Conducting a materials failure analysis requires a carefully planned series of steps intended to
arrive at the cause of the problem. Consistent with the current trend towards better accountability
and responsibility, failure analysis purpose has been extended in deciding which party may be
liable for losses, be they loss of production, property damage, injury, or fatality [1]. Hence it
increases the importance of proper implementation of characterization tools in failure analysis to
rightly identify the failure mode.
Present work discusses a few case studies to shed light upon the importance of the metallurgical
characterization tools and techniques in identification of correct failure mode. Some typical case
studies where metallography plays a very important role have been discussed, such as improper
welding joints which led to premature failure, sensitization and stress corrosion cracking in S.S.,
improper heat treatment and forging indicated the microstructures which led to the premature
failure. These cases are examples of only a few laboratory based investigations which justify that
without metallography it is not possible to diagnose the causes of premature failures.
Generally, examination of failed components commence with the low-power stereomicroscope
whereas hand-held magnifying lenses are still in wide use by experts to study fractures mostly
limited now for field purpose [2]. Metallographic examination typically is performed after nondestructive
and macroscopic examination procedures while using the light optical microscopy
which helps to assess the failure mode with respect to material defects, shortcomings in
processing, metallurgical changes etc. Since light optical microscopy has limited value for direct
observation of fracture surfaces (more limited for metals than non-metals), with still more factual
information can be gathered by scanning electron microscopy at higher magnification.

Corrosion, either internal or external, along with other types of defects on pipelines eventually lead to leaks without proper treatment. This gives rise to several issues, including environmental and safety hazards, and in case of pipe leaks in a plant, a loss of the efficiency of the process or, ultimately, failure of the process. Replacing the corroded pipelines (piping) can be difficult, costly and time consuming especially for plant. A required shutdown causes major economic loss. Thus, instead of a replacement of the defected pipelines, the installation of online repair is a better option.
Repairs of pipelines include metallic and non-metallic repairs. Metallic repairs generally require welding or hot works which is not suitable for online repair of pipes containing hydrocarbons. In such cases the use of non-metallic composite repairs is the optimum solution. A non-metallic composite repair system is a system used to reinforce structures using a fiber equipped with a thermoset epoxy system. The epoxy system consists of a hardener and a resin which, after mixing, become solid through a polymerization reaction after a short duration of time, a process that is called curing. Depending on the temperature, the duration of time changes in an inverse relation. The higher the temperature, the smaller the duration of time needed for curing. This system can be used to reinforce pipelines with both external and internal corrosion and it can be used on Straight Pipes, Tees, Elbows, Flanges and weld joints. The repair system can also be installed online without the need for a shutdown in a short amount of time and a small requirement of labor intensity, making it cost effective. It is also environmentally friendly. In this paper we are going to present cases that were resolved by our company that demonstrate how successful these non-metallic composite repairs are and how diverse their applications can be