Preliminary Metallographic Studies of Ball Fatigue Under Rolling-contact Conditions PDF Download
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Author: H. Robert Bear
Publisher:
ISBN:
Category : Ball-bearings
Languages : en
Pages : 48
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Book Description
The metallurgical results produced on balls tested in the rolling-contact fatigue spin rig were studied by metallographic examination. Origin and progression of fatigue failures were observed. These evaluations were made on SAE 52100 and AISI M-1 balls fatigue tested at room temperature (80 F) and 200 to 250 F. Most failures originated subsurface in shear; inclusions, structure changes, and directionalism adversely affected ball fatigue life. Structures in the maximum-shear-stress region of the balls of both materials were stable at room temperature and unstable at 200 to 250 F. Failures were of the same type as those found in full-scale bearings.
Author: H. Robert Bear
Publisher:
ISBN:
Category : Ball-bearings
Languages : en
Pages : 48
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Book Description
The metallurgical results produced on balls tested in the rolling-contact fatigue spin rig were studied by metallographic examination. Origin and progression of fatigue failures were observed. These evaluations were made on SAE 52100 and AISI M-1 balls fatigue tested at room temperature (80 F) and 200 to 250 F. Most failures originated subsurface in shear; inclusions, structure changes, and directionalism adversely affected ball fatigue life. Structures in the maximum-shear-stress region of the balls of both materials were stable at room temperature and unstable at 200 to 250 F. Failures were of the same type as those found in full-scale bearings.
Author: United States. National Advisory Committee for Aeronautics
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1030
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Book Description
Author: Robert H. Butler
Publisher:
ISBN:
Category : Ball-bearings
Languages : en
Pages : 30
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Book Description
The rolling-contact fatigue spin rig was used to test groups of SAE 52100 9.16-inch-diameter balls lubricated with a mineral oil at 600,000-, 675,000-, and 750,000-psi maximum Hertz stress. Cylinders of AISI M-1 vacuum and commercial melts and MV-1 (AISI M-50) were used as race specimens. Stress-life exponents produced agree closely with values accepted in industry. The type of failure obtained in the spin rig was similar to the subsurface fatigue spells found in bearings.
Author: J. J. C. Hoo
Publisher: ASTM International
ISBN: 9780803107120
Category : Technology & Engineering
Languages : en
Pages : 442
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Book Description
Author: Erwin V. Zaretsky
Publisher:
ISBN:
Category : Ball-bearings
Languages : en
Pages : 18
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Book Description
Residual stress measurements were made in the zone of resolved shearing stress on five SAE 52100 upper test ball specimens with an average Rockwell C hardness of 63.2. These upper test ball specimens were run against lower test balls of nominal Rockwell C hardnesses of 60, 62, 63, 65, and 66 until either ft conditions included an or both components failed because of fatigue. Test conditions included an average race temperature of 150 F, a maximum (Hertz) compressive stress of 800,000 psi, and a highly purified naphthenic mineral oil lubricant. Fatigue lives of the upper test balls were compared with measured residual stresses in the subsurface zone of resolved shearing stress. The compressive residual stress induced in the upper test ball during running is a function of delta H, the hardness of the lower test balls minus the upper test ball hardness An interrelation is indicated among differences in com- ponent hardness, induced compressive residual stress, and fatigue life. Measured values of compressive residual stress within the zone of resolved maximum shearing stress ranged from 178,000 and 294,000 psi. The apparent maximum residual stress occurs above where delta H = 0.
Author: Pei Moo Ku
Publisher:
ISBN:
Category : Lubrication and lubricants
Languages : en
Pages : 602
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Book Description
Lubrication, wear, and design aspects of rolling contact bearings.
Author: P. M.. Ku
Publisher:
ISBN:
Category :
Languages : en
Pages : 616
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Book Description
Author: Thomas L. Carter
Publisher:
ISBN:
Category : Ball-bearings
Languages : en
Pages : 58
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Book Description
Author: J. J. C. Hoo
Publisher: ASTM International
ISBN: 9780803102897
Category : Technology & Engineering
Languages : en
Pages : 232
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Book Description
Author: William A. Newsom
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 714
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Book Description
An investigation has been made to determine the effect of propeller location and flap deflection on the lift, drag, and pitching-moment characteristics of a wing-propeller combination over an angle-of-attack range from 0 to 80 degrees. The model had four propellers, the slipstream from which covered practically the entire span of the wing. The wing had a 30-percent-chord slotted flap and an 8.5-percent-chord slat. Data were obtained for flap deflections of 0, 20, 40, and 60 degrees with the slat off and on. For one propeller position the power input to the model was measured and tuft studies of the flow on the wing were made. The data are analyzed to assess the feasibility, from consideration of stability and control, of a tilting-wing vertical-take-off-and-landing airplane with the wing pivoted behind the primary wing structure to provide a desirable structural configuration. The main object of the investigation was to determine whether advantage might be taken of the forward shift of the center of gravity of the airplane, as the wing is tilted from an angle of attack of 90 to 0 degrees, to minimize the change in trim pitching moment throughout the transition speed range for such a configuration. The results indicate that with proper propeller position and programming of flap deflection, it is possible to design a configuration of this type in which essentially no change in trim is required throughout the transition from hovering to normal unstalled forward flight.
