Grange's law of visual examination also is from about thirty years ago. It states that you should: "First take a look at the failure at 10Xwith a magnifier, and then look again and think harder".
A lot can be learned from most mechanical failures by careful visual examination aided by a magnifier, or preferably a stereo microscope.
A couple times I have seen people claim that a failure had not occurred progressively via fatigue cracking because they could not find striations at high magnifications (~8000X) in the scanning electron microscope (SEM). However, there were concentric crack arrest markings ("beach marks") visible at low (~8X) magnifications.
Ray Grange was a metallurgist at the US Steel Research Lab. You can still find some of Ray’s 1956 work on tempering of carbon steel referenced in the Heat Treating volume 4 of the current ASM Handbook.
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Absolute correct.Have been in failure investigation for 30 year refer www.metserve.co.za 90% of failure,s can be solved without SEM.
Q. Is it possible to determine when cam and roller flaking and spalling occured? No wear shown in oil analysis or ferrography, cam and roller wear evident with spalling and flaking.
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