Cementite Distribution in Steel 



145 



Figure 2b, shows the appearance of the specimen containing the 

 high silicon insert after it had been heated at 950 °C. for three hours. 

 There is a narrow but well defined band of cementite about the insert. 



Fig. 2. a, Cementite segregated about high phosphorus insert in hyper-eutectoid 

 steel ; b, cementite segregated about high silicon insert in hyper-eutectoid steel ; c, 

 cementite segregated about alumel insert in hyper-eutectoid steel ; d, cementite segregated 

 about copel insert in hyper-eutectoid steel, a and b etched with nitric acid, c and d 

 with sodium picrate. x SO. 



The width of this zone corresponds to tiie depth to which the material 

 from the insert had penetrated into the surrounding steel. This diffused 

 material was probable iron silicide. 



