Impacts on 304 stainless steel

Date 06-21-2007 13:44

If the choice was mine, no (assuming the -1 temperature is the minimum temp).

We've done stainless at -325F and the energy is still extremely high evn at that temperature. In my opinion, Charpy's at -1 for stainless is overkill.

Charles

By CWI555

Date 06-22-2007 00:28

I have to agree with the negative 1 statement. It doesn't qualify for refrigerated, much less cryogenic.
-320F is the boiling temperature of liquid nitrogen. Which is the typical temperature most -77k cryogenic applications test for.
At cryogenic temperatures there is some concern, delta ferrite has to be monitored and controlled more closely. Especially when
you get to -20K and below.
For your application, I am not even sure it's required by any code, much less of any use.

Regards,
Gerald

By G.S.Crisi (****)

Date 06-22-2007 12:01

Gerald,
there's some confusion regarding at which temperature cryogenics starts. Some books say one thing, other say another one.
What's your personal opinion?
Could you point me to a site speaking of cryogenics?
Thank you.
Giovanni S. Crisi

By chuck meadows (***)

Date 06-22-2007 17:34 Edited 06-22-2007 18:52

Giovanni,
Very good question, but I don't think there is an exact temperature number where "cryogenic" starts. Cryogenic is considered "low temperature" applications, -196C or -320F. But, there are also "moderate low temperature" applications that must pass the same lateral expansion tests, and that temperature is around -150F or -100C. For cryogenic applications, to determine freedom from embrittlement failure, Section VIII of the ASME Boiler and Pressure Vessel Code sets the minimum test requirements. I believe the word "cryogenic" refers to the low temperature application of -196C. If we use the words "low temperature" or "moderate low temperature", then that could incorporate temperatures in the -100C range. I, too, would like to know exactly where cryogenic is considered only that, if there is a specific temperature. Since "cryogenic" and "low temperature" applications are normally considered the same application, where does "low temperature" start? Since, for testing purposes, "moderate low temperatures" start around -100C, I would thing that "cryogenic" would incorporate temperatures lower that -100C, if there is such an exact temperature. Sorry for rambling on and on.

Chuck

By CWI555

Date 06-22-2007 19:12

Whats refigerated and whats crygenic depends on the code in question. For instance, API 620 appendix R defines a temp range of +40F to -60F inclusive for refigerated. In the same document appendix Q it classifys it as temperatures of liquid hydrocarbons, but not lower than -270F. and in the next paragraph defines it as -60 to -270.
B31.3 gets into fluid classes and specific welding requirements for the temp at hand.

I've got some documentation on the matter, I'll dig it out and fwd it to you when I have the chance.

My opinion runs in line with API. although I think it should be a little lower based on personal experience, but not by much, more like -70f and below.
On a side note, I've never seen a problem with -1F. I can't think of any metal that would have a problem at that temperature.

Regards,
Gerald

By CWI555

Date 06-22-2007 20:58

A case could be made in B31.3 that -104C and colder is considered cryo. Again it depends on the code in question.

By G.S.Crisi (****)

Date 06-21-2007 14:36

I agree with Charles.
Giovanni S. Crisi
Sao Paulo - Brazil

By thesmiths1969 (*)

Date 06-22-2007 06:14

Thank you people

By js55

Date 06-22-2007 18:37

Also,
If you do impacts on SS at those temps you may end up paying a recalibration fee on the Charpy machine. They get out of calibration when the material is so tough the hammer doesn't break it.

By CWI555

Date 06-22-2007 20:57

ASME B31.3 04
"Table 323.2.2 Requirements fo rlow temperature toughness test for metals.
Column B Desing mimimum temperature Below Min. Temp in Table A-1 or figure 323.2.2A
Type of material (4) Austenetic stainless steels
column B-4 Base metal and weld metal deposits shall be impact tested per para. 323.3. See notes (2),(3), and (6)"

note 2 summary pqr shall satisfy requirements and need not retest.
note 3 impact test not required between -29C but at or above -104c. summary if its colder than -104c stress ratio defined in 323.2.2B is exceeded it's impact tested.

There are more quotes in the pressure piping series for this, but I think you get the idea.
Impact testing is not required if it's warmer than -104C in all cases that I could find.
I have seen and personally performed impact testing on cryogenic applications and can definitively tell you that at -320F (boiling temp for liquid nitrogen) Most 304 welds will break. The ones that do not, are typically the ones that have been welded without close control of delta ferrite. It is in inaccurate statement to say that cryogenic testing of austenitic stainless steel will damage the calibration at normal cryogenic testing temperature.

If you hit one at -20 or something silly like that, I cannot speak for it, as no code I am aware of requires it for austenitic SS and therefore, I've never seen it.

