Nonmetallic inclusion evaluation method of the rustless steel which

摘要

PPROBLEM TO BE SOLVED: To provide an inclusion evaluating method capable of rapidly and accurately evaluating a harmful inclusion in stainless steel. PSOLUTION: The nonmetallic inclusion in a sample is surfaced by dissolving the sample extracted from a stainless steel material by arc in a non-oxidizing atmosphere, the whole inclusion area ratio of the nonmetallic inclusion surfaced and collected on a surface after cooling is calculated, and the harmful nonmetallic inclusion in the stainless steel material is evaluated using the whole inclusion area ratio. The evaluation of the nonmetallic inclusion means estimating the inclusion mass ratio of the harmful nonmetallic inclusion in the stainless steel material using a calibration curve showing the correlation between the mass ratio of the nonmetallic inclusion where the CaO concentration in the prepared sample before dissolution is 25 mass% or higher and the whole inclusion area ratio of the sample surface after the dissolution. PCOPYRIGHT: (C)2009,JPO&INPIT