The grain size is measured to be above ASTM grade 11.0 for low temperature coiled Ti-IF steel as well as Ti-Nb-IF steel containing higher carbon content or to be about ASTM grade 10.5 for high temperature coiled Ti-IF steel, respectively.

• 热轧低温卷取Ti-IF钢和碳含量较高的Ti-Nb-IF试验钢的铁素体晶粒度在11.；0级以上；热轧高温卷取Ti-IF钢在10