Keep that to PM's.

 

The control arms are likely made from ductile cast iron rather than grey cast iron. The difference: grey iron(used in engine blocks) has a higher thermal transfer coefficent and a little better machinability due to the graphite flakes dispersed through the microstructure. Ductile iron has graphite nodules (due to the addition of small amounts of Magnesium), which has a little higher elongation (more ductility) and fracture toughness. This is why this material is used for suspension components rather than grey iron. And yes, it can bend but not nearly as much as most grades of steel you are accustomed to.

BTW: I am a metallurgist.

 

i had bent control arms on my car ofter a accident and the knuckle broke

 

Thanks for the explanation slalom44. BTW, I could definitely tell that you were a metallurgist simply from your very descriptive and accurate explanation. Either a metallurgist or material scientist/engineer.

 

Did I say something offensive? I merely commented on that fact that you would have to hit a curb pretty hard to cause the lower control arm to break entirely. Usually your alignment is thrown off specs even if you hit it with a moderate impact with maybe bending but breakage is pretty rare w/o a collision. If I was over the line with this specific comment then I apologize. Perhaps it was a comment better expressed as a PM.

 

dont mind Alex...he always comes across as an ass...just ignore him when he's like that

Ohh...and while it wasn't my S, on my Eclipse, I bent a control arm REALLY bad...but I forget if it was cast Iron, or forged steel...I think someone told me it was forged steel

 

Duly noted!

 

Hey now, go back and reread what I quoted. I intentionally misquoted you and gave it some sexual connotations. That's why I said to keep it to PM's.

 

Alex, man, you're something else! So you basically spend part of your time reading others' posts hoping you can string some sentence fragments together to give a sexual connotation. Keep up the good work Yeah, what threw me was the fact that you followed up your comment with a frown.

 

Rio: Actually the statement is accurate. If you have a lot of (metallurgical) defects whether by thermal stress or by deformation or whatever, the strength of the part can actually increase. Voids are typically the only thing that makes metals weaker beause they introduce stress concentrations that cause premature cracking and failure.

Carbon steels are more brittle in that they will break before they bend significantly. They are indeed stronger because carbon precipitates out and prevents the material from deforming easily (they increase stiffness). I believe I was incomplete in my descripition the first time round and hopefully this calrifies. In any case slalom did a good job.

Bassem