Tempering furnaces
Tempering of wire (often alter oil quench) can be done in a specially designed fluid bed furnace. The modifications to the typical design will allow for the necessary cleaning of contamination which is a usual part of an oil tempering installation.
The process reheats the quench hardened steel to the temperatures below the transformation range. This will relieve the martensitic brittleness of the quenched structure. The temperature selected is determined by the combination of desired tensile strength, required ductility and the analysis of the particular finished wire.
In general the higher the temperature of reheating, the lower the strength and the higher the ductility.
Operating temperatures are usually dependant upon the site of the wire and the desired metallurgical properties.