So far as the grain size order of magnitude is concerned, the thickness of the acicular ferrite is about 200nm, while the thickness of the austenite existing inside the ferrite is only several nm to 10 nm.

• 从晶粒尺寸数量级来说，针状铁素体的厚度约为200纳米，而铁索体内奥氏体的厚度仅为几到10纳米数量级。