正火轧制对Q460钢典型层面强韧性及取向分布的影响

Firstly, Q460 high strength low alloy steel was treated by "normalizing+rolling" and "hot rolling + normalizing", and then the microstructure and micro orientation of different layers of the experimental steel treated by different processes were studied by scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) technique. The results show that the difference of microstructure and texture of typical layer leads to the difference of strength and toughness of the Q460 steel under the two processes. The microstructure of the experimental steel treated by the two processes is a mixed structure of "ferrite + pearlite", but compared with the normalized steel plate, the pearlite interlamellar spacing at 1/4 thickness of the normalized rolled steel plate is obviously larger. Although the pearlite content of the two samples is the same, there are more distortion, dislocation and other defects stored in the normalized rolled steel plate, as a result, the tensile properties of the normalized rolled steel plate are slightly higher than that of the normalized steel plate. The average effective grain sizes at 1/4 and 1/2 thickness of the normalized rolled samples are 7.43 and 9.18 μm, respectively, and the average effective grain sizes at 1/4 and 1/2 thickness of the normalized samples are 6.08 and 6.24 μm, respectively. The difference of grain size is one reason for the difference of impact properties of the samples, and the type and content of texture are another reason for the difference of impact properties.