硅和磷对铁素体可锻铸铁回火脆性的影响

Effect of Silicon and Phosphorous on the Temper Brittleness of Ferritic Malleable Cast Ieon

本文对不同的硅、磷含量及不同的热处理条件下的铁素体可锻铸铁试样,测试了其冲击韧性和显微硬度,根据其变化规律阐明了硅和磷对铁素体可锻铁回火脆性的影响.同时利用扫描电镜、电子探针等显微分析方法研究了具有回火脆性试样的显微组织,以及因冷却速度变化引起硅、磷的晶界偏析与回火脆性的关系;并对试验过程中发现具有回火脆性试样中部分铁素体晶界变为“双晶界”这一特殊现象,作了比较深入的探讨.

In this paper,the Charpy impact and microhardness have been measured of ferritic malleable cast iron samples with different content of silicon and phosphorous and different heat treatment.According to its change regulation,the effect of silicon and phosphorous on the temper brittleness is stated.At the same time,the microstru- cture of the embrittled samples has been studied with the aid of SEM and EMPA, and the relationship between grain-boundary segregation of silicon,phosphrous and temper brittleness caused by cooling rate change has been analysed.The phenomenon in the course of experiments is discovered and analysed in details,in which the str- ucture of ferritic grain boundaries is changed,and some boundaries are turned into dualgrain of embrittled samples.