The morphology and formation of surface and internal crack of 304 stainless steel 1200 mm×2 mm casting strip produced by twin-roll concasting process were tested and analyzed by scanning electron microscope(SEM). Due to adopting high thermal conduction copper mould

the surface and interal cracks with length up to 140 mm and depth 0.33 mm occurred in strip and there was delamination phenomenon in strip scction. The test results showed that the cooling rate of  molten steel in copper mold came to(1～4)×10

3

K/s;because strip strand touched low temperature mold roller

the temperature gradient in solidification was up to 10

5

K/m

the internal stress producad by temperature difference and steess concentration led to crack formation;and the inclusions such as MnS

MnO

Cr₂O₃ are crack initation.