lost wax investment casting for steel?

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savagesword

savagesword

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I've been trying to find a service provider to do small runs of lost wax investment casting in steel. All the providers I contacted have not been interested in small runs or one-off castings.

Anyone know of a company?

Thanks!
 
I doubt you will find anyone willing to do less than a thousand pieces of small items. The cost of setting up the molds is a lot more than it is for casting silver/brass,gold. You will pay less for a machine shop to do the items by CNC mill from bars of steel.
 
I was thinking they would do it much like bronze investment casting is done....where the process starts with a wax master, coated with investment material (silica slurry), heat it all up to dump out the melted wax (left with a void)...then fill the void with molten steel... crack the shell off, done. This process doesn't require the creation of reusable molds....just a process to create wax masters (that requires a mold).
 
Do an experiment - Make a simple mold of a bolt in wax, invest it, melt some steel, and pour it in the cavity. Give it a try and let us know how it worked out for you. :)


Unfortunately, it isn't that simple with steel. Brass/bronze melt about 1000 degrees cooler than molten steel......and there are all sorts of other issues to deal with that don't happen at 1600/1700F.
 
What is the cold material being placed around the wax model to create the mold? Surely not plaster as with making fine jewelry parts. Wouldn't that amount of molten steel crack a plaster mold?
 
???
Maybe I'm missing something?:confused:

Investment casting steel is done ALL THE TIME!
There are half a dozen foundries within 40 miles of me that do it.

I've had as few as 1 part cast in steel by an art foudry in Oxnard (I supplied the finished wax) It was something like $80.
It's been a few years, but I had a short run of parts (12 sets of parts, totally maybe 5 parts/set) done in 4130 once (I supplied the finished waxes).

(It will cost much more if they're making your waxes)

It's sometimes called shell casting, but its just a lost wax casting technique . They sprue up your wax(s) and dip them in various refractories and let them dry.
Takes about a week. They burn the wax out and make the pour, chisel off the refectory and cut your part off the sprue.

If you Google "steel shell casting" or "steel investment casting", you'll find a bunch of foundries doing it.
 
I am in agreement that it is done...just not the same as crystobalite molds used in brass/bronze casting.....and a lot more expensive. That is why I said it may be cheaper to have a small part CNC milled.
 
Stacy,
I'm not trying to be argumentative. I certainly hold you and your opinion in high esteem.
This is one of those extremely rare times I'll have to respectfully disagree. :o

The last time I had steel done, I got a pretty detailed tour of the facility, which involved a walkthrough from the waxing to the "stuccoing" of the trees to burn out, pouring, de-spruing, etc.

All I know about the slurry is it contains silica and the tree is dipped several times over several days into slurries of different consistencies.

I'm absolutely certain they were doing the steel the same way as their bronze because my parts were treed up and slurry-coated right next to art bronzes. Whether there were different additives in the slurry for steel vs. bronze, I don't know.
At the time, cost was the same for steel as for bronze for my little part. If it was a bigger project, the bronze would be more expensive because of the material cost (I quoted it).
I had a choice of several steel alloys including a few stainless steels, I don't remember them all, it's been a few years.
This particular foundry (the one in Oxnard, CA I mentioned) had been doing all of the steel sword hilt castings for Albion when they did my little one-of project.

I totally agree, if you're setting up with "real" (permanent) tooling, molds cost huge, huge amounts of money. Impossible to justify in most situations.
But investment casting is cheap, and it's still used extensively to cast steel and titanium aircraft parts.

If it's a part like a detailed sword pommel or other fitting, investment casting will almost always be cheaper than CNC because of the extensive programming and fixturing required before you can make even one part on the CNC. It'll be hours doing the CAD model. Then, doing compound curves requires time-intensive 3D milling (on a 3 axis) or the use of a 5th axis mill, which is big money per hour. Plus, the 5th axis guys are going to want a reasonable run to justify the more complicated programming and the time taken away from the regular (usually DOD) jobs.

BTW, if the OP is thinking of casting a blade, I'd advise against it. It's done sometimes, but it's not nearly an optimum process for that.:)
 
I've have some metal parts grown via selective laser sintering out of a bronze stainless powder mix. This was about six or eight years ago. I've heard the process has improved and various grades of steel and I think even titanium are now available. Something to consider for certain wonky parts if you have a CAD model.
 
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