casting

[Drenched_in_flame]

how does casting a sword make it weaker than forging?

[matt87]

It's very difficult to cast steel, or even to melt it properly. It is though possible to cast bronze or copper swords (I have been lucky enough to watch it done using very simple tools).

[John B]

Forging gives a tighter / refined grain structure than casting. Usually bronzes and copper do not willingly give themselves to being forged.

[Fruityloops31]

I'm a bit confused on this matter, when steel is melted does it not it revert back to iron?
how would this process be done. I am familiar with lost wax castings, but not with steel.

(jodysamson.com/axes.htm)
these are some beautiful axes and i would like to try casting steel into forms like these!

[Johannes]

casting a sword...
take anny object in cast steel that is thinner than 1 cm, hit it with an hammer and it(l break... cast isnt flexible like forged, a zword need to be a bit flexible and hard at the same time...

[Don A]

how does casting a sword make it weaker than forging?

Same reason 3/4" particle board is weaker than 3/4" plywood.

Refined, directional grain structure.

[matt87]

Originally Posted by Fruityloops31

I'm a bit confused on this matter, when steel is melted does it not it revert back to iron?
how would this process be done. I am familiar with lost wax castings, but not with steel.

(jodysamson.com/axes.htm)
these are some beautiful axes and i would like to try casting steel into forms like these!

For all intents and purposes, you can't cast steel outside of a massive, expensive foundry setup. Even if you did cast something out of a high-carbon steel (feasible but not easy) it would be very brittle. The higher the carbon content, the lower the melting point. Ergo 'cast iron' (2.2-4% carbon) is easiest to cast of the iron alloys. High carbon steels are next (.6-2.2% carbon) and then the medium steels (.3-.6) and the mild steels (.2-.3). The higher the level of carbon in an iron alloy, the brittler it is. You can anneal a casting to make it tougher (less brittle) but it's not really worthwhile for your application.

It's entirely possible to cast 'cast iron' (2.2-4% carbon) in your back garden, as well as various non-ferrous metals such as brass, bronze, copper, lead, tin etc. Aluminium is a good candidate for a wall-hanger/display item since it melts relatively easily, it's got a low density, is readily available as scrap and is shiny. There are many safety aspects involved -- one drop of water in a crucible and you've got a molten metal explosion.

[ThomasPowers]

To cast high carbon steels you would probably want to go with a vacuum melt system to prevent contamination of the metal as various gasses tend to be absorbed by the molten steel and various alloying components can be "burnt off".

You also need to be carefull of alloy element segregation when the melt is cooling; (take a look at zone refining for an extreme case).

Cooling from a melt is generally done slowly and slow cooling makes for a larger grain size that is weaker. There are methods to get around all of this but they tend to be high tech and expensive.

Probably a lot more efficient to find a place that does such castings and work with them to create the molds and cast the pieces.

Remember that to do a one-off you should expect it to cost several times what even a low number production casting piece costs. So *MUCH* *MUCH* *MUCH* chaper to buy one of his than to try to replicate one by casting. Me I'd forge my own.

If you look at historical methods of casting steel, they would cast an in got and then refine the grain by substantial forging---think steam hammers---and then use the hammered out stock to make things from. They did not cast to shape.

[Aeneas]

Originally Posted by Don A

Same reason 3/4" particle board is weaker than 3/4" plywood.

Refined, directional grain structure.

OOOHHH ... good analogy
well done.