Analysis of different heat treated materials for fatigue failure

Abstract

Numerous engineering machines and mechanical components are subjected to fluctuating stresses taking place at relatively huge frequencies and failure is commenced to occur under this condition. This is due to ‘fatigue failure’. Fatigue is an action in which the material cracks or fails resulting in cyclic (repeated) stresses applied below the ultimate strength of the material. The applied stresses may be axial, flexural or torsional in nature. In Automobile field, the rotating elements are always subjected to constant or variable loading which is nothing but fatigue. Fatigue failure of various types is key concern in increasing reliability of products. Therefore, to increase fatigue life, effect of heat treatment on fatigue life and fatigue strength need to be studied for better designing of mechanical system.This innovative research scrutinized the effect of heat treatment for fatigue behavior of different materials. The present study shows the comparative study of fatigue testing between non-heat treated & heat treated specimens of En19 & En31 for their fatigue behavior. Specimens were tested under 40, 50, 55, 60, 65, 70, 75 kg on the fatigue testing machine. The counts of cycles leading to failure were listed as well as evaluated using S-N diagram. Heat treated En19 specimens delivered more fatigue life than non-heat treated specimens and non-heat treated En31 specimens shown better fatigue life as compared to heat treated specimens due to its increased brittleness after heat treatment and high material hardness & strength. The stress–number of revolution relationships of these specimens have been addressed in detail and the outcomes of the study will be highly useful for automobile applications.