casting porosity problem
casting porosity problem
(OP)
We have problems with an aluminum 356 permanent mold casting - porosity causes oil leakage from the gear box casting. When I assembled these gear boxes back in the 1970s I don't remember this being a problem. I think the foundry has either changed the process or the material. They claim they haven't. I don't believe the permanent mold could wear in a way that would cause these problems. Could it be the process (pouring too fast, cooling too fast, ??)?





RE: casting porosity problem
RE: casting porosity problem
RE: casting porosity problem
RE: casting porosity problem
RE: casting porosity problem
For aerospace and military specs the specs define the quality of the casting and the testing methods for pours etc.
Look for casters that can meet aerospace and military specs.
RE: casting porosity problem
RE: casting porosity problem
If it is a degassing problem, when you look at the holes (or cracks as you say), does the internal surface look smooth or rough?
In some of the Ni-alloy castings of my career, degassing problems that were noticable as small cracks or open "worm-holes" were smooth on the inside. Whereas real cracks were rougher, like the metal is being torn apart.
Just my experience...trying to pass along the knowledge.
~NiM
RE: casting porosity problem
that is why we impregnaste and casting that will be in contact with any sort of petrolium product
we use a vacume /presure prossess that is Mil spec 276A
Bill L
SBI
Central Ne.,USA
RE: casting porosity problem
You need to change your vendor for castings supply. What is the alloy and where is the need to deliberately add gas to make it run? Please give some more details.
RE: casting porosity problem
part of this problem left us when we bought our automatic molding machine and started to run the casting there, much better speed, helped keep cost down, good looking casting.
SBI
Central Ne.,USA
RE: casting porosity problem