The difference of mechanical properties of rolled CLF-1 steel plate was investigated by the means of chemical analysis, optical microscopy, scanning electron microscopy, transmission electron microscopy and so on. The results showed that the content of major chemical elements of two types of rolled plates were little different and accorded with specification. The grain size of 10mm rolled plate was smaller than 35mm rolled plate. The martensite laths width and volume fraction of precipitates of two plates were 200~350nm, 2.56%, 600~800nm, 1.98%, respectively. Thus, the differences of the primary austenite grain size, martensite laths width, volume fraction and size of precipitates between two kinds of rolled plates are the main reason which induces the variation of plates’ mechanical properties. These differences could be caused by forging and hot rolling deformation and the heat treatment parameters. Therefore, the total deformation of forging and rolling of different thickness plates should be equaled, and the parameters of heat treatment should be strictly controlled during fabricating the industrial production of CLF-1 steel plates.
