Disadvantage of using brine to quench

A Korean swordsmith, when asked if he used salt water to quench his blades, scoffed at the idea, saying that the salt would corrode the steel. Is he simply wrong? Salt certainly is corrosive. If he is right, is brine used because the corrosion is minor or only a factor in the long run, because there are ways of counter-acting or elminating the corrosion, because other people ignore the corrosion problem, or what?

No, brine won't 'corrode' the steel, unless you leave it in for a year or so. Brine is a fast quench; faster than water and much faster than oil. Brine is satisfactory for plain carbon steels, the SAE 1000 series. The main advantage of a fast quench is control of grain size; the faster the quench, the smaller the grain. Brine is unsatisfactory for high alloy steels, which usually require oil. I've had 5160 literally tear itself apart in the tank with water and brine. It contracted so violently that it shattered; intergranular tensile failure. With the right steel, it's the right quench. With the wromg steel, it's scrap. Hope this helps...

Charly