IDIOTS GUIDE DEFINITION

[agpowder]

Hello, I own a business that makes a plastic product and we are using self designed and made extruding machines.
As part of our "machine design improvement" process we have come around to improve the quality of steel used, by heat treating and I am now coming across terms I only very slightly understand, however as I am paying for these processes I would like to just have a little more understanding or confirmation than I presently have, in particular four terms keep coming up from the engineers that I have, these words are (and my simple definition is):
Normalizing: bring the metal into a condition where it can be worked. Word interchangable with Annealing. done by heating to a glow and left to slowly cool.
Quenched: putting the part into water or oil to cool rapidly. word interchangable with Chucked.
Tempered: Heating a part to a temp around 400 to 600 degF and left there for a period of time and then quenched (or chucked) into oil or water. Temp and time is dependant on the desired hardness/tensile strength.
Hardness and tensile strength and yield strength are pretty much directly proportional to each other.

I am not wanting anyone to define further but to tell me I am pretty much right or wrong.

 

[TVP]

As a first pass, you are pretty much right rather than pretty much wrong. Normalizing isn't the same as annealing, but they are similar when compared to other processes like neutral hardening or carburizing.

 

[agpowder]

Thanks for you reply TVP. Am I right in saying?: "The method of hardening that we use is tempering, other methods of hardening are neutral hardening and carburizing"

 

[Robertmet]

Briefly, Normalizing is heated above critical temperature, air cooled, Annealed is heated above critical ,slowly cooled in furnace or vermiculite.
'Chucked' we don't use ! Quenching maybe in air, oil, polymer solution, water, brine.
Temper is done for 1 hour or more at anywhere from 300F-1200 F.There is no need to quickly cool ,water etc, after quench.
These are for steels and every steel is different and the HT is adjusted for the steel and application.

 

[TVP]

agpowder,

Not quite. Neutral hardening means austenitizing (heat to T ~ 1550 F or higher) in a furnace with a controlled carbon composition that does not cause addition or removal of carbon from the steel being processed. This is followed by quenching and tempering to process most steels, and is the method that you are using. Carburizing and nitriding are examples of other hardening methods.