Hence precise control of the heat treatment process to obtain martensite layers, least delta ferrite, and retained austenite is very important [6].
[8] on Cr-martensitic steels were carried out to find the effect of delta ferrite and dendritic carbides precipitated on the delta ferrite boundaries which caused the drop in impact energy.
Influence of delta ferrite and dendritic carbides on the impact and tensile properties of a martensitic chromium steel, Journal of Nuclear Materials 258-263: 1336-1339.