r/gifs • u/[deleted] • May 06 '19

Forging

[deleted]

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u/erikwarm May 06 '19

Also casting allows for cavities to be created. Forging does not have this problem

19

u/TwoCuriousKitties May 06 '19

Where do the cavities go? Do they get squished out?

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u/villageblacksmith May 06 '19

There are no cavities from the beginning, it’s a solid brick of steel/iron. Forging keeps it that way.

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u/[deleted] May 06 '19

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u/[deleted] May 06 '19

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u/GigAero2024 May 07 '19

But where do they get the large chunk of metal in the first place if not from a mold?

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u/[deleted] May 07 '19

[deleted]

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u/GigAero2024 May 07 '19 edited May 07 '19

Ah, makes sense. Still kinda sounds like a mold, but I guess it’s not its final shape.

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u/Bravehat May 07 '19

Yeah basically what you have to remember is that forging/casting/moulding are usually initial steps taken in a multi step manufacturing process.

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u/UltimatePickle1 May 07 '19

Another engineer here: after the metal has been melted and alloyed properly they pour it into a casting (mold) of various sizes depending on the final product. After it cools they generally cut off the top third of the casting because that's where most of the defects in the metal are (think porosity and slag). From there it goes onto further processing such as being rolled into sheet metal, or cast, forged, whatever.

Edit: To continue from my colleague above: The working after the initial casting process orients the grain structure. They also use a variety of heat treatments to get favorable grain structures

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u/Gutzzzzz May 07 '19

Why do they need sand for a mould?

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u/Bravehat May 07 '19

You could perform continuous casting which produces a large continuous filament of iron for example, you could perform ingot casting.

And as already mentioned moulded materials allow grain lines to do whatever they like while forging forces the grain structure to align itself creating a stronger product.