Describe 2 material properties that are affected by Grain Si

Describe 2 material properties that are affected by Grain Size in steels, and how increasing or decreasing the grain size affects that property.

Solution

1. Grain size affects the yield strength of the steel , yield strength of steel increses proportional to the squareroot of grain size, this theory is based on the hall petch equation

according to hell petch equation , yield strength=stress+k_yd^(-0.5) ; where k_y   is hall petch slope and \"d\" is mean grain size.

2. grain size affects the fatigue strength of steel.if grain size of steel is small fatigue strength will be high vice versa.