ajschult

Anyone know what stock pushrods for the LT1 or LS1 are made from? Any info on where to find stock info would also be helpful. This is for a school project in a Materials Science class. We are comparing stock to aftermarket pushrods. Thanks

evilundisguised

No, but I'd just like to say I'm envious because I never did anything practical in my materials science classes Sounds like fun, is it for your major?

OldSStroker

It's a good chance the stock PRs are made from DOM (Drawn Over Mandrel) carbon steel (1016-1026) tubing. If you are sectioning, mounting, polishing and etching the samples (which should be a minimum, IMO), look for structure, thru or case hardening in the aftermarker PRs as well as grainstructure. You should be able to tell DOM from CDS (Cold Drawn Seamless) tubing.

How about posting the photomicrographs and microhardness results of your samples when you are done.

ajschult

Our professor let us choose whatever we wanted in testing, just had to come up with some good reasons. My group came up with a scenario where we are given a broken pushrod and are supposed to determine what brand it is. Our main objective is basically to compare chromemoly to stock.
Yeah materials science is a requirement for mechanical engineering majors.

ajschult

Thanks for the info guys. It will help in determining what the theoretical material data should be before we start actual testing.

ajschult

We actually did some rockwell hardness testing yesterday, but thats as far as we are right now. No surprise that comp's chrome moly had a much higher hardness than the stockers. I dont have the data in front of me, but chrome moly was around 120 (B scale), and stockers were in the mid 80's (B scale). So far thats all we have done, pretty much just started.

Unfortunately I dont think we will be able to do microscopic level testing to see grain structures. But that is something I will certainly ask my ta about. At this level of a course they dont let us play with much of the cool equipment. Our materials science lab has hardness testing equipment, tensile strength testing equipment, and hopefully we will be able to get into one of the other labs at the college to use compression testing equipment.

OldSStroker

Hmmmmm. Doesn't the Rockwell B scale (RHB) stop at about 100? You got 120? Theoretically that would be in the HRC range. You are accounting for the diameter correction, right?

How about looking at superficial hardness just in case you have a case hardened PR instead of a thru hardened one? Know why?

How do you plan to tell 4130/4140 from 10XX steel just with hardness?

If they won't let you use the expensive equipment, read up on spark testng and try that.

If I wanted an A in the course, I'd find a local well equipped heat treating place and have the sections mounted, micro hardness tested and photomicrographed (if that is a word). That might be $50-$100 (or less with a "student" discount), but you'd all learn something...maybe even the prof.

ajschult

Yeah, that is in the C range. The values are mainly for comparisons sake. We will also be disecting the pushrods to measure the hardness of the inside wall as well. Right now the class is focused on plastic/elastic deformation and failures. So our main goal is to determine how much stronger comps chrome molys are than stockers. To do so we will be measuring the tensile and compressive force needed for fracture/deformation. If it were an upper level course I would certainly look into having some analysis conducted, but since it is not we are going to stick with what is available in the lab. Something like that would make a good senior design project, I'll keep it mind for next semester. Thanks for the help.

evilundisguised

I'll be doing this with a guideplate that one member (wrd1972) put through his own case hardening treatment... http://web.camaross.com/forums/showt...=case+hardened

evilundisguised

Was this in the cross section or the outer suface?

ajschult

it was the outer hardness, not sure how we could do the cross sectional hardness. we do plan on doing the inner hardness though. again the values as oldsstroker pointed out for the chrome moly are technically in the C scale, but for comparisons sake they work well.

OldSStroker

You mount a transverse section and do a microhardness. You should be able to find the procedure online. I'm too lazy to look it up tonite.

Hardness checking on a concave radius of about .090 isn't easy nor is it very accurate.

FWIW using a hardness scale well out of it's effective range really doesn't work well for comparisons.