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Show HILL TOP TIMES Friday, Dtwmbw 7, 1 984 Mew 5in)Sp)ecDini fleslh)iriiDqUG tory Branch, recognized the problem with the existing magnetic particle inspection specifications and performed By Riney Lind PRAM Program Manager A new magnetic particle inspection technique is being used by the Quality Assurance Division, Directorate of Maintenance, to detect cracking in steel parts which cannot be detected by the unaided eye. some preliminary analysis on a C--5 aircraft main axle. Their work suggested the magnetizing currents recommended in the technical orders and military specifications could be reduced to half the specified current and result in a more reliable inspection. Also, lower currents would result in weaker residual magnetic fields which can more easily be removed after inspection. A productivity, reliability, availability, and maintainability project was initiated here to develop inspection procedures for testing hardware for weapons systems overhauled here. Five differently shaped steel components were evaluated to determine the reliability of magnetic particle inspection with magnetizing currents ranging from 100 to 2,500 amperes. In each case, the technical order required a miximum of 3,500 amperes and several different inspection positions; whereas, measurements of magnetization leakage fields and appearance of real or artificial defects using the PRAM tests indicated that half this amperage and half the positions specified provided an optimum inspec- -' tion procedure. The inspection is performed by a machine which introduces a magnetic field into steel parts. The magnetic field sets up north and south poles at surface defects and attracts magnetized fluorescent particles that cluster by the defect making it easily visible. The technical orders and military specifications governing magnetic particle inspections use standard formulas to , determine required magnetizing currents for each inspection. These formulas were originally derived for low strength steels; and, since most components inspected here are high strength steels often irregularly shaped, standard formulas cannot be realistically applied. Two problems are usually encountered when applying the stanquired and actually mask defects, and second, the highly magnetized fields to remove after inspection. Fred Seppi, Jack Clark and John Houskeeper, Metallurgical Labora PEARL HARBOR DAY Dec dbfiedte cracked sfee Action has been taken to incorporate the PRAM developed inspection procedures into existing directives for the five parts involved with this study. Further implementation of the developed procedures will be accomplished by revision of approximately 50 other directives currently specifying questionable inspection procedures. Additionally, a directive for inspection of general shapes rather than specific items will be published. The military standard which governs magnetic particle inspection for the Air Force is currently being corrected to incorporate the data on high strength steels generated during the PRAM study. The PRAM investment savof $11,720 will result in five-yea-r of ings $754,540. 1 ''!'::'::li:5:i;i': llflr and John Houskeeper of the Metallurgical Laboratory in the Directorate of Maintenance use new equipment to obtain magnetic field main landing gear axle. strength on values for Jack Clark 7 (I) C-5- A laze King The Perfect Gift For The House & Family Conventional m Burns 14 hours-plu-s m Bums Vi less wood m Seduced clearance Disc TIUDAS Brakes Drum Brakes (Front or Rear Axle) (Front Axle) Resurface drums Inspect wheel cylinders and springs Inspect hydraulic system New guaranteed linings Readjust brakes Repack wheel bearings Resurface rotors Inspect calipers New guaranteed pads (Metallic pads extra) BRAI(5IOP Catalytic less firewood M m shield m Automatic thermostat d m Double-Plenu- m firebrick-line- d firebox m Optional outside combustion air intake kit m Optional Slay Clean glass door Optional royal oak 'n brass trim vnvmfy lo average conventional stove at 4535 ' M ' urn 621-860- 220 Wash. 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Addi- nnnnn 7 high-streng- th dard formulas here: first, the specified currents are much higher than re- are difficult -- kits , Stone and Stove Center Complete Ogden'sSeeMost showroom our in our displays complete |