Display Method of Pure Ferrite Structure of Low Carbon IF Steel Sheet

The samples of IF steel (DC06 steel and CR5 steel) were prepared by etching and electrolytic polishing methods. The sample preparation effects of two methods were compared. The influences of the type of etchant and etching time on sample preparation effect were analyzed. The results show that the sample preparation by etching was simpler than that by electrolytic polishing, but the best etching time need to be determined through many tests. The sample preparation process of electrolytic polishing was complex, but the sample preparation effect was good, and the sample with clear grain boundary could be obtained. The etching effects were poor when the DC06 steel and CR5 steel were etched by 4% nitric acid alcohol solution. The clear ferrite grain boundaries of DC06 steel with carbon mass fraction grater than 1×10^-5 could be observed after etching with cupric sulfate hydrochloric acid solution for 6, 10 s. The etching effect was poor of CR5 steel with carbon mass fraction less than 1×10^-5 after etching with cupric sulfate hydrochloric acid solution, and the electrolytic polishing effect was good.