Talk:Cryogenics

message: The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cryogenic” by accepting a threshold of 120 K to distinguish these from the conventional refrigeration.  — Preceding unsigned comment added by 37.157.176.194 (talk) 01:07, 12 November 2020 (UTC)
thread_title: Definition

message: This article is rather vague and light on facts. It needs more content to actually be useful. For instance, a table listing common cryogens (liquid helium, liquid nitrogen, liquid argon, etc.) with their boiling points would be very useful.  —Preceding unsigned comment added by 74.104.23.49 (talk) 00:50, 3 December 2010 (UTC)
thread_title: Please add Actual Cryogens

message: It seems the second half of this article is little more than advocacy. —Preceding unsigned comment added by 128.237.241.229 (talk) 19:56, 8 February 2005 (UTC)
thread_title: Advocacy

message: WHERE CAN I GET MORE INFORMATION ABOUT CRYOBIOLOGY OTHER THAN IT IS THE STUDY OF LVING STUFF AT LOW TEMPERATURES ???!!!???!!! —Preceding unsigned comment added by 203.220.220.209 (talk) 06:39, 16 September 2004 (UTC)
replies: text: You will probably not find a lot about cryobiology, because truthfully not many biological processes happen at low temperature.  It is, in essence, the study of what doesn't happen at low temperatures (from a biological perspective).  Most of the legitimate research would likely be in the area of microscopic cryopreservation (like proteins, cells, etc), in situ cancer treatment, and in the area of food science.  The more macroscopic varieties (e.g. freezing Walt Disney or Ted Williams's head) are generally considered pseudo-science. —Preceding unsigned comment added by Arencibia2 (talk) 19:30, 12 October 2005 (UTC)
thread_title: More information sought

message: If the study of low temperatures is Cryogenics, then what's the study of high temperatures? Hugh Jass 02:04, 30 September 2005 (UTC)
replies: text: There is not a corresponding study of high temperatures analogous to cryogenics.  The reason is that at low temperatures, not many things happen.  So, to generalize, low temperature science is somewhat unified and reaches a single point (absolute zero).  At higher temperatures the interactions of matter become more energetic and more varied.  Thus there are many fields of study.  Some specific fields of study would be combustion, high temperature plasma physics, kinetics, nuclear fusion, etc.  Higher temperature sciences diverge to many areas. —Preceding unsigned comment added by Arencibia2 (talk) 19:30, 12 October 2005 (UTC)
thread_title: Study of high temperature

message: *Removed line 'cryonic sucks!' from Etymology. --24.75.229.66 15:11, 16 March 2006 (UTC)
thread_title: Etymology

message: NPOV: Removed "pseudo-science" description from cryonics.  The paragraph below that location adequately describes cryonics as fringe. —Preceding unsigned comment added by 66.10.26.253 (talk)  15:57, 17 April 2006 (UTC)
thread_title: Fringe

message: What we see here are incorrect statements rewritten from the literature of companies like "300 Below", etc.  Heat treated (sound, solid) metals don't have molecular structure as stated below.  Ask any student of materials engineering/metallurgy department from any country to correct these statements on heat treating of steels and non-ferrous metals and, also, add related info regarding the completion of martensitic transformation in sub-zero temperatures, residual stresses, and/or stress-induced, 2nd phase precipitation.  There are also ASM handbooks and numerous technical publications (conference and peer-reviewed) dealing with the subject of cryogenic metal treatment.  
"The theory was based on how heat-treating metal works (the temperatures are lowered to room temperature from a high degree causing certain strength increases in the molecular structure to occur) and supposed that continuing the descent would allow for further strength increases. "
—Preceding unsigned comment added by 24.229.203.154 (talk) 01:43, 28 February 2008 (UTC)
thread_title:  factually incorrect 

message: Do you think a cryogenic bomb would be possible? You know, a bomb that freezes its surroundings to ice. I've looked for an answer to this question, but haven't found anything.  —Preceding unsigned comment added by 81.8.238.23 (talk) 01:35, 20 July 2008 (UTC)
thread_title: cryogenic bomb

message: This article has been marked since December 2007, over a year at this point, for not having any citations. Surely, someone must have access to copies of Advances
in Cryogenic Engineering which has been published annually since 1955, and by now must have more than fifty volumes. Is there anyone out there from the Cryogenic Society of America (CSA)? --Bejnar (talk) 23:38, 4 January 2009 (UTC)
thread_title: Citations