Regards,
Gerald

By js55

Date 06-25-2007 13:30

Gerald,
I've never performed Charpies in SS at those high temps either. Why would you want to? But I have perfomed plenty of Charpies on Ferritics/Bainitics/Martensitics at temps determined by code or contract that would stop the hammer, even 240 ft/lb machines. Usually if it happens once or twice the labs are pretty good about it and proceed without issue, at least the labs that I've dealt with. If it keeps happening they will generally start charging recalibration fees. And justifiably.
Materials are generally just better than they used to be, especially when it comes to hitting chems per heat, and residual elements. And if you do stop the hammer how do you report your results?

By CWI555

Date 06-25-2007 16:02

SA 370 Identical with ASTM Specification A 370-02

"25.4.3.7 With the exception described as follows,
any specimen that does not separate into two pieces when
struck by a single blow shall be reported as unbroken. If
the specimen can be separated by force applied by bare
hands, the specimen may be considered as having been
separated by the blow."

The fact that it's specifically called out is a statement that it happens on a basis that is more frequent than realized.

Regards,
Gerald

By js55

Date 06-25-2007 16:27

Gerald,
I never noticed that paragraph before.
thanks

By Joseph P. Kane (****)

Date 06-25-2007 14:26

Back in the 1990s, a Mr. Steve Kane, (no relation) did some extensive Charpy work on Austenitic SS for the Relativistic Heavy Ion Collider at Brookhaven National Laboratories in Upton NY. Perhaps there is a way to get to that work through the internet.

By js55

Date 06-25-2007 16:30

Relativistic Heavy Ion Collider for sure. I did a S Kane search at the DOE site and you oughta see the fermion/boson/Higgs field stuff that pops up. Holy moley!!

By ssbn727 (*****)

Date 06-25-2007 17:49 Edited 06-25-2007 19:09

My type of subatomic particles for sure!!! ;) ;) ;) If everything goes as planned, a new, actually very oldin relation to just before the "Big Bang" occurred - type of matter is formed but for only a brief period of relative time: 0.00000000000000000000001 seconds. The temperature inside a RHIC collision is over trillion degrees, far hotter than the center of the sun. Talk about "hot stuff"!!! The explanation of how "Quark Gluon plasma" turns into "hadrons" as it coools very quickly and then nucleosynthesis (nuclei), then finally atoms are formed based on time and temperature is simply fascinating to me as I'm sure it also would be to others like Stephan and anyone else that's into different types of physics as in this case we're talking about nuclear physics. And I almost forgot to mention the term... "The "Perfect" Liquid"!!! WOW!!! Now that's some soup!!!Let's not forget to mention the particles called "Mesons" and "Baryons" that groupings of quarks held together by the gluons. Talk about sticky stuff!!! ;) ;) ;)

Anywho, Here's the website:
http://www.bnl.gov/rhic/
Here's the physics primer to us novices better understand what's really going on:
http://www.bnl.gov/rhic/primer.htm
Here's the actual physics of the RHIC or Relativistic Heavy Ion Collider:
http://www.bnl.gov/rhic/heavy_ion.htm
Here are some fascinating facts regarding the RHIC:
http://www.bnl.gov/rhic/fascinating.htm

This is for Stephan or anyone else interested in the latest advances in the physical universe:
http://www.aip.org/pnu/2005/split/757-1.html
Here's the article regarding the RHIC findings titled "An Ocean of Quarks.":
http://www.aip.org/pnu/2005/split/728-1.html

Here's BRAHMS experiment team's white paper:
http://arxiv.org/PS_cache/nucl-ex/pdf/0410/0410020v1.pdf
Here's the PHENIX experiment team's white paper:
http://arxiv.org/PS_cache/nucl-ex/pdf/0410/0410003v3.pdf
Here's PHOBOS:
http://arxiv.org/PS_cache/nucl-ex/pdf/0410/0410022v2.pdf
Finally, here's the STARexperiment teams' white paper:
http://arxiv.org/PS_cache/nucl-ex/pdf/0501/0501009v3.pdf
Enjoy the data Stephan and others interested in this stuff!!!

Talk about opening a can of worms or pandora's box!!! Fascinating to say the least!!!

Respectfully,
Henry

By thesmiths1969 (*)

Date 06-29-2007 10:07

ssbn727 wow the can you have opened must be the size of a small country in Africa lol
Cheers Andy

By Joseph P. Kane (****)

Date 06-29-2007 12:41

Wow! When I look at that, Thank goodness I didn't give out Steve Kane's home phone number!

By Stephan (***)

Date 07-13-2007 14:21

Henry!

Excellent...

Where have I been, that I see this but now!?

Once again YOU are the one who made my day!

Muchos saludos mi amigo ,
Stephan