Effect of surface plastic deformation on the inelastic characteristics and fatigue limit of steels 20 and 14Kh17N2 with cyclic torsion

1989 ◽  
Vol 21 (5) ◽  
pp. 687-690 ◽  
Author(s):  
S. M. Lyalikov
Keyword(s):  
Plastic Deformation ◽  
Fatigue Limit ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Cyclic Torsion ◽  
Effect Of Surface

Effect of surface plastic deformation on the development of fatigue cracks

1974 ◽  
Vol 6 (1) ◽  
pp. 93-95
Author(s):  
M. A. Balter ◽  
L. Ya. Gol'dshtein ◽  
A. A. Chernyakova ◽  
A. I. Reznik
Keyword(s):  
Plastic Deformation ◽  
Fatigue Cracks ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Effect Of Surface

Influence of structure and properties of surface layer on fatigue durability of hardened steels strengthened by combined electromechanical treatment

2019 ◽  
Vol 62 (6) ◽  
pp. 438-450
Author(s):  
V. P. Bagmutov ◽  
N. G. Dudkina ◽  
I. N. Zakharov ◽  
M. D. Romanenk ◽  
V. V. Chekunov
Keyword(s):  
Plastic Deformation ◽  
Fatigue Limit ◽  
Surface Hardening ◽  
Strain State ◽  
Surface Plastic Deformation ◽  
Carbon Steels ◽  
Surface Plastic ◽  
Surface Microhardness ◽  
Near Surface ◽  
Surface Metal

Using the example of hardened carbon steels (steel 45, U8), the effect of combination of various surface hardening technologies is considered (using electromechanical processing, surface plastic deformation, non-abrasive ultrasonic finishing and their combination) on changes in structural state and surface microhardness, cyclic durability of hardened specimens and fatigue failure mechanisms. The studies were carried out by the methods of optical and scanning electron microscopy and by microhardness and fatigue tests. It is shown that for the investigated steels in quenched state, a high-speed pulsed thermo-deformation effect during electromechanical processing is accompanied by an increase in the surface microhardness (by more than 50 %) and decrease in the fatigue limit (by 20 – 30 %). Such a change in properties is associated with formation in the surface layer of substantially non-equilibrium, inhomogeneous in chemical composition, ultradispersed phases with increased hardness. At the same time, in the near-surface metal volumes tempering processes of the hardened structure proceed with the formation of softening zones and tensile residual stresses, accompanied by a decrease in the microhardness in these zones and the fatigue limit of the specimens. Such effects reduce some of the materials performance characteristics during surface hardening. The ways to improve the properties of such products due to additional technological operations require further studies. Combined surface hardening (based on electromechanical processing, surface plastic deformation and non-abrasive ultrasonic finishing) of carbon steels allows, due to variations in the intensity of temperature and deformation effects, to purposefully change the structural-phase composition and stress-strain state of the surface and near-surface metal layers. As a result, it becomes possible to form a balanced complex of strength and fatigue characteristics of the samples, depending on the preliminary heat treatment of steel. The operations of surface plastic deformation and non-abrasive ultrasonic finishing after electromechanical hardening, due to intensive plastic deformation provide smoothing of the surface and healing of near-surface defects and allow correction of stress-strain state of the processed metal. It provides an increase in microhardness in the tempering zone by 20 – 25 % and the fatigue limit of the samples by 25 – 30 %. 

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