Ratcheting Properties of Steel 45 and 42CrMo under High Cyclic Stress

Abstract

Disposable mechanical elements are widely used in many fields such as aerospace and military industries. It is known for their extremely short work time which is quite different from general mechanical elements. The stress level of disposable mechanical elements is much higher than general mechanical elements. In this situation, the traditional fatigue fracture failure will be replaced by fatigue elastic failure used in the design of disposable mechanical elements. The fatigue elastic failure is closely related to the ratcheting properties of materials. Therefore, this paper focuses on the ratcheting properties of typical cyclic softening materials steel 45 and 42 CrMo. The fatigue elastic failure phenomenen of these two materials are shown through the stress control tests.

STRESS ANALYSIS IN CYLINDRICAL SPECIMENS MADE FROM 34CrMo4 USING DIC

“…Heat-treated steel is characterized by mean values of toughness, yield strength and ductility. This material is not susceptible to tempering brittleness, difficult to weld and prone to chilling cracks after hot forming, initiated mainly by indentations and surface defects [14][15][16][17][18]. The chemical composition of the steel is shown in Table 1.…”

Comparative strain analysis of 34CrMo4 steel and Inconel 738LC

“…So, the microstructure could be formed of martensite or transformed martensite. Although no susceptibility to tempering brittleness is manifested, this steel possesses welding difficulties and a tendency to chilling cracking after hot forming, initiated mainly by indentations and surface defects [5][6][7][8].…”