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针对连铸-热轧区段的工艺技术界面,在传热研究的基础上通过热模拟实验研究了典型大板坯生产流程连铸、辊道输送、堆冷、加热等单元内X80钢中碳氮化物的析出与固溶行为.结果表明,在连铸和输送过程中,Ti(C,N),(Ti,Nb)(C,N)和NbC先后析出,加热结束尚有少量(Ti,Nb)(C,N)未完全固溶;输送过程中不同冷却速率对碳氮化物的析出影响显著,以6.0℃/min辊道冷却至750或600℃,析出的碳氮化物分布密度较大,平均当量直径较小,部分碳氮化物沿奥氏体晶界分布,碳氮化物形成元素在钢中呈过饱和状态;以0.3℃/min堆冷却至400℃,碳氮化物充分析出,粒子的分布密度较小,平均当量直径较大;加热过程的热履历影响铸坯中碳氮化物的行为,但对加热结束后碳氮化物的存在状态无显著影响;冷却速率是导致碳氮化物沿奥氏体晶界析出的根本原因.
Aiming at the process technology interface of continuous casting and hot rolling section, based on the research of heat transfer, the simulation experiment of typical large slab production process, such as continuous casting, roller conveyor, stack cooling, heating and so on, (Ti, Nb) (C, N) and NbC were precipitated in the continuous casting and conveying process, and a small amount of Ti, Nb) (C, N) did not completely dissolve. The different cooling rates during the transportation had a significant effect on the precipitation of carbonitrides. When the cooling temperature was 6.0 ℃ / min, the distribution density of carbonitride was large , The average equivalent diameter is small, part of the carbonitride along the austenite grain boundary distribution, carbonitride forming elements in the steel was supersaturated; with 0.3 ℃ / min heap cooling to 400 ℃, carbonitride precipitation, particles And the average equivalent diameter is larger. The thermal history of the heating process affects the behavior of carbonitrides in the slab, but has no significant effect on the existence of carbonitrides after the heating. The cooling rate is a function of the carbonitride Austenite grain boundary precipitation of the root causes.