scholarly journals Relation between bending fatigue limit and residual stress in VC coated steels by immersing in a molten borax bath.

1988 ◽  
Vol 37 (418) ◽  
pp. 770-775 ◽  
Author(s):  
Katsushi SARUKI ◽  
Shoji HOTTA ◽  
Hironori FUJITA ◽  
Tohru ARAI
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Bending Fatigue ◽  
Borax Bath

Effect of Pre-Strain and Roller Working on Torsional Fatigue Properties of a Structural Steel

2011 ◽  
Vol 295-297 ◽  
pp. 2227-2230
Author(s):  
Cong Ling Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Work Hardening ◽  
Compressive Residual Stress ◽  
Strain Ratio ◽  
Fatigue Tests ◽  
The Other ◽  
Fatigue Properties ◽  
Torsional Fatigue ◽  
Stress Work

In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

Failure analysis and countermeasures of the SCM435 high-tension bolt of three-step injection mold

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ki-Woo Nam ◽  
Seo-Hyun Yun
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Failure Analysis ◽  
Crack Length ◽  
Fatigue Limit ◽  
Vickers Hardness ◽  
Injection Mold ◽  
Content Type ◽  
Damaged Material ◽  
High Tension

PurposeThe objective of this study was to perform damage analysis of SCM435 high-tension bolts connecting upper and lower parts of a three-stage injection molding machine.Design/methodology/approachDamage material used in this study was a SCM435 high-strength bolt connecting upper and lower molds of a three-stage injection mold. Causes of damage were determined by macroscopic observation. Microstructure observation was done using a metallic microscope, scanning electron microscope (SEM, S-2400, HiTachi, Japan), energy dispersive X-ray spectroscopy (EDS, Kevex Ltd., Sigma) and Vickers hardness tester (HV-114, Mitutoyo). Fatigue limit of the damaged material was evaluated using equivalent crack length.FindingsBolts were fractured by cyclic bending stress in the observation of ratchet marks and beach marks. The damaged specimen showed an acicular microstructure. Impurity was observed. Chromium carbide was observed near the crack origin. Both shape parameters of the Vickers hardness were similar. However, the scale parameter of the damaged specimen was about smaller than that of the as-received specimen. Much degradation occurred in the damaged specimen. Bolts should undergo accurate heat treatment to prevent the formation of chromium carbide. They must prevent the action of dynamic stresses. Bolts need accurate tightening and accuracy of heat treatment. Screws require compression residual stress due to peening.Originality/valueThis study conducted failure analysis of damaged SCM435 bolts connecting upper and lower parts of the three-stage injection mold. Fatigue limit of the damaged material was evaluated using equivalent crack length. In order to control this fracture, accurate tightening of bolts, accuracy of heat treatment and screws are required for compression residual stress due to peening.

Reverse bending fatigue of shot peened 7075-T651 aluminium alloy: The role of residual stress relaxation

2009 ◽  
Vol 31 (8-9) ◽  
pp. 1225-1236 ◽  
Author(s):  
M. Benedetti ◽  
V. Fontanari ◽  
P. Scardi ◽  
C.L.A. Ricardo ◽  
M. Bandini
Keyword(s):  
Residual Stress ◽  
Stress Relaxation ◽  
Aluminium Alloy ◽  
Bending Fatigue ◽  
Residual Stress Relaxation

2210 Residual Stress and Bending Fatigue Strength of Case-Carburized Thin-Rimmed Spur Gears with Web Arrangement

2006 ◽  
Vol 2006.6 (0) ◽  
pp. 217-220
Author(s):  
Kouitsu MIYACHIKA ◽  
Wei-Dong XUE ◽  
Kengo NOJIMA ◽  
Tomoya YOSHIKAWA ◽  
Hidefumi MADA ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Spur Gears ◽  
Bending Fatigue ◽  
Bending Fatigue Strength

Effects of Residual Stresses on the High Cycle Fatigue Behavior of Ti-6Al-4V

2010 ◽  
Author(s):  
Yu-Jia Li ◽  
Fu-Zhen Xuan ◽  
Zheng-Dong Wang ◽  
Shan-Tung Tu
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Stress Ratio ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Manufacturing Techniques ◽  
Stress Ratios ◽  
Effect Of Surface

Axial force-controlled fatigue tests are conducted at various stress ratios (R) on Ti-6Al-4V specimens prepared by two different manufacturing techniques (hard turning plus polishing with and without vacuum stress relieve anneal carried out after polishing). Residual stress is measured by using X-ray diffraction. Results indicate that the surface compressive residual stress lead to an increase of fatigue limit at a given life and stress ratio. This effect decreases with increasing stress ratio R. At R = 0.6, the effect of surface residual stress on fatigue limit fades away. In addition, the location of crack initiation shifts from surface to interior when the stress ratio changes from −1 to 0.6.

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