Abstract：In order to find out the cause of surface cracks for the same batches slab, surface crack on micro-alloyed steel plate produced by direct hot charging process was investigated by means of metallographic analysis, scanning electron microscopy, energy spectrometer analysis and transmission electron microscopy, and compared with crack-free plate produced by cool charging process. The results show that the main factors of surface crack on micro-alloyed steel plate produced by direct hot charging process are the segregation of low melting point elements such as Cu, As in slab’s cooling or heating process. Compared with hot-rolled plates produced by hot charging, the grain size of cold charged rolled plate about 10μm in diameter, while the grain size of hot-rolled plates by hot charging are large and uneven. Precipitates of hot plate are between 15 -25nm in size, the crack source are more than the matrix and a large amount of fine Nb(CN) precipitate at the boundary of the austenite grains, which decreases the strength of the grain boundary sharply.
刘志明，张炯明，罗衍昭. 热装热轧微合金钢板表面裂纹分析[J]. 钢铁, 2012, 47(2): 67-71.
LIU Zhi-ming,ZHANG Jiong-ming,LUO Yan-zhao. Investigation of Surface Crack on Micro-Alloyed Steel Plate by DHCR. Iron and Steel, 2012, 47(2): 67-71.
2012, Vol. 47 
