Abstract
The induction sintering has been studied using ring shaped Iron-graphite mixed powder compacts heated at 50 and 200 kHz. The compacts were heated rapidly and uniformly by choosing a suitable heating pattern and induction frequency.
The experimental results are summarized as follows:
1) In a case of low sintering temperature (≤1150°C) or low graphite content (≤1.5%), the sintered compacts show low transverse rupture strength because of insufficient contacts between iron particles. Graphite diffuses into the iron particle in short time and the microstructure of such sintered compacts shows pearlite including 5-10% ferrite.
2) However, high transverse rupture strength which often reaches above 60 kg/mm2 is observed at sintering temperatures above 1200°C and above 1.5% graphite content. Since the liquid phase exists and graphite diffuses into iron particle during sintering, the microstructure obtained shows pearlite with free cementite which forms network as increasing sintering temperature.
