(三) 鋼件中的晶粒缺陷我們把鋼件打断,就看到断面是亮晶晶的,好象一顆一顆的粒子聚集起来似的。有的鋼件打断以后,結晶非常細,不容易用眼睛看得出;例如淬火后的鋒鋼(高速工具鋼),打断以后,断面象光滑的油脂。有些鋼打断以后結晶粒子很粗,眼睛可以看得很清楚;象变 (C) the grain defects in the steel We break the steel, you see the section is shiny, as if one by one the particles gathered together. Some steel interrupted, the crystallization is very thin, not easy to see with the eyes; such as quenched front steel (high-speed tool steel), interrupted, the smooth section of oil. Some broken steel after the crystal particles are very thick, the eyes can see clearly; like change