Talk:Tempering

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i don't understand the reference to music.

is there such a thing as cryogenic tempering? - Omegatron 17:23, May 26, 2005 (UTC)

Traditional blacksmiths sometimes use music to time their processes; waiting too long leaves a soft product, too little time means brittleness, so a repeatable process was necessary, and a song is easy to teach and to reproduce, without requiring any equipment or even the use of one's hands.

In the strict sense of the word, there is no such thing. Cryogenic treatments can have a profound effect on the "temper" (loosely speaking) of certain steels if their composition and prior heat treatment are such that they retain some austenite at room temperature, but that process is not time-sensitive at all. The transformation from austenite to martensite (mostly accomplished through quenching) is driven farther and farther as temperature decreases, which leads to more of the harder component; in higher-alloy steels such as austenitic stainless steel, this can require very low temperatures indeed. However, (1) the transformation between these phases is instantaneous and not driven by diffusion at all, and (2) this treatment causes more complete hardening rather than moderating extreme hardness, both of which make the word "tempering" technically incorrect. Perhaps I should make this more clear in the article on martensite. I wanted to make a more complete heat treatment article, but time constraints and the opinions of prior contributors have prevented me from doing so.--Joel 21:24, 26 May 2005 (UTC)

Come to think, I should just make up an article on cryogenic hardening, and put in a link from the second paragraph.--Joel 21:32, 26 May 2005 (UTC)

[edit] Tempered glass

This article doesn't cover tempered glass. Does an article already exist, should it be added here, or should another article be started? -- Kjkolb 05:08, 19 December 2005 (UTC)

There's a section on tempered glass referenced on the disambiguation page for temper. Is that adequete? Tom Harrison ^(talk) 13:58, 19 December 2005 (UTC)

Hmm, I don't know how I missed that. Thanks, Kjkolb 16:07, 19 December 2005 (UTC)