probably not. A big issue today , in the case of advanced alloys ( P91, P112, etc) is that the required heat treating temperature has extremely narrow limits, + /- 30F. There are large temperature gradients in most furnaces , in excess of +/ - 30 F, unless one uses a hot gas recirc fan, so the old furnaces would not reliably treat the advanced alloys
It greatly depends on the type of furnace, the type of parts to be heat treated, the heat treating function being performed, and the definition of used. Stress relieving and hydrogen embrittlement relief of small mechanical components at low temperatures is quite different from multi-step carburizing heavy section gears or shafts.
If I remember correctly, you previously indicated your company is investigating heat treating tool steel in-house. If this is related to that investigation, then a partial list of items with which to be concerned are as follows:
1. Temperature uniformity
2. Atmosphere control
3. Design of quench system
Heat treating furnaces require a great deal of expertise to be properly set-up. If you are considering purchasing something that is used, but it still comes with manufacturer support for set-up, calibration, etc., then this may be a very good idea. Otherwise, buyer beware...
The furnace will not be used for mission critical applications, just quick and dirty urgent work where time is critical. Also this furnace would be used for Precipitation Hardening of 17-7 and some Ni-based alloys.
I'm certain that it's not cost effective to attempt becoming a heat-treat house.
We bought one recently, and have never had any problems with it, its a expensive drop down furnace, about 1.5 x 1.5 x 1.5. This has never had any problems, and has been calibrate to aerospace standard, and passed every time. THe control limits set for the calibration are +/- 5oC.
I would say that before buying ask to see a relevant calibration cert, if this is okay along withthe history, then i should see no problem.
