View Full Version : Steam Tempering

Richard P Wilson
11-29-2013, 07:20 AM
I've just received an advertisement from a UK supplier for drills described as 'HSS P1 Steam Tempered' What in the world is 'Steam Tempering', I've never heard of it.


11-29-2013, 09:34 AM
No obvious google references, but I would suspect steam would be used to precisely control the tempering or draw temperature very accurately.

With modern steels I'm not sure why that would be necessary as the alloy is often used to control the hardness the without requiring close temperature control.

for for temperatures at pressures see:


11-29-2013, 09:42 AM
They do use superheated steam for some applications, its rare as H2 embrittlement was stated as an issue, never tried it, don't like autoclaves much.


Edwin Dirnbeck
11-29-2013, 10:21 AM
Some drills have a black color that is produced by a ''steam oxide surface treatment of drills'' Edwin

11-29-2013, 11:11 AM
Maybe they are on to something, then again------------------------------

11-29-2013, 12:31 PM
Have not heard of the term either but a quick look found this.


Steam tempering: The production of a stable oxide on steel parts by treatment in steam at about 300oC. Improves corrosion performance and reduces friction.

11-29-2013, 12:36 PM
Well, even though steam will work and be very predictable, I think that a molten salt bath would be vastly superior.

Modern electronics and controls would allow for very accurate control of salt bath temperatures and would not allow surface oxidation to boot.

go to "Salt selection consideration: "
found here:
for their temperature ranges... seems to cover everything available with autoclave without the steam...