Steel wire patenting: thermal and metallurgical comparison between quenching in lead and quenching in a fluidised bed

Abstract

Patenting of steel wire is a common process whereby the wire is heated to ～950^°C to form austenite, and then rapidly quenched in molten lead held at ～500^°C. The fine-grained structure so formed, patenting sorbite, has high strength coupled with good ductility. However, using lead as a quench medium poses environmental challenges due to its toxicity. An environmentally friendly alternative to lead quenching is quenching in a fluidised bed. The thermal and metallurgical performance of lead quenching is compared with that of fluidised bed quenching. It is concluded that quenching in a fluidised bed can provide similar results to lead quenching for smaller diameter wires.