High strength low alloy (HSLA) steel with a nominal composition of 0.15C–1.25Cr–1Mo–0.25V is being extensively used in space programme. Owing to its ease of fabrication and welding, a tank was fabricated out of this alloy. The tank is used to contain strontium per chlorate which on combustion develop secondary thrust, effectively used during attitude control of satellite launch vehicle. During one of the routine qualification tests, a tank had failed at an internal pressure of 109 bar, against a designed proof pressure of 120 bar.
Failure was initiated from long seam weld of a cylindrical shell and propagated into the parent material thereafter. Detailed metallurgical investigation has been carried out to understand the cause of failure. …..Read more
Catastrophic failure due to internal corrosion of a 10 m high, 8 m diameter steel storage tank containing approximately 350 m3of waste solvent led to a significant environmental incident in 2009. An investigation was carried out to establish the root cause and to learn lessons that might prevent a reoccurrence.
An interesting paper in « Case study in Engineering Failure Analysis » published on ScienceDirect.com. This paper dealt with the analysis of a novel chassis for figure roller skates, made of P-AlMgSi alloy, which experienced a premature failure. An integrated approach had to be used to overcome the several criticalities of the study. The research led to the individuation of the primary cause of failure, standing in bending fatigue, due to the high number of jumps (i.e.: fatigue cycles) being performed during figure skating training. A solution to the problem was suggested, which led to an improved and optimized project of the chassis with positive outcomes (from the technical and mechanical points of view) in its use.