Upto 3mm(0.118")?? Are you sure about that. I need to find a VG crank and cut one up for case depth hardness survey. In the 20 years of materials testing and doing case depths daily, I have never encountered a nitrided steel component having a case of >0.020" deep (measured to a industry std of 50HRC). In any case that was >0.020" the nitrided case always showed signs of cracking/ spalding. However, if the VG crank was carbo-nitrided, (ie carburized then nitrided); I can see the case being upto 3mm deep. Does any one have facts of how the VG crank was hardened? I guess we will find out once I source a crank for some destructive testing. IMHO, I would hardness check the journal before assembly, but thats just me:)
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