PRODUCTION OF IRON POWDER FOR GREEN COMPACT MAGNETIC CORE

摘要

PURPOSE:To produce iron powder for a green compact magnetic core having good purity of iron powder, compressibility and interparticle insulatability by holding the raw material iron powder at a specific temp. range in a reducing or non-oxidative atmosphere then cooling the powder in at least a partially oxidative atmosphere. CONSTITUTION:The raw material iron powder is heated and held to and at a 450-800 deg.C temp. range in a reducing or non-oxidative and non-carburizing atmosphere formed by incorporating steam into gaseous hydrogen or hydrogen- contg. gas. The deoxidation and decarburization of the iron powder are thus progressed to increase the purity so that the purity and compressibility are improved. The iron powder is thereafter cooled in the oxidative atmosphere in at least part of the process in the cooling process from the holding temp. to form thinly an oxide film on the iron powder surface by which the inter-particle insulatability of the iron powder is improved. The process from holding at 450- 800 deg.C to cooling is executed in the same atmosphere if the above-mentioned atmosphere is maintained within a dew point 35-65 deg.C range.