hy Belstain,
I'm not the big expert in heattreating, but i have some experiences with kitchen salt and heattreat: i have a gasforge which i can set upright. When fitted with a metal container (in the forge) filled with kitchen salt, it's perfect for heating blades: since the salt melts at about 800°C, it's ideal to get blades (spring steel) at their critical temperature without risks of overheating and decarburisation (the salt works as a protective agent around the blade). After this heating, i quench in oil or fat...
hope this is of any help to you,
tim