So, for almost 50 years I have had the opportunity to investigate various material/component failures, and with all the variables, two things have been fairly consistent. The first statement that is most often heard, aside from; “Don’t look at me!” is, “It looks like defective material.” Eventually, and more often than not, the actual reason for failure involves something other than material defect; incorrect material, design and engineering misunderstandings relative to material availability and the creativeness of people when it comes to overcoming those obstacles, changes in the application or environment, or a mishap in the installation, assembly, disassembly or earlier repair, etc.
The instances of material defect are very often the least contributory to failure. Perhaps the cleanliness or toughness of the steel was not up to the task. But that is not really a defect. It is a specification problem.
There are of course defects in material. That is true with any product. The point here is, don’t make that the first assumption. Besides, you are more apt to be able to quickly fix the problems that are most often contributory, right there on location, if you can identify them early.
Not to be MOTO (Master of the Obvious) here, if you are in maintenance you already have developed a mental checklist to identify the most frequent culprits; steel grade, toughness, change in temperature, alignment, moisture, chemical environment, load, vibration, lubrication, wear, surrounding forces, surface scratches, gouges, or cuts, new employees (Don’t look at me!!), sabotage, Keyser Söze, Russian interference, inc.
When the usual suspects have been ruled out, begin planning for some failure analysis testing. You will eventually need to provide a specimen of the failed piece (preferably at least 4″ to either side of the break). Contact your supplier and request their assistance. They may contact their local independent testing facilities, may have their own lab, and/or, they may contact the producing mill. I have been reminded; “In maintenance, as in life, most of our wounds are self-inflicted”.
Routine industrial applications can destroy some of the toughest materials known. And that is just during the daily conduct of business. Be mindful of the effects of those forces and respect the potential for catastrophic failure (whether it results from material defect or not). Make use of appropriate safety gear, stay alert, and if you don’t know, ask!
-Howard Thomas, April 9th 2019