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Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001820
EISBN: 978-1-62708-241-9
... Abstract A group of control valves that regulate production in a field of sour gas wellheads performed satisfactorily for three years before pits and cracks were detected during an inspection. One of the valves was examined using chemical and microstructural analysis to determine the cause of...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003553
EISBN: 978-1-62708-180-1
... Abstract This article commences with a discussion on the characteristics of stress-corrosion cracking (SCC) and describes crack initiation and propagation during SCC. It reviews the various mechanisms of SCC and addresses electrochemical and stress-sorption theories. The article explains the...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0046870
EISBN: 978-1-62708-217-4
... Abstract A hollow, splined alloy steel aircraft shaft (machined from an AMS 6415 steel forging – approximately the same composition as 4340 steel – then quenched and tempered to a hardness of 44.5 to 49 HRC) cracked in service after more than 10,000 h of flight time. The inner surface of the...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0006387
EISBN: 978-1-62708-217-4
... Abstract A routine examination on a seat ejection system found that the catapult attachment swivel fabricated from 7075-T651 aluminum alloy plate contained cracks on opposite sides of the part. This swivel, or bath tub, does not experience extreme loads prior to activation of the catapult...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c9001560
EISBN: 978-1-62708-217-4
... Abstract Military aircraft use a cartridge ignition system for emergency engine starts. Analysis of premature failures of steel (AISI 4340) breech chambers in which the solid propellant cartridges were burned identified corrosion as one problem with an indication that stress-corrosion cracking...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0091674
EISBN: 978-1-62708-217-4
... Abstract Forged aluminum alloy 2014-T6 hinge brackets in naval aircraft rudder and aileron linkages were found cracked in service. The cracks were in the hinge lugs, adjacent to a bushing made of cadmium-plated 4130 steel. Investigation (visual inspection and 250X micrographs) supported the...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0048616
EISBN: 978-1-62708-217-4
... Intergranular precipitation Shot peening 431 UNS S43100 Stress-corrosion cracking The T-bolt shown in Fig. 1(a) was part of the coupling for a bleed air duct of a jet engine on a transport plane. Specifications required that the 4.8-mm ( 3 16 -in.) diam T-bolt be made of AISI type 431...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0091678
EISBN: 978-1-62708-217-4
.... Aircraft components Forgings Lugs Marine environments 2014-T6 UNS A92014 Intergranular corrosion Pitting corrosion Stress-corrosion cracking During a routine shear-pin check, the end lug on the barrel of the forward canopy actuator on a naval aircraft was found to have fractured. The lug was...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c9001538
EISBN: 978-1-62708-217-4
... Abstract Examination of a cracked nose landing gear cylinder made of AISI 4340 Cr-Mo-Ni alloy steel proved that the part started to fail on the inside diam. When the nucleus of the stress-corrosion crack was studied in detail, iron oxide was found on the fracture surface. A 6500x micrograph...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c9001540
EISBN: 978-1-62708-217-4
... Abstract Ground maintenance personnel discovered hydraulic fluid leaking from two small cracks in a main landing gear cylinder made from AISI 4340 Cr-Mo-Ni alloy steel. Failure of the part had initiated on the ID of the cylinder. Numerous cracks were found under the chromium plate. A 6500x...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0047076
EISBN: 978-1-62708-217-4
... Abstract Two cracks were discovered in a deck plate of an aircraft during overhaul and repair after 659 h of service. The cracks were on opposite sides of the deck plate in the flange joggles. The plate had been formed from 7178-T6 aluminum alloy sheet. Analysis (visual inspection, 0.2x/2x/2.3x...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0048665
EISBN: 978-1-62708-217-4
... heavily corroded with chromium plating missing. A heavily corroded intergranular fracture mode was revealed by chromium-carbon replicas of the areas of fracture origin. Deep corrosion pits adjacent to the fracture origins and directly beneath cracks in the chromium plate were revealed by metallographic...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c9001542
EISBN: 978-1-62708-217-4
... Abstract A nose landing gear cylinder made from AISI 4340 Ni-Cr-Mo alloy steel was found cracked and leaking, causing partial depressurization. Investigation revealed the crack to be a stress-corrosion type, judging by the 6500x electron fractograph. It had started in a region of concentrated...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0047125
EISBN: 978-1-62708-217-4
... Abstract A commercial aircraft wheel half, machined from an aluminum alloy 2014 forging that had been heat treated to the T6 temper, was removed from service because a crack was discovered in the area of the grease-dam radius during a routine inspection. Neither the total number of landings nor...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0006409
EISBN: 978-1-62708-217-4
... Abstract Pitostatic system connectors were being found cracked on several aircraft. Two of the cracked connectors made of 2024-T351 aluminum alloy were submitted for failure analysis. The connectors had cut pipelike threads that were sealed with Teflon-type tape when installed. Longitudinal...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0006413
EISBN: 978-1-62708-217-4
... Abstract Examination of a 7075-T6 aluminum alloy pylon strut revealed cracks in two locations on the ears of the strut. Because the part was still intact, the cracks had to be forced open so that the fractures could be examined. Scanning electron microscopy (SEM) of the opened cracks showed...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0089722
EISBN: 978-1-62708-217-4
... provided no support and offered no resistance to vibration. The line was leaking hydraulic fluid at the nut end of the elbow. Investigation supported the conclusion that failure was by fatigue cracking initiated from a notch at the root of the weld and was propagated by cyclic loading of the tubing as the...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0047856
EISBN: 978-1-62708-217-4
... Abstract The master connecting rod of a reciprocating aircraft engine revealed cracks during routine inspection. The rods were forged from 4337 (AMS 6412) steel and heat treated to a specified hardness of 36 to 40 HRC. H-shaped cracks in the wall between the knuckle-pin flanges were revealed by...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c0047583
EISBN: 978-1-62708-217-4
... Abstract An aircraft fuel-nozzle-support assembly exhibited cracks along the periphery of a fusion weld that attached a support arm to a fairing in a joint that approximated a T-shape in cross section. The base metal was type 321 stainless steel. Examination showed a good-quality weld...
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.aero.c9001745
EISBN: 978-1-62708-217-4
... Abstract A 2000-T6 aluminum alloy bracket failed in a coastal environment because corrosive chlorides got between the bracket and attachment bolt. The material used for the part was susceptible to stress corrosion under the service conditions. Cracking may have been aggravated by galvanic...