Introduction 介绍The precipitation and growth of aluminum nitride in low carbon Al-killed steel is one of the fundamental metallurgical processes that affect the final microstructure and properties (Ref 1) 氮化铝的析出和生长是低碳铝镇静钢最基本的冶金过程，它影响最终的金相组织和性能。The microstructure of steel evolves during hot rolling and cooling 热轧及冷却过程中钢的金相组织的演变。The various important factors， which affect the microstructure of the steel， are dissolution of AlN during heating and soaking， strain-induced precipitation of AlN during hot rolling， interpass recrystallization， austenite grain coarsening， finish rolling temperature (FRT)， and cooling of the 影响钢金相组织的各种重要因素是：加热及均热过程中氮化铝的溶解、氮化铝在热轧过程中的应变诱导析出、层间再结晶、奥氏体晶粒粗化、扎制结束温度和钢带的冷却。 The evolution of grain size has been shown (Ref 2) to be different in low-carbon steel than that of other 低碳钢晶粒大小的演变与其它钢不同。 Thin slab casting and rolling (TSCR) of low-carbon steel has some distinguished characteristics， such as finer 连铸连轧低碳铝镇静钢拥有卓越的性能，例如出色的金相组织。 Much faster cooling rate and rapid solidification (Ref 3) in association with liquid core reduction result in finer grains in thin slabs as compared to conventional thick 与传统的厚板相比，薄板冷却快速、凝固快速和液核少。 This initial austenite grain size of slab plays an important role for controlling the final microstructure of the 这个初始奥氏体晶粒尺寸对最终钢带的金相组织控制有重要作用。 During casting， some aluminum nitrides also precipitate in thin slabs before entry into the tunnel furnace and may not dissolve during heating and soaking (Ref 4) at 1150°C for about 22 在铸造期间，有一些氮化铝在进入隧道炉之前在薄板里析出，析出的氧化铝在加热及均热（1150°C ，22 分钟）期间可能不会分解。 These fine precipitates restrain the growth of recrystallized austenite grains， which significantly affect the final 这些细小的析出相抑制了再结晶奥氏体晶粒的增长，从而影响了最终金相组织。Further， during hot rolling process some amount of fine AlN precipitates at different stages because of strain and decrease in 而且在热轧过程期间的应变及降温也会使氮化铝析出。 These precipitates inhibit austenite grain growth by pinning grain boundaries leading to refining of austenite and hence ferrite 这些析出的氮化铝抑通过限定边界来制奥氏体的增长，从而细化奥氏体晶粒和和铁素体晶粒。
