Surface Failure and Durability of Induction-Hardened Sintered Powder Metal Rollers and Gears With Various Hardened Depths

1992 ◽  
Author(s):  
Akira Yoshida ◽  
Yuji Ohue ◽  
Isamu Karasuno
Keyword(s):  
Shear Stress ◽  
Vickers Hardness ◽  
Failure Modes ◽  
Surface Hardness ◽  
Radius Of Curvature ◽  
Powder Metal ◽  
Relative Radius ◽  
Surface Fatigue ◽  
Sintered Powder ◽  
Orthogonal Shear Stress

Abstract In this study, the effect of hardened depth on failure modes and fatigue strengths of induction-hardened sintered powder metal test rollers and spur gears is elucidated also with the effect of relative radius of curvature of the test rollers. These experimental results are discussed by an amplitude of ratio of orthogonal shear stress to Vickers hardness. Failure mode of the test rollers was spelling due to subsurface origin crack with slight micropits and that of the test gears was pitting due to surface origin crack with spall near the pitch point independent of the hardened depth. The depths of spalling cracks agreed almost with the occurring depths of peak amplitude of the ratio of orthogonal shear stress to Vickers hardness. Surface durability of the test rollers increased as the surface hardness increased and the relative radius of curvature decreased almost independent of the hardened depth. Surface fatigue life of the test gears was hardly influenced by the hardened depth.

Surface Failure and Durability of Induction-Hardened Sintered Powder Metal Rollers and Gears with Various Hardened Depths

1994 ◽  
Vol 116 (3) ◽  
pp. 730-737 ◽  
Author(s):  
A. Yoshida ◽  
Y. Ohue ◽  
I. Karasuno
Keyword(s):  
Shear Stress ◽  
Vickers Hardness ◽  
Failure Modes ◽  
Surface Hardness ◽  
Radius Of Curvature ◽  
Powder Metal ◽  
Relative Radius ◽  
Sintered Powder ◽  
Surface Durability ◽  
Orthogonal Shear Stress

In this report, the effect of hardened depth on failure modes and fatigue strengths of induction-hardened sintered powder metal rollers and spur gears was elucidated, including the effect of relative radius of curvature of the rollers. These experimental results were discussed by an amplitude of ratio of orthogonal shear stress to Vickers hardness. Failure mode of the rollers was spalling due to subsurface origin crack with slight micropits and that of the gears was pitting with spall near the pitch point independent of the hardened depth. The depths of spalling cracks agreed almost with the occurring depths of peak amplitude of the ratio of orthogonal shear stress to Vickers hardness. Surface durability of the test rollers increased as the surface hardness increased and the relative radius of curvature decreased. Surface durability of the test rollers and the test gears was hardly influenced by the hardened depth.

Effects of Case Depth and Relative Radius of Curvature on Surface Durability of Case-Hardened Chromium Molybdenum Steel Roller

1981 ◽  
Vol 103 (2) ◽  
pp. 474-481 ◽  
Author(s):  
K. Fujita ◽  
A. Yoshida
Keyword(s):  
Shear Stress ◽  
Vickers Hardness ◽  
Maximum Amplitude ◽  
Case Depth ◽  
Radius Of Curvature ◽  
Steel Roller ◽  
Relative Radius ◽  
Molybdenum Steel ◽  
Surface Durability ◽  
Hardened Chromium

In this report, effects of case depth and relative radius of curvature on surface durability of case-hardened chromium molybdenum steel roller are experimentally clarified. The experimental results are discussed by amplitude of ratio of shear stress to Vickers hardness considering hardness and residual stress distributions of roller. Surface failure mode in this experiment was spalling due to the crack having the point of origin beneath the surface. Depth of spolling crack agreed well with depth of the maximum amplitude of the ratio of orthogonal shear stress to Vickers hardness. Surface durability of the roller tended to increase as the case depth increased, but in the case of too deep case depth it was not so high. And the surface durability tended to decrease as the relative radius of curvature increased.

The Toroid Contact Roller Test as Applied to the Study of Bearing Materials

1962 ◽  
Vol 84 (1) ◽  
pp. 181-189 ◽  
Author(s):  
W. J. Greenert
Keyword(s):  
Heat Treatment ◽  
Shear Stress ◽  
Fatigue Life ◽  
Statistical Evaluation ◽  
Surface Fatigue ◽  
Aisi 52100 ◽  
Bearing Materials ◽  
Contact Surfaces ◽  
Contact Roller ◽  
Orthogonal Shear Stress

An understanding of the basic mechanics and statistical variables of the contact roller test as it is applied to surface fatigue phenomena was obtained. One hundred ninety-four contact rollers of AISI 52100 bearing quality steel were tested to establish dispersion limits. No significant fatigue differences were indicated for heats, bars, or test replications among steels of similar quality, composition, and heat-treatment. A statistical evaluation of results points to the contact roller test as a suitable means for studying significant variables that pertain to both the theoretical and material aspects of antifriction bearings. Stresses in the contact surfaces based on the orthogonal shear-stress theories showed good correlation with fatigue life.

Synthesis and Characterisation of Anodized Powder Metallurgy Mg-Ca Alloy

2018 ◽  
Vol 280 ◽  
pp. 221-225
Author(s):  
C.D. Zuraidawani ◽  
F.W. Norhadira ◽  
Mochd Nazree B. Derman
Keyword(s):  
Powder Metallurgy ◽  
Oxide Film ◽  
Vickers Hardness ◽  
Film Formation ◽  
Surface Hardness ◽  
Powder Metallurgy Method ◽  
Xrd Pattern ◽  
Surface Changes

The Mg-1wt.%Ca alloy was fabricated using powder metallurgy method. The anodizing process were done by using different voltage (5V, 15V, 25V) and concentration of KOH (0.1M, 0.5M, 1.0M). The surface changes on PM Mg/1wt.%Ca resulted by anodizing was analyzed using SEM-EDX and XRD pattern. Meanwhile, surface hardness was measured by micro-Vickers hardness machine. The experiment found different XRD pattern between all non-anodized and anodized samples. The study found that increasing the voltage will increase the hardness while increasing KOH concentration reduced the hardness. The relation of the hardness and oxide film formation can be analyzed using SEM-EDX and XRD pattern. The optimum value for voltage, KOH concentration and hardness are 25V, 0.1M and 27.2 HV. The XRD detect the changes in PM Mg/1wt.% Ca indicates the oxide film formation.

Sign in / Sign up

Export Citation Format

Share Document