Failure Analysis Process – Part 1: Background Information
Written by Matthew Bridson, Metallurgist, IST
As a metallurgist at the Institute of Spring Technology, I’ve spent years investigating why springs fail. Over time, I’ve realised that every failure tells a story, and our role is to uncover that story in full. In this first article of a series on our failure analysis process, I want to share my perspective on why background information is the cornerstone of every investigation.
Why Background Information Matters
Background information is incredibly important for our investigation, it provides us with a
foundation to put a full story together and find the root cause of the failure. The background
information we look for includes a spring design, to check if the spring has any underlying
issues that might lead to premature failure. We also request a material certification. Materials
have varying properties which can be beneficial to the springs function. It also points us in
the right direction when it comes to what to expect from the microstructure, hardness results
and SEM/EDX readings
Knowing the full spring manufacturing processes is key for identifying any issues within the production, such as grinding, heat treatment, surface coatings and shot peening. For example, electroplating some materials can lead to hydrogen embrittlement.
This could be a key piece of knowledge in understanding the failure, and the recommendations we give to stop future failures. It is beneficial for us to be aware of the atmosphere in which the spring is working. It can help us understand more about what the spring may have been exposed to, which may affect its life. Even if the customer believes the working environment could not influence the spring, e.g. working in oil, it is always useful to know, as atmospheres such as these can become contaminated. This will also allow us to judge the coating used, as it might not be sufficient to protect the spring within the atmosphere it is working.
Information about when the spring failed tells us if it failed prematurely or not. The speed of
failure can often help point us in the direction of a particular issue. Some springs can fail
while they are being prestressed/scragged or even while they are being installed!
Finally, it is useful to understand if any other failure analysis has been completed on the
spring. Everything we do is unbiased, so we don’t let previous studies affect our approach,
however it can sometimes explain why there are already cut faces, or some damage to the
spring which can be ignored as it happened after the failure.
How We Apply This Knowledge
At IST, we offer a range of failure analysis packages – Bronze, Silver, and our comprehensive Gold package. The Gold package reflects our most in-depth approach, including SEM/EDX, chemical analysis, design checks with optimization, and consultation meetings before and after the investigation.
But regardless of the package, the first step is always the same: gather thorough, relevant background information. This ensures that the investigation is rooted in fact, not assumption, and allows us to deliver recommendations that truly prevent repeat failures.
Part 2 Coming soon!
In the next article of this series, I will discuss our initial examination process – the step where we begin to piece together the clues that reveal why a spring failed. Understanding the methodology behind these examinations gives insight into how careful, expert analysis can make all the difference.
If you want to explore how our metallurgical expertise can help solve your spring failures, or if you’d like to discuss a failure analysis project, contact our team today