The first step in the hardening process is to heat the steel to the correct temperature for quenching. All tool steels have a critical range, and heating the steel above this critical temperature range is necessary in order to fix, by quenching, the changes desired. Pre-heating is necessary if the tool is large or has heavy and light sec-tions adjacent to each other. After the steel is up to temperature, it should be allowed to heat for at least five minutes per inch of diam-eter or thickness in
preparation for quenching. In other words, if the quenching tempera-ture is 1500 degrees, the furnace should be held at that temperature and the steel allowed to reach this temperature. "A Knights Dragon Fire Heat Treat Furnace with automatic temperature control is ideal for this precision work," said Bill Knight.