OK, I said tempering, and could just as well have said hardening, but in any case, isn't tempering essentially the process I described?
Tempering, according to ehow:
http://www.wikihow.com/Harden-Steel or
http://www.ehow.com/about_5627827_definition-tempered-steel.html
Wiki:
http://www.wikihow.com/Temper-Metal
BTW, I am not looking to **** heads with anyone. Just a friendly discussion. I posted my question simply because I noticed that bedframe steel does seem to be 'harder', and less friendly to weld. I will try the annealing process first, and see if it welds better than a piece from the same rail, untreated.
The processes are similar in a way but are not the same at all. After looking at the links you posted I see why you think that. What you describe here is hardening not tempering:
"
Hardening metal, (called tempering), is accomplished by heating metal to a high temperature, and keeping it at that high temp for at least a certain minimum time period (many minutes), then plunging it into cool (room temp) water bath.
The SUDDEN cooling is what hardens the metal. "
The first link you posted does a good job describing the process.
http://www.wikihow.com/Harden-Steel
The second link *****, its confusing:
http://www.ehow.com/about_5627827_definition-tempered-steel.html
clip from the page:
"The main function of tempering something is to add
strength to the material. Tempering is a technique involving heat treatment that is used to
toughen steel. For steel to be tempered, it must be heated up to a specific temperature range and rapidly cooled by being submerged into water. Steel can only be tempered if high amounts of carbon are already present within the steel."
The words strength and toughen are not a very good way to describe metal.
here is why
Reducing the hardness is accompanied by an increase in ductility and vise versa. The more ductile the more malleable and flexible the alloy gets.
The greater the hardness the more brittle and ridged the alloy gets.
The third kinda ***** too:
http://www.wikihow.com/Temper-Metal
It shows a phase diagram and does a piss poor job describing how to use it, if that. To further throw things off it shows a picture of someone working the metal with a hammer lol not sure why it show that.
Clipped from the page:
“Some pieces are very fragile and some applications need a very hard metal piece like a bicycle’s axle or gears or a hammer or simply a screw driver. Tempering consists of heating the steel to a specific temperature
(below its hardening temperature), holding it at that temperature for the required length of time, and then cooling it, usually instill air. The resultant strength, hardness, and ductility depend on the temperature to which the steel was heated during the tempering process. I‘m going to show how to do this tempering. It's very simple and you will have a good results.”
Poor way to write this part. With “(below its hardening temperature)” the writer is meaning the lower transformation level/temperature. If your not familiar with isothermal transformation diagrams and metallurgy this can sound like a hardening heat treatment. I actually missed that when I first read the page and thought this page was describing hardening and nothing about tempering. Darn near made myself sound like a ******* and being up since 4am is not helping
Ok, lets see if I can do better at explaining it now.
Tempering drawsback the hardness making the metal less brittle and a little more ductile and reducing the stress in the metal. Lets say a knife blade, you want it flexible so it will not break but you also want it hard to hold an edge. If you harden a good blade to the max it will be brittle and can shatter like glass. So tempering removes some of the hardness and in turn increasing the flexibility of the blade and now you have a blade that will hold an edge and be flexible at the same time.
Ok, now one would ask/say just harden it to that point, you can't.
The only way to harden the metal is to heat the metal above the
upper transformation level/temperature then quench, but doing this the ductile/flexible goes away. To get part of this back a tempering heat treatment is done, heating the metal to/under the
lower transformation level/temperature and then quenched again or allowed to cool slow what ever the heat treatment calls for.
Hope this helps and not further confuse.