i know what shot peening does(the purpose), but can anyone explain to me how exactly its done...and how it works

 

yeah i would like to hear this also..

 

In very lehmans terminology, it works much like a sand blasting machine.

The actual process is pretty hairy to describe, I could, but if you aren't an engineering major, it would sound like this:

"Blah blah, blah blah blah."

 

explain it anyway...

 

Taken from http://www.shotpeening.com/theory.html

Surface Improvement - Steel Shot Peening or Glass Bead Peening

The surface of all metal parts contain some degree of micro-cracking, tiny cracks, discontinuties or even tool marks that can be a source of failure.

When a metal part is stressed and subjected to cyclic loading these micro-cracks enlarge and propogate through the part.

At some point in time the part will fail.

Normally, tensile stresses concentrates at the top or bottom of crack during loading.

However, the compressive skin created by peening tends to cancel out the tensile stresses and the cracks do not propogate.

Cyclic fatigue failures generally begin at the surface defects or stress concentrations known as stress raisers. Examples of high stress areas are machine marks, scratches, corners or holes, fillets, keyways, splines or other changes and interruptions in the smooth surfaces of metal.

Peening improves fatigue life, strength, operation and corrosion resistance.

Reliability of parts is enhanced as this treatment provides repeatedly uniform finishes, surface durability and wearing qualities.

All surface stresses and most internal stresses can be relieved by peening. Surface stresses resulting from ordinary machining operations may be transformed into hard-wearing compressive stresses.

Shot Peening:
- increases fatigue resistance
- increases stress corrosion resistance
- improves surface finish
- increases wear resistance
- improves coating adhesion

 

Right.

Hmmm its been 11 years since I have my engineering classes on properties of metals, but that soudns all right to me.

Similar, in its ways to 'Case Hardening', which you've all seen on padlocks.

Hard metal is generally stronger in tensile strength, and sheer strength, but also more brittle. Think about a hacksaw blade or drill bit, they are hard as hell, and strong, but they snap easily.

Softer steel is more resistant to shock loads, but not as strong. If you combine the two, you get a hard, durable outside, and a shock resistant core. Thats what they do to padlocks, to make it hard to cut, and hard to break with a chisel at the same time.

So, how does that apply here? Same concept. Shot peenig is blasting the rods with steel pellets, to harden the outside. And like was said, it smooths off all the sharper edges, which is where stress cracks start.

Factory rods are shot peened. If you have machining done on them, like clearancing, lightening, grinding for balancing, etc, that will remove the thin hardened layer, and they should be re-shot-peened..

 

ok...thats sounds pretty familar to what i've heard in the past, but are the factory honda rods really shotpeened? i mean, that would make them pretty good rods, for the b16a and b18c rods i thought those were cast iron, wheras the b16b and b18c5 were forged. correct me if i'm wrong

 

stock rods are not shotpeened

 

I also heard that stock rods, on most cars, are shot peened. You should only shot-peen rods that have had the surace tampered with.

 

tampered with? what i wanted to increase the strength of the rod w/out going out and buying a set of forged ones...wouldn't that justify shot peening?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SimbaDogg &raquo;</TD></TR><TR><TD CLASS="quote">tampered with? what i wanted to increase the strength of the rod w/out going out and buying a set of forged ones...wouldn't that justify shot peening?</TD></TR></TABLE>

It would, and that's probably why Honda went ahead and did it for you. Doing it again will not accomplish anything.

 

from every building that i've ever talked to...honda rods are NOT shotpeened from the factory