Talk:Cast iron

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Plural kelvins[edit]

Mr. Nygaard: Sorry about the plural thing. I imagine I seemed stubborn and rude, but in fact I didn't know how to use the site, and had no earthly idea that it had been chanced back those times. I say something is "at 300 Kelvin" or "10 Kelvin" all the time at work, but I guess differences could be expressed as "Kelvins"...I'm certain that "degrees Kelvin" is correct in both cases. Anyhow, sorry for the trouble. User:Polyparadigm

Yes, what you describe happens often enough. But that usage is clearly a failure to understand a change in the rules, not something sanctioned by any of the keepers of our standards—and in this case, it is the linguistics standards that apply, not the metrological standards beyond the fact of the basic dropping of degrees and changing the official symbol.
Back in 1967 the CGPM dropped the degrees which were used as the noun for these units, with Kelvin used as an adjective to identify the degrees, and changed the symbol from "°K" to "K".
The capitalization rules are different for nouns and adjectives in English. The names for units of measure named after people (watt, newton, volt, etc.) are not capitalized. But it is a quirk of English usage that when proper adjectives are used to identify a particular unit when the name of the unit standing alone is ambiguous, then those adjectives are capitalized. FOr example, degrees Fahrenheit", "degrees Celsius", "Gunter's chain".
Furthermore, when "Kelvin" was used as an adjective, it did not change in the plural; the "s" was added to "degrees" instead in the term degrees Kelvin. After the change, we add the "s" to the new noun.
Many technical people are less proficient in the language-related issues, and fail to understand the significance from this change from "Kelvin" as an adjective in "degrees Kelvin" to "kelvin" as a noun in "kelvins".
Another source of confusion, which applies to Wikipedia contributions by some non-native speakers of English, is the fact that the rules for spelled-out words are language-dependent, generally not determined by the keepers of the standards. This differs from the rules for the symbols for these units, which apply worldwide. Italians have their chilogramo but its symbol is "kg" as it is for everyone else, for example, but more to the point, in German "300 Kelvin" is quite proper. That's because of both different rules for capitalization (all nouns are capitalized), and different rules for the plurals of all measurements, generally using the null plural, saying "Es ist 2,5 Meter hoch" ("It is 2.5 meters high") as well. — Gene Nygaard 14:42, 24 Jan 2005 (UTC)

I would like to say, out of 4 weeks of intensive research on combustion and related materials, this is the best written article on a complex topic I have read. Clear, concise and complete. Thank you very much for your contribution. Still need to find actual values of thermal conductivity for Cast Iron... PSU Engineering Dropout

I would only agree that the article is presented well. There are errors in the article and additional references are needed. Some somments may be original research. Mfields1 (talk) 15:28, 4 January 2009 (UTC)


I have expanded the article by adding a section on the uses of cast iron. However I have only carried the history of this up the the 19th century. Would some one else like to expand this to bring it up to date? Peterkingiron 23:08, 14 May 2006 (UTC)


"The exceptionally high speed of sound in graphite gives cast iron a much higher thermal conductivity."

Could someone explain this? Seems to make no sense to me. User:Pedant 17:21, 6 October 2006 (UTC)

Indeed, I was coming to comment on the same thing. --Belg4mit 16:57, 23 October 2006 (UTC)
Yeah, this sounds like some mix up of words. I did a little researching in graphite, thermal conductivity, and speed of sound with no info regarding this. A google search also showed nothing. I think it should be something along the lines of "The speed of sound through graphite and higher thermal conductivity of graphite account for these characteristics in cast iron." --Wizard191 (talk) 01:05, 10 January 2008 (UTC)
I added a request for a reference to this. Cast iron is generic and can refer to gray iron, ductile iron, malleabe iron and alloyed irons. The graphite shape is different according to the major type of iron class. The velocity of ultrasonic waves can be related to the graphite structure. In short, sound will attain velocities of 5500 to 5800 m/s in ductile iron (for example) whilst in gray irons the ultrasonic velocity is typically less than 5000 m/s. Gray iron has a higher thermal conductivity which is related to the length and shape of the graphite structure. I added the request so that someone can provide evidence to the relationship of the speed of sound in iron to the thermal conductivity. If found this citation can be added and the note removed.Mfields1 (talk) 15:26, 4 January 2009 (UTC)


This section is insufficently detailed/meaningful to warrant inclusion. --Belg4mit 16:57, 23 October 2006 (UTC)

If you know more, please expand it. Peterkingiron 17:27, 17 December 2006 (UTC)

Merge Proposal[edit]

Object - the section is appropriate here. I am merging the section to which the merge is proposed into a new History of Ferrous Metallurgy, but will probably refer back to this article. However, more on the modern uses of cast iron, and its use by the Chinese in antiquity would be appropriate. Peterkingiron 17:27, 17 December 2006 (UTC)

Cast Iron Bridges[edit]

I'm not in the know but my instincts tell me that 'iron' and 'bridges' should be lower case because the section is talking about cast iron bridges in general, which happens to also include the Iron Bridge. --Wizard191 (talk) 01:20, 10 January 2008 (UTC)

Cast iron use in bicycles[edit]

