repair mergers

[Fulvio Romano]

time ago I came across a methodology for repairing aluminum and nibral castings. when a fusion comes out with an excessive porosity (sometimes true craters) that perhaps sharpens from mechanical processing it is possible to "care" through a filler resin. I used it for a particularly important structural component and was accepted by a notified body, so safe stuff.

Who helps me recover the method?

 

[PierArg]

in my field is used impregnation and resin is named imprex.
each company has its own process (I imagine the resin is something "patented" or "owner").
the method will doubt you because, for what I know, it varies from company to company.

 

[scalva]

Yes,
look for aluminum impregnation. is made with appropriate resins and procedures. That's what it is.

 

[Fulvio Romano]

Okay, thank you. I tried reading something on the internet.
But let me understand a few things:

1. I read that the impregnation method works well for microporosity, but not for porosity visible to the naked eye. those that flow from my pieces after processing vary between 0.2mm and 3mm. Does the same work?

2. If the process is fusion > processing > impregnation > black anodising, I imagine that anodising does not take on the impregnated part, then on the black will see dots of the size of some millimeter of the color of the resin? If my problem was purely aesthetic I could use a black resin and solve the problem so?

3. If instead my problem was resistance to fatigue, knowing that a superficial porosity worsens this feature, an impregnation again lengthens the time of incipient fatigue damage (the number of cycles within which the damage does not appear) or has no effect?

Thank you.

♪

 

[PierArg]

I think you should try to contact some potential suppliers and ask.
It's such a "non-standard" process that doesn't allow a unique solution.

1. on the 3mm of porosity I have no experience...even if I begin to suspect that fusion or design is not the maximum.

2. Good question, you have to ask some supplier.

3. for my experience an impregnated component has a far greater fatigue resistance than that unpregnated.

 

[simone omi]

hi, when castings have real holes or high porosity, the foundries close them with the welder and then smooth and sanded, if the welder is good it is hard to see.
I saw this operation used for prototype fusions or small series, even because otherwise the model or the foundry process is corrected.
impregnation was used to ensure the sealing of pressure liquids....

 

[Fulvio Romano]

hi, when castings have real holes or high porosity, the foundries close them with the welder and then smooth and sanded, if the welder is good it is hard to see.
I saw this operation used for prototype fusions or small series, even because otherwise the model or the foundry process is corrected.
impregnation was used to ensure the sealing of pressure liquids....

I am talking about aluminum jets worth a couple of euros each. For example, frames of engines from a few thousand watts. porosity (but we also call them holes) does not actually give technical problems and have been accepted for years by customers. customers who today become more demanding from the point of view also aesthetic and begin to declare non-compliant objects that have been for years.

 

[scalva]

I did that treatment years ago on fusion fittings that also worked at high pressure, for porosity problems on certain batches. the pieces were then worked and anodized.
the anodization, which was not the maximum as an aesthetic, after impregnation it was not possible to make it.
However in the end we abandoned castings and made the workpieces.
Unfortunately I do not remember where I had done the treatment, but it was similar to those you find on the internet now.

 

[Stefano5]

I had a similar experience when I was responsible for a well-known company that produces access automation. diefusions are very economical, but when work porosity is inexorably out. We also felt an impregnation with loctite, but the result was not definitive and did not cover all cases. we solved by modifying the die castings so as to limit the processes of removal to some tenth of depth, and preferring work without removal as the roller.