Correct Answer - Option 2 : Electroplating of the surface
Explanation:
Fatigue strength is the highest stress that a material can withstand for a given number of cycles without breaking.
The process which improves fatigue strength are as follows:
Polishing of the surface:
- The surface of the rotating beam specimen is polished to mirror the finish. The final polishing is carried out in the axial direction to smooth out any circumferential scratches. Scratches present increases the stress concentrations and reduces the fatigue strength of a specimen. Thus, polishing improves fatigue strength.
Shot peening:
- Shot peening is a cold work process used to impart compressive residual stresses on to the surface of a component, which results in modified mechanical properties.
- The shot peening process is used to add strength and reduce the stress profile of components.
Cold rolling:
- Cold rolling is a process by which steel is strengthened by changing its shape below its recrystallization temperature.
- It strengthens a component due to strain hardening and also improves surface finish which increases and improves fatigue strength.
Electroplating of the surface:
Electroplating increases the tensile strength of a component.
