This paper summarizes several corrosion tests and in service trials of chain with different surface conditions operated in corrosive underground mining environment of a Queensland coal mine. ...Galvanized chain has been employed by more and more Australian coal mines, despite the stigma against such chain formed more than a decade ago regarding susceptibility of galvanized chain to stress corrosion cracking (SCC). Trials of short lengths of galvanized links and salt spray testing were used to verify the effectiveness of the galvanized chains.
This paper presents the results of a number of investigations undertaken over several years into the fracture of wires at the socket termination positions of dragline boom support strands.
Fracture ...was the result of fatigue cracking primarily within the range 50 mm to 150 mm from the socket and was typically manifested internally at positions of wire cross-over. Wire fractures in the outer layer of wires, if present, generally occurred late in the process of cracking.
•Details fatigue cracking in dragline boom support strands not previously found in the literature.•Wire fracture distribution in these cables appears to differ from that reported for smaller diameter cables.•Presents information on wire fracture distribution relative to the termination.
•Axial fractures exhibited a two tone, two stage process not previously reported.•Fractures faces exhibited intergranular path not fatigue crack propagation.•Fracture due to Hydrogen embrittlement of ...a bearing due to lubricant breakdown.•Oil formulated to resist WEC did not prevent lubricant degradation and H + absorption.•Multiple axial fractures arise from ‘waviness’ in the interference fit.
This paper presents the results of an examination of a single row tapered roller bearing from a 650 t Face shovel swing transmission gearbox that exhibited an unusual pattern of axial fracture.
The bearing sustained multiple axial fractures around the inner ring (cone) many of which exhibited a fracture face with a two tone pattern, suggesting a two stage fracture, comprising a dark internal region of lubricant discolouration and a bright fresh fracture border. SEM examination indicated the discoloured region to have fractured following an intergranular path consistent with hydrogen embrittlement arising from lubricant breakdown, while the border region exhibited a cleavage fracture.
A brake assembly piston rod from a RAAF aircraft had fractured as a result of tensile fatigue that had initiated within a relatively pronounced machining mark at the change in section from a stress ...relief groove to piston rod body. While cracking could be detected under Scanning Electron Microscope (SEM) examination, crack width was such that high sensitivity fluorescent dye penetrant inspection methods did not highlight cracking and ultra-high sensitivity fluorescent dye penetrant indicated the presence of cracking but not its full length. At the time of writing the OEM recommendations are for high sensitivity fluorescent dye penetration inspection to determine the presence of cracking within the stress relief groove. Approximately 360 similar aircraft (which includes a number of different variants), were understood to be in service, operating in fourteen (14) countries around the world. The risk to the aircraft and crew should a piston rod with an undetected or undetectable crack fail during an aborted take-off or during landing is potentially catastrophic.
A sensitive method for the determination of hyoscine (scopolamine) in urine is described. After concentration and "clean-up" on C18 and CN solid phase extraction columns, hyoscine was quantified by ...high performance liquid chromatography with coulometric detection (oxidation at +0.9 V). The limit of detection was 5 ng per sample and the precision for 5 mL samples containing 2 ng/mL was 12.3%. The method was applied to urine samples collected from 12 volunteers wearing Scopoderm TTS patches. The mean excretion rate of unmetabolized hyoscine was 0.45 micrograms/h and 87% of the total hyoscine was present as conjugates. Apohyoscine (aposcopolamine) was identified as a urinary metabolite. The significance of this with regard to hyoscine assays is discussed.
