【摘要】 以不同成份的低碳Fe-Mn-B系钢及其它几种低碳合金钢12MoVWBSiRE、18Cr2Ni4W。12GrMoV等,研究了粒状贝氏体的形态及精细结构,并对相变机理作了初步探讨。本文提出,人们通常认为粒状贝氏体中,客观上包括二类,我们暂称一类是"块型粒状贝氏体,另一类是"条型粒状贝氏体,两者可单独或同时存在。这两类粒状贝氏体具有基本的共同点,但必须指出,两者在金相形貌、精细结构、浮凸效应及转变机制上均有差别。粒状贝氏体中小岛的组织可以是M+残γ或M+B+γ或其它亚稳组织,这取决于相变时奥氏体的成份及冷速。本文闸述了粒状贝氏体中小岛的形貌、尺寸、数量及粒状贝氏体类型分别受奥氏体化温度(或晶粒度)、相变时冷速及奥氏体成份的影响。更多还原

【Abstract】 The morphology and fine structure of granular bainite are researched with different composition of low C-Fe-Mn-B system bainitic steel and other alloy system steels. Furthermore, its trasformation mechanism is now under discussion. The granular bainite commonly includes two types: one is massive granular bainite as we call it temporarily, the other is lath granular bainite. Both of them may exist simultaneously or independently and possess common basic characteristics. But, it must be pointed out that there are difference between them on metallographic morphology, fine structure, relief effect and transformation mechanism. The structure of inside islands of granular bainite may be M+γ (retained) or M+B+γ (retained) or other metastable structure, which is determined by the composition of austenite and cooling rate. The metallographic morphology, size and quantity of islands, and type of granular bainite are effected by the composition of austenite, austenitizing temperature and cooling rate during transformation. The effected regularity is described in this paper too.更多还原