The Brompton Bicycle article claims that the hinges of this folding bicycle are made of cast iron, with no reference. Initially I thought that this would be too brittle, but after reading this article It seems that it would be feasible, but I still have my doubts. Can steal and cast iron be brazed together as it implies? If not, is there some other way it could be joined. Anyone more knowledgeable about metallurgy have any input?--Keithonearth (talk) 03:01, 25 December 2008 (UTC)

Depending on the grade of cast iron, it is completely possible, although, IMO, odd. Steel and cast iron can definitely be brazed and even welded (see [1]). Wizard191 (talk) 22:58, 25 December 2008 (UTC)

Thanks for the info. It's good to know. --Keithonearth (talk) 08:21, 26 December 2008 (UTC)


I removed the "invented by Chinese" stuff and clarified that a cupola is not the same thing as a blast furnace. —Preceding unsigned comment added by John Chamberlain (talkcontribs) 23:21, 10 February 2009 (UTC)

some at% figures for perspective?[edit]

Shouldn't this article try to fit in some at% figures to give perspective to some readers? 5 wt% carbon doesn't sound like much to nontechnical readers who may momentarily forget how just how much carbon there is in a 5 wt% solution in iron, molar-wise. John Riemann Soong (talk) 10:01, 12 November 2009 (UTC)

Sure, go for it. Wizard191 (talk) 16:35, 12 November 2009 (UTC)

Table of comparative qualities of cast irons[edit]

I started to edit some misleading figures in this table but this will be a big project. Firstly it refers to ASTM specifications which are nice for U.S. readers but ignores ISO, JIS or other standards. The table is in ksi and not in SI units. Also the figures are misleading because there is a wide variety of strength grades for gray iron, ductile iron and malleable irons. The same is true for austenitic irons. This needs a lot of work if a table such as this does not have some disclaimers. Also to call it a table of qualities is a biased term. It seems to be a table of mechanical strength properties.Mfields1 (talk) 02:26, 20 November 2009 (UTC)

While the table is not exhustive by any means, its better than nothing. If you want to supply a table with ranges of properties for various standards or types that would be greatly appreciated. Wizard191 (talk) 23:08, 26 November 2009 (UTC)

Welding of Cast Iron[edit]

While I agree that the unqualified statement on welding should have been modified, I don't think it is a good idea to remove it completely. The problems with welding of any irons within the family of cast irons are 1) the graphite can cause microstructural changes to the matrix that must be accepted or dealt with, 2) suitable filler metals must be used which will rarely or never match the base iron microstructure (leading to strength degradation and sometimes poor color match) and yhe castings can crack if suitable preheating countermeasures are not employed. While cast iron may not be the most difficult alloy to weld it ranks very high in this regard. Mfields1 (talk) 02:35, 25 November 2009 (UTC)

I can't remark on the weldability of all cast irons, but I removed that remark from the gray iron section because I found this reference which states: "Gray cast irons are usually easy to machine and weld". I've never tried to weld cast iron so I can't personally remark on it, so I'm just going off the ref. Wizard191 (talk) 14:05, 25 November 2009 (UTC)

hi i am asking all of you aut there what is cast iron made of?if you know please post a comment on this talk. —Preceding unsigned comment added by (talk) 18:03, 2 November 2010 (UTC)

Grammar Error?[edit]

Is the word "flammable" being used correctly in the "Textile mills" section?

According to Strunk & White (third edition, pg 47), the word "inflammable" should be used instead. Anonymous440 (talk) 19:52, 1 December 2011 (UTC)

Yes. Strunk and White isn't an authority on meanings, just on one antiquated view of US grammar. It's not well regarded in the UK at all - I keep mine mostly as a dire warning.
As to flammable/inflammable, then it's complicated, but generally they're interchangeable. Where inflammable has any formal definition, it's in relation to the temperatures at which a vapour can be ignited - this certainly isn't the case for timber. Andy Dingley (talk) 20:29, 1 December 2011 (UTC)
While inflammable is considered better English, flammable is preferred wherever safety is involved, to avoid misunderstanding by non-native speakers. (Just found a link). Materialscientist (talk) 22:28, 1 December 2011 (UTC)

Can someone explain to me what this sentence is supposed to mean?[edit]

"The alloy constituents affect its colour when fractured: white cast iron has carbide impurities which allow cracks to pass straight through..." — Preceding unsigned comment added by (talk) 12:22, 6 June 2012 (UTC)

Clarification requested under Ductile Cast Iron[edit]

It says "magnesium or cerium added to these alloys". It would be helpful to clarify which alloys are being referred to. Thanks. — Preceding unsigned comment added by Craniator (talkcontribs) 15:14, 8 August 2013 (UTC)

Malleable (cast) iron[edit]

Be aware of the problem that "malleable iron" has two distinct meanings: Either the same as "malleable cast iron" or "wrought iron". I think tne first is American and the second British. (talk) 11:21, 25 September 2013 (UTC)

Does cast iron resist warping?[edit]

Can anyone comment here on whether or not cast iron tends to resist warping under heat (more than certain kinds of rolled steel)?

And, if this is so, it might be worth adding something about this quality of cast iron to the article.Joel Russ (talk) 06:16, 7 January 2014 (UTC)

If anything, it's worse. Especially if you regard "warping" as "taking a permanent set that remains after cooling". Andy Dingley (talk) 11:13, 7 January 2014 (UTC)