高硬度鋼の疲労強度に及ぼす表面仕上げの影響 : 炭化けい素およびダイヤモンド砥粒の場合

抄録

The quenched and tempered carbon tool steel (SK 5, about 750 Hv) was polished with a silicon carbide abrasive paper or a diamond abrasive cloth, in a wet condition. Observations revealed that most of the cracks originated at slip bands in surfaces polished with silicon carbide abrasive paper, after a fatigue test, whereas in the surfaces polished with diamond abrasive cloth, fatigue cracks originated from inclusions. Besides this fact, several differences between the surfaces polished with silicon carbide abrasive paper and those polished with diamond abrasive cloth were perceived from other observations and measurements. The above-mentioned facts suggest the necessity of taking the kind of abrasive grain and adhesion to paper or cloth into consideration in preparing standard specimens for fatigue tests which are frequently finished by polishing. In addition, it is required to state what abrasive grain and adhesive were used when presenting fatigue test results.