Flame Hardening of Large Components

Physico-chemical mechanism of action

Flame hardening increases a workpiece's surface hardness by brief gas torch heating followed by spray quenching. The high temperature surge expands the crystal structure, boosting hardness.

Metallurgical relevance & risks in welding

Too fast or too intense flame hardening can cause surface melting and cracks. Too little hardening reduces wear resistance. Control gas flow and quenchant precisely.

Workshop practice & instructions

Use a gas torch with a fixed temperature control knob. Heat for 30 seconds, then quench in a spray bath. Set gas flow so the surface barely glows without melting. Monitor temperature and quench duration continuously.