Question

Electrochemically machined surfaces have high residual stress and reduced fatigue strength insignificant residual stress and improved fatigue strength high residual stresses and improved fatigue strength insignificant residual stress and reduced fatigue strength

Answer 1

Residual stress is the type of stress which remains after removing the original cause or source of that stress.

On the other hand;

Fatigue stress is the type of stress which is caused by the repeated application of the stress on the solid material.

Electrochemical coating metal is more durable than the normal raw metal.

This kind of metals have a insignificant residual stress and a reduced fatigue stress.