rusting on old stock stainless
sheet or bar
that has been exposed to the elements. Often it's where the
stock
has been
in contact with ferrous materials, likely leaving an excess on
the
surface
from the contact.

Harold


Which brings up the question. What does Nitric acid really do to
SS.

What I have seen on some Railroad rail stock was rust nicely on
the
outside.
A carbide cutting tool running red hot and throwing fire and light
with blue
chips tend to ?? burn the carbon off the surface area ?? and make
it
much less
liable to rust. Is the Nitric pasavator(sp) doing something to
the
carbon or what
does Fe use as a catalyst to rust ?

Martin


Well, from my Elements of Materials Science Book (first time I've
looked at it in years!), chromium combines with oxygen and forms an
adsorbed ionic layer to isolate the surface:

Cr + 2O2 + 2e- = (CrO4) --

Hope that clarifies things : )

Quoting further from the same source:

"A chrominum-bearing steel is quite resistant to corrosion under an
oxidizing condition; however, in the absence of oxygen, the reaction

Cr = Cr++ + 2e-

is free to proceed. Hence we find that those steels which are passive
in the presence of oxygen or oxidizing acids such as HNO3 or H2SO4
become active in the presence of HCl, HF, or other oxygen-free acids.
A steel is therefore placed within a galvanic series of alloys at one
position or another depending on the oxidation level of the
electrolyte"

Harold and Susan Vordos wrote:

"Lane" lane (no spam) at copperaccents dot com wrote in message
...


"Harold and Susan Vordos" wrote in message
...


"Ignoramus11139" wrote in message
...


he probably had chromed steel, not stainless. I have a stainless grill
and there is not a single trace of rust.



The amount of moisture to which you grill is exposed plays a big role.


I


had a stainless burner burn out completely while living in Utah, where
it's
not known for high humidity. Takes a few years, but it happens.


Likely


a
response to products of combustion------acid rain? g

I agree, it's possible the component in question could be plated,


however.


Not all stainless alloys lend themselves to being heated repeatedly. In
fact, hardly any of them do. If you get them hot enough long enough,
they
all break down if exposed to oxygen, which they are.

Harold





Found this on the sci.engr.metallurgy NG via a Google search.
------------------
"Chrome migration occurs when you overheat stainless steel or locally heat
it at high temperatures for extended periods of time. Again, if the
chrome in the surface layer falls below 12% you will see corrosion
occuring with time."
------------------
Although he didn't say what temperature is "high temperatures", he war
responding to rust at the HAZ location of a weld.
Lane



Pretty much any stock book worth its weight discusses the typically used
(300 series) stainless and the intergranular corrosion that occurs between
the temperatures of 800 and 1500 degrees F. It doesn't take extreme
temperatures to affect the material.

Certain alloys have been formulated to overcome the problem, but are highly
unlikely to be used in utilitarian objects. Two that come to mind are 321
and 347.

Harold




Good call about the "green rot" of many 300 series stainless steels when
held at those middle temperatures. Although we don't often see problems
from this in our end (continuous flame roasters and cookers), it is a
potential problem. As far as discoloration mentioned by some, people
have to remember that is isn't called "stain-free" steel, it's
"stain-LESS" steel.

T321 would be the best option in a stainless but would be quite
expensive. We also often see 80-20 and 80-20CB specified for high
temperature stuff (up to about 2000F) but again, it gets pretty spendy
to get that exotic for a BBQ

Just on a side note, we have recently been doing a lot of commercial
flame roasters in T314 stainless. The gas flames directly hit the
stainless material and they seem to hold up well over time.

Koz

Rick wrote:

The harsh reality is that all 300 series stainless has the

potential to

rusts to some degree unless it has been passivated. One of the

certified

MIL processes is to soak the material in a heated solution of

nitric acid,

distilled water and potassium (di)chromate for a given period of

time, which

removes the free iron. It is the free iron that rusts. The

rusting,

unless accelerated by heat erosion, tends to stop on the surface.

The

treatment apparently has no effect on finished diameters. High

precision

parts are subjected to the treatment without making any

allowances.

My experience in the aero-space and defense industry taught me

that

(machined) stainless is almost always passivated to prevent

surface rusting,

even when the components may not be subjected to a nasty

environment.

