Process for producing carbon fibers

摘要

Carbon fibers are produced by continuously heat-treating acrylonitrile fibers up to the crystal collapse starting temperature of said fibers while maintaining said fibers under a fixed length or tension in an oxidizing atmosphere, then sufficiently thermally stabilizing fibers by further subsequently continuously heat-treating them in a temperature range gradually elevated up to a fixed temperature in a range of from a temperature about 20 DEG C lower than the deterioration starting temperature of said fibers to a temperature about 20 DEG C higher than said deterioration starting temperature in an oxidizing atmosphere. The thus sufficiently thermally stabilized fibers are treated with a reducing liquid and subsequently carbonized or graphitized in a non-oxidizing atmosphere or under a vacuum.