Impact of Ball Burnished Regular Reliefs on Fatigue Life of AISI 304 and 316L Austenitic Stainless Steels

Abstract

The present work describes an experimental investigation of the fatigue durability of AISI 304 and AISI 316L austenitic stainless steels, which have regular reliefs (RR) of the IV-th type, formed by ball burnishing (BB) on flat surfaces, using a computer numerical control (CNC) milling center. The methodology and the equipment used for obtaining regular reliefs, along with a vibration-induced fatigue test setup, are presented and described. The results from the BB process and the fatigue life experiments of the tested austenitic stainless steels are gathered, using the approach of factorial design experiments. It was found that the presence of RR of the IV-th type do not worsen the fatigue strength of the studied steels. The Pareto, t-test and Bayesian rule techniques are used to determine the main effects and the interactions of significance between ball burnishing regime parameters. A stochastic model is derived and is used to find when the probability of obtaining the maximum fatigue life of parts made of AISI 304 or 316L reaches its maximum value. It was found that when the deforming force, the amplitude of the sinewaves and their wavenumber are set at high values, and the feed rate is set at its low value, the probability to reach maximum fatigue life for the parts made of AISI 304 or 316L is equal to 97%.

Research of the Ball Burnishing Impact over Cold-Rolled Sheets of AISI 304 Steel Fatigue Life Considering Their Anisotropy

“…This leads to an increase in the unfolded length of the toolpath in comparison with conventional BB operations. Some examples of such mathematically calculated toolpaths, used in BB operations, on the CNC machines are given in [ 28 , 33 ]. The task to optimize the BB process carried out using CNC equipment to minimize the unfolded toolpath length is relevant in the context of the contemporary requirements of production processes.…”

“…Dzierwa and Markopoulos [ 20 ], who also have studied the surface roughness and residual stresses of the 42CrMo4 steel, reached similar conclusions about the positive effects of the BB process. A large amount of published works [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] show that the application of different finishing methods, related to plastic deformation in the surface layer of the different materials, can significantly increase the surface integrity and fatigue life of the parts, subjected to the cyclic load.…”

Studies on the Microstructural Evolution and Mechanical Properties of Superalloy Inconel 718 Induced by Low Plasticity Burnishing Coupled with Turning

“…On the other hand, mechanical surface modification technologies are commonly performed to introduce beneficial compressive residual stresses and surface strengthening for fatigue life improvement, including shot peening, low plasticity burnishing and laser shock peening [ 8 , 9 ]. Shot peening (SP) typically produces a high degree of cold-work (up to 30–40%) and compressive residual stress.…”

Influence of Some Microchanges Generated by Different Processing Methods on Selected Tribological Characteristics

“…The above information, and the information included in other works [20][21][22][23][24][25], refer to changes in some operating properties when a surface layer with a thickness of, at most, several hundred micrometers is affected by the processing methods by which the analyzed surfaces were made.…”