Shot Peening WPC Treatment

[wayne petty]

just ran across this .... an interesting read .......  enjoy...

just call it a shot across the bow

http://www.turbomagazine.com/tech/turp_0902_shot_peening_wpc_treatment/index.html

[Bruce Dorsi]

Thanks, Wayne, for making me smarter!  

I never heard of the WPC process before.

I also never heard of plasma cleaning (one of the sponsored links) either.

It's good that I learn something new each day, because I forget something old each day!

[taxpyer]

In the early 80's there was a real problem with excavator booms breaking from "sweeping" materials from side to side. Guys would weld them over and over but to just have them crack again. ,,,,,,,,,,Then this old welder took an air chisel and lightly "peened" the weld and the surrounding area of the repair and ,, success! From then on any repairs to the booms were treated in this manner. Now the manufactures use different steel and no longer have this problem.

Thanks Wayne

[enjenjo]

Peening of welds is something I learned many years ago from an old time welder. I used it many times to repair shift levers, strut rods, and similar objects. I also learned about welding cast iron from him.

[wayne petty]

peening it must relieve the surface tension caused by the welding... where the metals cool they shrink causing uneven loading.. so the welded area is under more surface tension than the surrounding area..  right at the breaking point.. so any elastic properties of the metal/weld are already stretched near the point of breaking..


kinda like tightening the suspension bushings in a car with the suspension hanging..   when you take it to ride height.. it puts a twist into the rubber.   when you drive and bottom out the suspension.. it puts twice the amount of twist into the rubber than was designed in.. so it tears even though its new...

machining with a tool rips away the surface of the metal leaving distortions.. if the above is true..    grinding them removes the surface of the distorted metal.. but leaves the roots of the distortion..

perhaps boring blocks to within .010 of final size and honing the last .009+ or so out would make for a stronger cylinder wall...

there was a company that did vibration stress relieving. bolted items to a spring legged steel top table..  turned on a variable speed vibrator bolted to the table or parts..  let it run for a while..   made them stronger..

if the right speed was reached..  the harmonic resonance would do the job..  hmm....


so i wonder.. how strong one could make something..   if it was shot peened. vibration treated.. then cryogenic treated...   then coated with some spray paint..   spray paint optional..

i picked up a half horse power vibrator at a wrecking yard one day.. 120 volts ac.. $10.  i just have not figured out to bolt it to my recliner .. must weigh 50 pounds..  i figured i could use  for something eventually..
looks just like this... http://www.electricmotorwarehouse.com/Dayton/vibco/6L744.jpg

edit...
so i wonder if peening he welded areas of chrome moly chassis would reduce the chance of cracks forming...

[1800guy]

Thanks for that link - the cited article pretty much answered all questions except pricing.  I had been under the impression that shot-peening was the ultimate treatment, and that glass beading was nearly as good.  I did go to the website to look for price info, but it looks like you need to give them exact dimensions - no 'ball-park' idea of what various parts might run.  Also, I didn't see where the company is located, but I might have missed it - the website is not really geared for us cave-dwellers who still have dial-up  :cry: