Will This Furnace Work For Heat Treating?

[benmychree]

Thanks Flammable. Sounds like I better stay away from the door. Just out of curiosity, say I was heat treating a 1-2-3 block. Would there be any good reason to put the block in the furnace at ambient temperature, then ramp the temp up to the set point, let it soak, then remove it? I.E. does the work HAVE to go into a hot furnace, or can it go in a cold furnace and heat up as the furnace does? Thanks.

Bob

Anything that I have ever seen or read, stresses that to avoid thermal shock, work to be heat treated should always go into a cold furnace and come up to temperature gradually; that is the way I have always done it.

 

[frostheave]

Anything that I have ever seen or read, stresses that to avoid thermal shock, work to be heat treated should always go into a cold furnace and come up to temperature gradually; that is the way I have always done it.

Thanks benmychree. In the videos I have watched, it looked like the work was put into a furnace that was already at the soak temperature. Or, maybe I haven't been watching that closely and just assumed it was already up to temperature. Anyway, starting the work and the furnace cold then heating them both up, as you do, sure makes sense to me.

Bob

 

[pdentrem]

We start with a hot box. Since we might be making a few tools through the day, we leave the oven on at the desired set point all day. The stresses are produced during the hardening stage and this is why tempering is a critical step. Ray C has alluded to this and to normalization in his large topic that he posted earlier.
Pierre

 

[Flammable_Solid]

Thanks Flammable. Sounds like I better stay away from the door. Just out of curiosity, say I was heat treating a 1-2-3 block. Would there be any good reason to put the block in the furnace at ambient temperature, then ramp the temp up to the set point, let it soak, then remove it? I.E. does the work HAVE to go into a hot furnace, or can it go in a cold furnace and heat up as the furnace does? Thanks.

Bob

The metallurgist answer: it depends on what the material is, the current heat treated state, and what you are trying to do.

The refractory in your furnace has a much lower heat capacity than the metals you are going to put in it. With no load in it, open the door for 30 seconds, then close it, and monitor how long it takes to recover to the set temperature.

Repeat that with a thermocouple embedded in a piece of metal matching your parts. It takes a lot longer.