It's not uncommon to see surface rusting on old stock stainless

sheet or bar

that has been exposed to the elements. Often it's where the stock

has been

in contact with ferrous materials, likely leaving an excess on the

surface

from the contact.

Harold



Which brings up the question. What does Nitric acid really do to

SS.

What I have seen on some Railroad rail stock was rust nicely on the

outside.

A carbide cutting tool running red hot and throwing fire and light

with blue

chips tend to ?? burn the carbon off the surface area ?? and make it

much less

liable to rust. Is the Nitric pasavator(sp) doing something to the

carbon or what

does Fe use as a catalyst to rust ?

Martin



Well, from my Elements of Materials Science Book (first time I've
looked at it in years!), chromium combines with oxygen and forms an
adsorbed ionic layer to isolate the surface:

Cr + 2O2 + 2e- = (CrO4) --

Hope that clarifies things : )




That sounds logical - floating the Chrome to the surface. The surface does
look to bright to be steel.

Any voids in the 'reflow' area tainted with rust now.

Thanks,
Martin - that also tells us a little of the alloy.

--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

"Koz" wrote in message
...
snip-----

Just on a side note, we have recently been doing a lot of commercial
flame roasters in T314 stainless. The gas flames directly hit the
stainless material and they seem to hold up well over time.

Koz


Interesting. I just checked an old Jorgensen stock book and it doesn't
show it. Is it a new alloy, or just uncommon? How closely does it compare
to 316?

I would have assumed 316L would have been a fair choice for your
application, assuming intergranular corrosion wasn't a problem.

I can't help but think that humidity plays a huge role in how heated
stainless holds up. I used some scrap bars of 303 S to support a mercury
retort that was heated to red heat when used (for good reason) and found
that aside from discoloration, the 303 bars held up perfectly. In fact,
the retort itself was made of 304 stainless and never failed. They were
used over a period of several years, although not daily. They were not
subjected to any stress, and likely had lost a considerable amount of
tensile strength due to intergranular corrosion, but it wasn't an issue in
my application. By contrast, the burner I lost in an old barbeque corroded
out totally in just a few years. The corrosion was around the small port
holes around the H shaped burner, creating very hot burning areas some
places, and a complete lack of flame in others. The barbeque, which resided
out of doors, was likely damp or wet quite often. By contrast, the retort
setup was kept perfectly dry.

Harold

Harold and Susan Vordos wrote:

"Koz" wrote in message
...
snip-----


Just on a side note, we have recently been doing a lot of commercial
flame roasters in T314 stainless. The gas flames directly hit the
stainless material and they seem to hold up well over time.

Koz




Interesting. I just checked an old Jorgensen stock book and it doesn't
show it. Is it a new alloy, or just uncommon? How closely does it compare
to 316?

I would have assumed 316L would have been a fair choice for your
application, assuming intergranular corrosion wasn't a problem.

I can't help but think that humidity plays a huge role in how heated
stainless holds up. I used some scrap bars of 303 S to support a mercury
retort that was heated to red heat when used (for good reason) and found
that aside from discoloration, the 303 bars held up perfectly. In fact,
the retort itself was made of 304 stainless and never failed. They were
used over a period of several years, although not daily. They were not
subjected to any stress, and likely had lost a considerable amount of
tensile strength due to intergranular corrosion, but it wasn't an issue in
my application. By contrast, the burner I lost in an old barbeque corroded
out totally in just a few years. The corrosion was around the small port
holes around the H shaped burner, creating very hot burning areas some
places, and a complete lack of flame in others. The barbeque, which resided
out of doors, was likely damp or wet quite often. By contrast, the retort
setup was kept perfectly dry.

Harold




T314: http://www.matweb.com/search/Specifi...?bassnum=Q314B

No time to look up more information right now referring to heat
resistance. However, it has been used for years in brazing and heat
treating furnaces including direct natural gas fired furnaces.

Koz

"Koz" wrote in message
...
snip-----

T314: http://www.matweb.com/search/Specifi...?bassnum=Q314B

No time to look up more information right now referring to heat
resistance. However, it has been used for years in brazing and heat
treating furnaces including direct natural gas fired furnaces.

Koz


That was more than enough to answer my questions. Thanks.

314 appears to be very high in both nickel and chromium as compared to 316,
which likely accounts for its heat resisting quality.

Harold