message: I am going to agree with the author of "Factually Incorrect" that the section on the cryo-treatment of metals is full of errors. Take the sentence commented on earlier"
"The theory was based on how heat-treating metal works (the temperatures are lowered to room temperature from a high degree causing certain strength increases in the molecular structure to occur) and supposed that continuing the descent would allow for further strength increases."
Start with "The theory". No theory was offered, and the rest of the sentence basically says that if cold is good, colder is better, for pretty much everything.
Second, metals and ceramics do not contain molecules. In terms of chemical composition, alloys are simply impure metals. There is no fixed ratio of one atom to another to make them either molecules or compounds. Even the small amount of carbides and such in metals are not molecules. They are compounds. Same for SiO2, NaCl, etc. Polymers are made up of molecules.
Thirdly, how heat treating works is very different for different materials, and the goals of these heat treatments vary. They can be used to strengthen, or soften, etc. Some heat treatments are multi-step, some require rapid cooling, some soaking at temperature, and so on. There is no one theory on how heat treatments work.
Overall, the article makes it sound like most of not all metals can be improved by cryo-treating. The original work was done on tool steels. Tools steels contain a significant amount of additives such as Ni and Mo that stabilize the high temperature phase of iron called austenite. Upon cooling significant amounts of austenite are retained after cooling to room temperature. Cryo-treating was developed to further reduce the amount of retained austenite. Many stainless steels are austenitic due to their high Ni content and cooling them well below room temperature can start the austenite-martensite reaction. 
But what if the metal does not contain austenite? Say, ordinary cast iron, or copper-based or aluminum-based alloys. How would this work. All we have is speculation, basically that thermal contraction might lead to localize cold working in particle-strengthened alloys. But if you read the literature and web sites at cryo-treating companies you'll see vague and often grossly wrong descriptions (i.e. austenite is a brittle carbon-carbide) of the process for steels, then they will skip on to the other alloys as if it worked the same for them, and even plastics.
I once conversed with a guy who ran a cryo-treating service and advertised his services in the SCCA (motorsports) publication, offering to help clean up his carbon-carbide text (he was not the only site saying this. I believe OneCryo was doing the same back then, but have since changed that.) After he got past calling me a book-type and all that nonsense (I am a book type, and I build my own cars.) he did explain that the treatment involved slow cooling, soaking, then slow warming, followed by a short heat treatment. The process was similar for cast iron parts, forged steel, coppers and even soft bearing materials. I asked if he had ever done the heat treatment alone, without the cryo, and if so had that yielded similar results. He hadn't. Given that the metallurgy of cryo is dead wrong, and that heat treatments he described could do nearly all that the benefits of cryo-treating are supposed to offer, I think that the heat treating does the trick. In fact, from all of the descriptions of cryo-treating I have seen, none will stress relieve a part. Only heat treating will. 
To me, this nonsense is like if you went to your local new age hoo-doo doctor and were given a thorough karma massage and an aspirin and afterwards you felt better and credited it to the wonders of new age medicine.
By the way, the paragraph that covers cryo-milling should be separated from the metals part. Cryo-milling IS real.
M610 (talk) 00:50, 24 September 2011 (UTC)
thread_title:  Still factually incorrect 

message: Up until recently, "cryo" was associated with the freezing temperature of water. With that in mind, if a substance boils or sublimates at-or-below the freezing temperature of water, at Sea Level pressures, it is-or-was considered to be cryogenic; historically speaking!  
A good example is Butane; a paraffin oil that boils at -1°C. You can hold a puddle of Butane in your hand while it boils away; incurring only minor, superficial frostbite.  Simpler paraffin oils, like Propane, boil at -42°C. Natural Gas is a mixture of paraffin oils: Methane (boiling at -162°C) and Ethane (boiling at -89°C). All of these compounds are treated and classified by industry and government as cryogenic. "Number 5" on the list is Pentane which boils at +36°C, which is above the freezing temperature of water. Therefore, Pentane in not cryogenic, even though it boils at human body temperatures.
Several paragraphs in the applications sections mention substances such as LPG that do not fit the previously-given definition of cryogenic liquids.Parveson (talk) 00:23, 11 December 2013 (UTC)
thread_title: "Cryogenics" begins ''below'' the freezing temperature of water

message: The lede mentions cryogenicists using the Rankine temperature scale. Does anyone actually still do this? My understanding was that the sciences were now quite thoroughly metricated, even in the United States. Seph Shewell Brockway (talk) 11:59, 13 October 2017 (UTC)
thread_title:  Rankine temperature scale? 

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thread_title:  A Commons file used on this page has been nominated for speedy deletion 

message: It's important to show also the medicinal use of cryogenics. 2A02:AA11:9102:3D80:1559:70A7:B3A0:6BD9 (talk) 04:21, 23 March 2022 (UTC)
thread_title:  Cryogenic for biopreservation 

message: This article has to be one of the best in all of Wikipedia.
I Love the Cold, And I want this article to be promoted.  — Preceding unsigned comment added by 2601:5C7:4100:3600:197F:B52D:6070:708C (talk) 14:02, 27 November 2022 (UTC)
thread_title:  Proposal 

message: — Assignment last updated by Thecanyon (talk) 05:33, 12 December 2023 (UTC)
thread_title: Wiki Education assignment: Technology and Culture