[Stan Weiss]

If anybody is serious about rod metallurgy; get the "SAE" 4340 metal analysed for evidence of Magnesium Sulfide "stringers". These stringers act as crack nuclei (crack starters). We did and are wiser for finding the impurity that should not have been in there. Think we had CTC Corp in Johnstown PA perform the metallurgy inspection on our "SAE" 4340 billet crankshaft parts ( custom 2-Stroke). They found the chinesium.

https://link.springer.com/article/10...668-015-9940-9

I suppose if the supplier Sources MIL-STD SAE-4340 billets for billet rods, then you know for sure the material pedigree, and can caclulate the rod life in the application stress.

I'm not knowing how a Rod Supplier(MFG'r) certifies a red-hot SAE-4340 vat-pot as a QA Engr'r inspected Lot ( batch ).

Mark,
Can't a rod have non destructive testing done which will show what percentage of what elements it is made of? Would say an xrf metal analyzer be able to do this?

Stan

[AG]

I think graphite furnace mass spectometry is used for solid elemental analysis and that is destructive.

[242177P]

I'm not knowing how a Rod Supplier(MFG'r) certifies a red-hot SAE-4340 vat-pot as a QA Engr'r inspected Lot ( batch ).

I've always just assumed they dedicate a portion of each batch for testing. It wouldn't even have to resemble a connecting rod, an ingot might be preferable? Kinda like how construction sites pour concrete samples.

[Half-Inch Stud]

(Yes a dedicated portion... ) Testing through-sections of Sample "coupons" would suffice rather than just the surface.

The Rod Maker ought be able to provide a Certificate-of-Compliance to SAE-4340 material specifications. Oh before we all LOL that would never happen, well why not? Should be available upon request for ANY MFGR claiming Forged Rod metallurgy is built-in to their product. The Iron-Clad Guarantee.

SPS fasteners come with C-of-Cs, yet i doubt ARP will ever provide such. Yea, I said it.

As for the XRF metal analyzer; they look capable! But i do not know the Test Method details. I doubt a surface scan is all ya need. I suspect a few test are involved to assess alloy mol-fraction ( watch the sparks from a grinding wheel ), inspect nucleation sizes, and the well-understood Hardness. Somehow i figure Tensile strength gets tested which should provide Yield Strength and Modulus of Elasticity. Anybody got an Instron for that.

[Half-Inch Stud]

Fastener TQ: I use an old craftsman Torque Beam. Never a fan of the Click wrench yet I've had to use em on the job.

My stepson insisted i try/use his Snap-On Digital TQ Wrench's; OMG they are addictive during Bottom-End assy. And they are stopid-easy-capable of Angle range for finish Torque-set. The built-in accelerometers zero-out easy and provide a "meter" to show you how much angle you got, and need to get to. Intuitive after a quick intro and try.. I'd push a strong reco for the Snap-On digital TQ wrenches for achieving the more modern method of Torqueset using angle for finish TQset.

I gots the SD-Rods and duh the Rod Bolts are setup for stretch gauge, yet never relied on stretch for TQset. I'd rather retain trust in a beam wrench and the oil wetting.

Seems to me the best rods don't have "Nuts" so Stretch is impossible. TQ with Angle-to-finish-TQ is pretty slick.