奥氏体碳浓度不均匀在球化退火中作用机理的研究

Study on the Mechanism of the Austenite of Inhomogenous Carbon Concentration in the Spheroidizing Annealing

本文研究了球化加热时奥氏体内碳浓度均匀与否在球化组织形成及长大过程中的作用，认为球化加热时不仅需要保留尽可能多的剩余碳化物颗粒，还要促使奥氏体过冷分解时另一相（α）不受剩余碳化物的引领，而在远离碳化物的奥氏体深处单独形核，从而抑制共析体核心的形成，并使两个相各自呈球状独立长大，最终获得粒状珠光体（Ｐｓ）。奥氏体内碳浓度的不均匀恰好起到这种作用，它是加速球化过程获得Ｐｓ组织的有效措施，在生产中应用能使球化的加热时间缩短约８０％。

In this paper the effect of the austenite of inhomogenous carbon concentration on spheroidal grains nucleation and growth during spheroidizing has been studied. The results show that during spheriodizing, not only need remaining the residual particle carbides as more as passible, but also need nucleating individually the ferrite (α) phase in austenite (γ) which is far away from carbides, thus restraining the nucleation of eutectoid, and both α and carbides grow into spheroidal grains respectively, the spheroidal pearlite (P s) has been obtained at last. The γ of inhomogenous carbon concentration is effective measure to obtain P s structure and to accelarate spheroidizing process. The heat of the spheroidizing in industry has been reduced by about eighty percent.