关键词: 连铸-热轧区段, 界面, 碳氮化物, 析出, 固溶

Abstract: As for the techno-interface of continuous casting-hot rolling region, the precipitation and dissolution of carbonitrides in X80 steel were studied during continuous casting, roller conveying, stack cooling and heating units in typical slab process flow by hot simulation experiment based on the study of heat transfer. The results showed that Ti(C, N), (Ti, Nb)(C, N) and NbC were precipitated in turn in continuous casting and conveying. A few (Ti, Nb)(C, N) particles were not dissolute totally after heating. The precipitation of carbonitrides was effected significant by cooling rate in conveying. When slab was conveyed at 6.0℃/min rate and then cooled down to 750 or 600℃, the distributing density of carbonitride particles was higher, and their average equivalent diameter smaller, some carbonitride particles were distributed along the austenitic grain boundaries and the elements related to the carbonitride particles were supersaturated. When slab was conveyed at 0.3℃/min rate and then cooled down to 400℃, the distributing density of carbonitride particles was lower, and their average equivalent diameter bigger, the carbonitride particles precipitated fully. The behavior of carbonitrides in slab was affected by thermal course in heating. The status of carbonitrides was affected insignificant by thermal course after heating. The basic reason of carbonitride particles distributed along the austenitic grain boundaries was cooling rate.

Key words: continuous casting-hot rolling region, interface, carbonitride, precipitation, dissolution