Shot Peening Of Nitrided Layer

Author:  A. Nakonieczny, G. Monka, I. Pokorska
Source:  Conf Proc: ICSP-10 Tokyo, Japan 2008
Doc ID:  2008059
Year of Publication:  2008
Abstract:  
ABSTRACT Shot-peening is a method widely used in industrial practice in order to enhance service properties of machine components. Commonly known are such advantages derived from this dynamic surface cold working, i.e. shot-peening, as: increase of fatigue strength, contact fatigue, resistance to corrosion fatigue and to stress corrosion. The utilization of shot-peening to the enhancement of nitrided layers is the object of increased interest of researchers. The aim of this project was to determine the effect of a 2-step nitriding and shot-peening treatment on the mechanical properties of 40HM (AISI4140) grade steel. A new approach to the nitriding process was taken, enabling the formation of nitrided cases free of the iron nitride layers at the surface. The article contains the results of structural investigations, hardness measurements, measurements of residual stresses, rotational bending fatigue, as well as contact fatigue. KEY WORDS Shot-peening, nitrided layer, residual stresses, pitting, fatigue strength