Author: Paul F. Brown Publisher: ISBN: Category : Ball-bearings Languages : en Pages : 76
Book Description
Rolling element fatigue life testers, as well as full-scale bearing testers, were used to develop a highly rolling contact fatigue resistant powder processed material (P/M) for use in aircraft turbine engine bearings. Ball and rod elemental tests were conducted, for screening purposes, on three P/M alloys; M-50, T-15 and CRB-7. The best results were realized with the P/M CRB-7 material, a 14 percent chrome corrosion resistant alloy, which demonstrated a B10 life almost twice that of the baseline, conventionally processed VIM-VAR M-50. Twenty full-scale 140 mm ball bearings were subsequently fabricated from P/M CRB-7 alloy. The B10 life realized with these bearings was equivalent to that expected from these same bearings had they been made from conventional VIM-VAR M-50 material. This good result was achieved in spite of an inner ring land wear problem which was alleviated by plating the lands with hard nickel. (Author).
Author: GA. Bogardus Publisher: ISBN: Category : B10 life test Languages : en Pages : 19
Book Description
Two different types of rolling element fatigue testers and a full-scale bearing tester were used in a program aimed at developing a highly fatigue-resistant powder-processed material (P/M) for use in turbine engine bearings. The testers were the single-ball machine evaluating 0.0238-m (15/16-in.)-diameter balls, a rolling contact fatigue machine evaluating 0.00953-m ( 3/8 in.) rods, and a full-scale bearing rig evaluating 140-mm-bore, 0.0238-m (15/16 in.)-diameter ball, angular contact thrust bearings.
Author: P. F. Brown Publisher: ISBN: Category : Languages : en Pages : 90
Book Description
Work under this contract has demonstrated that powder processed bearing steels can be prepared to cleanliness standards consistent with the quality attainable in conventionally vacuum melted bearing steels, and that these alloys can be heat treated and processed into balls of aircraft quality. Rolling contact fatigue testing of three powder processed alloys in laboratory test devices has been completed and results revealed that an experimental alloy, EX00007, essentially a stainless steel composition, exhibited a fatigue life that was 2.2 times greater than that obtained in tests of powder processed M-50 alloy and 1.8 times the life observed for similar tests of VIM-VAR M-50 steel. On the basis of this performance, a recommendation has been made that a sufficient quantity of powder processed EX00007 alloy be procured for fabrication into aircraft gas turbine mainshaft bearings for subsequent endurance testing. (Author).
Author: Edgar Streit Publisher: ISBN: Category : Bearing repair Languages : en Pages : 13
Book Description
Refurbishment of aerospace gas turbine engine bearings is a well established process regularly used to ensure asset availability. Repairs typically follow four well established basic levels. Level one generally requires detailed inspection in accordance with agreed criteria. Level two commonly involves replacement of rolling elements, refinishing of raceway surfaces and re-plating of bearing cages as appropriate. Level three involves the use of raceway grinding in the event that standard honing is insufficient to achieve required product quality. Level four is reserved for cases where one of the bearing rings is replaced. Results from detailed study of product following completion of full scale testing, repair per levels two and four, and continued testing is presented herein. Results demonstrate the absence of subsurface fatigue propagation. Test results conclude the commonly recognized acceptability of the repair methods noted and further support previously published theories regarding infinite fatigue theory. Reference to previously published findings describing expected symptoms of subsurface fatigue propagation are reviewed to support findings.
Author: David MacLeish. Smith Publisher: Springer Science & Business Media ISBN: 1475756232 Category : Science Languages : en Pages : 179
Book Description
This book deals with the functioning of hydrodynamic journal bearings in turbomachinery. It makes particular reference to large turbine generator and marine propulsion plant. Journal-bearing design in this field has been based mainly on experience supplemented by full-scale experimental test. Development is becoming influenced to an increasing extent by research and analysis. Particular attention is given in this book to correlation of research and analytical work with the observed operating characteristics of journal bearings. The physical phenomena in bearings are complicated, and analysis is rendered convenient only by making simplifying assumptions. The engineer must know which assumptions are serviceable and in what operating conditions they may be applied. Current British and European practice in journal bearings is illus trated. An examination is made of steady running characteristics, as predicted by theory and as established by test. Some account is given of the dynamic characteristics of journal bearings and of their in fluence in machine vibration. Service experience of journal bearings is reviewed, and reference is made to possible future trends in develop ment. The book is the outcome of work on turbine plant with Metropolitan Vickers and its successor Associated Electrical Industries. The A.E.!. and English Electric activities in this field have recently been incor porated in English Electric-A.E.!. Turbine-Generators Ltd. The author expresses his gratitude to the Company for permission to publish the results. He thanks the English Electric Co. Ltd., C. A.
Author: National Aeronautics and Space Administration (NASA) Publisher: Createspace Independent Publishing Platform ISBN: 9781722947989 Category : Languages : en Pages : 118
Book Description
The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC. Moracz, D. J. and Shipley, R. J. and Moxson, V. S. and Killman, R. J. and Munson, H. E. Unspecified Center BALL BEARINGS; BEARING ALLOYS; FABRICATION; POWDER METALLURGY; SPACE SHUTTLE MAIN ENGINE; TURBINE PUMPS; CORROSION RESISTANCE; FATIGUE LIFE; FRACTURE STRENGTH; STRESS CORROSION CRACKING; WEAR RESISTANCE...
Author: Stanley Wallerstein Publisher: ISBN: Category : Bearings (Machinery) Languages : en Pages : 140
Book Description
The feasibility of adapting a powder lubrication system for the lubrication of the main shaft bearings of an unfired J-69 gas turbine engine was established, in lieu of the oil lubrication system used in the standard engine. Ball and roller bearings have been successfully lubricated with powder- lubrication in a J-69 unfired gas turbine engine. Ball bearings have been successfully operated for periods of 35 hours with powder lubricants. Thrust load tests to 500 pounds at 8000 rpm were conducted. Testing with a 100 pound thrust load to 20,000 rpm with heated (bleed air temperature) carrier air was successfully performed on two different bearing designs. Both bearings were deep groove, split inner design with a one piece outer ring guided retainer made of silverplated AMS6415 steel; one bearing had inner and outer races and balls of M-50 vacuum melt tool steel; the other the inner and outer races and balls of 440CM modified corrosion resistant steel. Roller bearings have performed successfully through a speed range of 8,000 to 20,000 rpm at stabilized operating temperatures of 515F, simulating estimated operating conditions. The bearing had inner ring guided rollers and an outer ring guided retainer. Rings and rollers were of M-50 vacuum melt tool steel and the retainer was Monel S. The lubricant used for all the evaluations was a powder mixture consisting of five parts of micronized Acheson No. 38 graphite plus one part of laboratory-grade cadmium oxide entrained in an air carrier. The optimum lubricant powder flow for ball bearing operation under thrust loaded conditions is about 0.015 grams per minute.
Author: Paul F. Brown
Author: GA. Bogardus
Author: P. F. Brown
Author: Edgar Streit
Author: 
Author: David MacLeish. Smith
Author: National Aeronautics and Space Administration (NASA)
Author: Stanley Wallerstein
Author: J. J. C. Hoo
Author: P. W. Holmes