Aluminum as a press die?

[Jason W]

I have a question, I was day dreaming a bit the other day and came up with a bit of a head scratcher. If I were to pour aluminum into a mold for a 1 time use, would it be strong and stable enough to use as a press die for a piece of heated mild steel? Walking through it in my head I think I've come up with the answer, that aluminum would be too soft and I'd need to use something like brass, but I'd like to hear your thoughts. 

Thanks. 

[Irondragon Forge ClayWorks]

I don't think either would work very well although I don't know what kind of press you have. Maybe a picture of it would help. I would make the die out of a piece of RR track or 4130 steel.

[George N. M.]

In a press or under a hammer the softer metal will deform.  To use aluminum or brass for a die you would need to be using it with something softer.  I think that steel, even close to welding temperature, would be no softer than cold aluminum or brass even if it was softer to start with it would quickly cool to being harder than the die.  So, short answer, no, it probably would not work.

"By hammer nd hand all arts do stand."

[Jason W]

I don't have a press yet so I wouldn't be able to show a picture. What I was thinking of is making a die for a one time use only since each mold would be different and not replicatable. There really would be no point in making something that would withstand multiple uses so using a tool steel would be overkill and not effective for what I'm thinking about. The reason why I was thinking aluminum or brass is that it can be re-melted and poured again into another mold. 

[Scott NC]

  That's an interesting idea.  What thickness of mild steel are you thinking about forming.  Sheet metal or heavier?  What about your die, concave, convex, flatish?  Is it for decorative pieces?  You give me ideas now.

[JHCC]

It’s an interesting question. The melting point of aluminum is 1,221°F, while your steel is going to be around 1,700°F or higher. However, the mass of aluminum in the die would act as a heat sink that would cool the steel pretty dramatically, so you probably wouldn’t get any actual melting. At the same time, though, the steel would be losing flexibility as it loses heat. A thinner workpiece would form more easily, but lose its heat faster. Your press would therefore have to be fast enough to form the workpiece before it loses its heat, which would be a challenge if the form is very deep. The mold certainly wouldn’t work more than a couple of times at the most, so everything would have to work perfectly the first time.

In short, probably not. 

[Jason W]

With all do respect I would like to keep this idea to myself at the moment. I have a feeling that it may not have been tried yet so I'd like to see if I can perfect it then share it : ) I know I'm asking a lot but only sharing a little information, for that I apologize.

I guess the thickness would be dependant on the piece... It would be decorative but I would only need to press the die into the piece up to 1/2"? 

I was also thinking that I could dip the die into oil to prior to pressing to create a vapour jacket around the die. This may stop it from deforming for just a few seconds longer...

[Scott NC]

14 hours ago, Jason W said:

for a 1 time use

  It is an interesting idea.  Short answer, worth a try. Most new processes sound implausable at first glance.  Would it be possible to pre-heat the die?  Position rosebuds or some other setup to keep the steel hot?  Idk but it has given me the spark of an idea how to make something that's been on my mind.  Using thinner material of course.  I bet if the steel was as hot as you could get it, and you moved fast enough, a manual hand made press operated by a leveraged handle would work.  Like Jason, I'm just daydreaming.  I like the idea of one shot (or more) molds you can cast.

  No problem, I respect your desire to keep your actual plans to yourself.  It just sparked my imagination.    

Edited June 14, 2022 by Nodebt
Add last thought. Posted at same time.

[Frosty]

Jason: Without some details you can't get a meaningful answer. I suppose it's possible IF the deformation is shallow enough in thin enough deep draw sheet steel. 

In a situation like yours about the most meaningful thing I can suggest is you give it a try and let us know how it works. If it's not too deep a secret of course. What manufacturer on Earth wants to invest time in making single use press dies? Heck I don't know of a manufacturer who makes one off products, even space craft are built in multiples.

Frosty The Lucky.

[Scott NC]

  It's kind of strange that steel will start to flop down under it's own weigh when it gets hot enough but can't be molded over a form of some sort?  Especially if the heat source can be kept on it?  I keep thinking of my own idea of a convex shape.  Maybe pushing it into a convex aluminum form is utterly impossible.  I have pushed on hot steel with a pliers and made it move.  My idea is for thin metal.

  I highly doubt he is worried about manufacturers stealing his idea.  He may want to see if it works first.  Need help/try it out/perfect it/stun ifi/ make a million dollars.

[Scott NC]

  Maybe I should have said practically start to sag or flop.  I was trying to melt steel once and ruined a pair of vice grips testing it's softness...   I came close.  

 

[Jason W]

Did you just use your body weight to press into that piece? That's fantastic!

[Scott NC]

Yes.  I just pushed it into it with my hand. 

[JHCC]

Ooh, squishy.

[Scott NC]

  Just about liqiufied it. 

[ThomasPowers]

Have you researched explosive forming?  You can do explosive repoussé with disposable dies.  It is rather expensive though.

A lot of die issues hinge on how fast the top die moves.  A hand cranked hydraulic press is not going to work.  OTOH have you looked into screw presses; I've used mine for coining. The pressure spike at the bottom/reversal helps "shoot" the planchet into the die cavities.

[jason0012]

I am going to go out on a limb here and assume you are forming thin steel into a complex shape, like a leaf or flower. Effectively such a die is bending and not forging. In such an application an aluminum die could conceivably withstand several parts- may hold up just fine (???) depending on how extreme the forming, hardness and thickness of material and level of detail required. If you are actually needing steel to flow, that would likely be a different story. Give it a shot and see how it goes. 

[swedefiddle]

Good Morning JasonW,

I would think that by the time you hand made a top and bottom Die, your product could be finished, by hand. Thinking out loud, never hurt though!!

Neil