Heating welded pistons to check for out of round condition.

RonA

RonA

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Feb 26, 2008
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I had some pistons welded up a while back and have been wondering if they would be usable. New pistons , bowl welded up and re-machined. I have been thinking about heating one up on my pre-heating plate and seeing if it does anything odd. Should i just check them to a new stock piston an room temperature, or heat them to 200 or 300 degree's and check them then. Or should i check them at a low temerature and than at a temperature 150 or 200 degrees higher and compare the expansion rates(hard to do because bowls are different, but i can accurately check the temperature and diameter). Or would weld problems show up mainly as cracking down the road?
 
i don't see what a few hundred degrees would do for comparison. When you had them welded someone should have done a positive material idetification on each piston to find the absolute perfect weld filler material. Once that was obtained there would be a pre heat procedure as well as a post heat procedure to obtain the best strength possible for the the two similar materials to be welded. All of this should be done with controlled temps as well. Once part is finished, and after the machining is done i would guess the part would be checked with a dye penetrant for cracks or dissbondment of weld material. If all of these things are done correctly there is no reason i see for re checking, just balancing.
If your scepticle of the job done you can send them out to be tested, i would do an ultrasonic test as well as a pmi of each material.
UT straight beam or linear phased array would show you any inclusions within the weld material or dissbondment.
The pmi would varify the the two materials
 
I looked up weld test laboratories and sent an email to one. If it's too pricey(probably costs more than they are worth) I'll just scrap them and chock up another one to experience.

Thank you for the information.
 
RonA said:
I looked up weld test laboratories and sent an email to one. If it's too pricey(probably costs more than they are worth) I'll just scrap them and chock up another one to experience.

Thank you for the information.
Click to expand...

Don't scrap them, sell them to someone with a Junker Drag truck, that way if they blow up a motor, it makes the world a better place!

I'm sure someone would be willing to test an experimentally welded piston.
 
fastenal sells Magnaflux Dye Penetrant Spot Check. It is a three part process that is very easy to do. This will ONLY tell you if you have external cracks or if the material is dissimilar. I can also do this for you if you just pay shipping, we have a bit better product and lab to do this in.
 
Lrt me know what you would charge to check the welds out. I worry about the weld and the base metal having slightly different CTE values and eventually cracking.

Thank you.
 
they can be welded and no promblems ive seen my brother in law had a set done seem to work nice
 
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