Failure Analysis / Investigation

Failure analysis or investigation is the process of collecting and analysing facts or data to determine the root cause of a failure. This involves collecting data about operating conditions, visual examination of the failed product or component, fractography, non-destructive testing, evaluation of mechanical and chemical properties, metallography-microscopy, spectroscopy, analysis of the facts and findings, root cause conclusion and recommendations to prevent the failure from recurring.

This process is vital where failure of components could result in injuries, deaths, or millions of dollars in damages and loss of production. 

LMATS also offers Expert Witness Services for third party audits, dispute resolution or litigation. As an Expert Witness, LMATS team can provide an independent opinion about a subject matter or a consumer product, technical adviser for vendor qualification or approval, conformance to industry specifications or a forensic review.

Common modes of failures include:

• Fatigue failure
• Overload failure
• Erosion and Wear failure
• Various forms of Corrosion failure
• Dezincification,
• Graphitisation, SSC, HIC, etc
• Sensitization of stainless steel
• Stress corrosion cracking
• Ductile and brittle fractures
• Hydrogen embrittlement
• Liquid metal embrittlement
• Creep and stress rupture

Common causes of failures include:

• Incorrect material used
• Manufacturing defects e.g. Casting, forging, welding discontinuities
• Incorrect heat treatments
• Product not manufactured to the Design requirements.
• Machining or fabrication tolerances not achieved
• Inadequate environmental protection/control
• Inadequate maintenance
• Overloading or incorrect use
• Assembly errors
• Design errors
• Unforeseen operating conditions

LMATS ' failure investigators have an extensive range of experience across Australia, including materials, components and product for all industries. Some common examples are:

• Heat Exchangers from Oil & Gas, Refineries, Power Generation, Paper mills, Chemical plants
• Automotive and Locomotive parts e.g. Wheels, steering, gears, axles, engine block, Crack shaft, Connecting rods, fuel lines, etc
• Aerospace parts e.g. Landing gear, trunnion, Fuel lines, Fuel pumps, Universal column, etc
• Power station – Boiler wall tubes, valves,
• Pressure vessel and pipes – Aluminium Smelter
• Fabricated joints and welded assemblies, thermit welds
• Rolling stock components – Train wheels, Rails, Rail welds, Bogies, couplers, etc
• Cooling Towers parts – Caster bolts, valves, tubes, etc
• Water industry parts – Valves, pipes, dam hydraulics,
• Long distance pipelines – Ammonia export line, White oil transfer line, gas transmission
• Fasteners – Bolts, nuts, studs, assemblies, etc
• Mining components and assemblies

Case Study

The image below is a high magnification (~5000X) Scanning Electron Microscope (SEM) image of a stainless steel fatigue fracture. The micrograph revealed various cracks through rounded voids. These were determined to be the former location of sulphide inclusions that were dissipated as a result of loose bonding with the metal matrix. The geometry of the inclusions provided a stress-concentration, leading to the fatigue micro-cracks that can be observed in the image.
 
The failure investigation revealed the fracture was due to inappropriate material selection in which the presence of sulphide inclusions in the steel contributed to cyclic fatigue failure. By revealing the cause of failure, LMATS investigation allowed corrections to be made, preventing any costly future failures.