[Mike Kelly]

Low carbon mild steel: normally it isn't suitable for heating/quenching . MS is usually case/surface hardened in an oven with charcoal or casenite powder. For small items a flame and hardening powder is suitable. These days you can buy the modern less hazardous case hardening powder , they used nasty stuff years ago with cyanide or something in it. The TAFE I went to, they had "casenite" hardening powder and a big oven .

The higher carbon steels suitable for quenching have special elements added , its a science on its own and its a complicated topic !