Forged or billet? (1 Viewer)

flapjack

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Nitro Member
I was wondering. I have heard of billet blocks and forged blocks. I understand the difference between the two -- (a) in the forged case, the raw chunk of metal is heated and pressed into a rough form and then machined down; (b) in the billet case, the final form is machined straight from the raw chunk of metal.

To confuse matters even more, the raw chunk of metal that one starts with is called a billet, and in reality, a billet itself is itself a forging made right at the forgery.

But I shall stick to the "definitions" (a) and (b) of forged and billet.

From what I have seen, the TFX and BAE blocks are forged (BAE even states clearly that their blocks are forged). Yet every one talks about a billet block.

Why?
 
To confuse matters even more, the raw chunk of metal that one starts with is called a billet, and in reality, a billet itself is itself a forging made right at the forgery.
Just a bit of clarification, a billet can either be forged, extruded or as poured. Most billet parts I've seen are from the as-poured and extruded variety, no forging performed.

Billets are stronger than castings because of their aligned grain-flow, forged billets are even stronger because they have had the grain-flow aligned and compressed.

As for the different terminology used, right now billet is a popular phrase that is quite often misunderstood, kind of like your statement that I quoted above.
 
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A forged billet is one solid chunk of material (aluminum, steel, etc.) that is heated and pressed into its initial rough shape and then finish machined from there.
 
All of the fuel teams use BILLET blocks as required by NHRA rules.

Forged can be stronger than some billet pieces due to the alignment of grain.BUT not all materials are are forgable.the better billet materials that are used in the billet blocks is far more superrior to the forgeable material.
 
Just a bit of clarification, a billet can either be forged, extruded or as poured. Most billet parts I've seen are from the as-poured and extruded variety, no forging performed.

Billets are stronger than castings because of their aligned grain-flow, forged billets are even stronger because they have had the grain-flow aligned and compressed.

As for the different terminology used, right now billet is a popular phrase that is quite often misunderstood, kind of like your statement that I quoted above.

Did you mean "extruded billets are strong than castings, ...."?

And yes, I am confused. People have been throwing phrase around and I've never been given an adequate explanation.

My guess is that the NHRA requires is an engine block that starts life as a forged billet and is machined down.
 
OK, here goes...

A billet is a solid chunk of metal. It can be poured, extruded, or forged.

A top fuel block starts its life as a billet and is machined from there.

I finally realized my confusion stems from this: NHRA requires a billet block.
But BAE claims their block is forged.

So I assume that the billet as required by NHRA is really a billet that was
created by forging.

Machining from billets is better than casting because the block is cast into shape so it does not have grain alignment/high density.

I ask for forgiveness in my pedantic questions. I was "raised" as a
mathematician and have never gotten over attention to minutea.
 

This I already knew. I am down to the point where I know one starts with a billet. Is that billet further forged before machining, or is that billet just machined straight-away? I am fairly certain that with cranks one just starts with the billet and machines as the material is not forgeable.

If you look at the oil galleys in a TFX block, they aren't machined; they look like a an unmachined portion of a forging.
 
Good cranks start with a billet and are beaten into their basic shape by forging with a die and then machined to finish size.
 
TFX and BAE blocks are rolled aluminum billets that have been forged prior to any machining.

Heads are made from rolled aluminum billets.

Cranks are billet, but the materials vary and manufacturers are constantly experimenting with the grade of material and heat treatments. Forged cranks have better grain structure from forging, but have a lot of stress from the twisting and straitening that needs to be done after forging. I have seen them work in alcohol and limited nitro applications with shorter strokes, but seldom last in a big show, long stroke nitro car.

Heat treating aligns the grain structure in all materials and allows the manufacturer to adjust the materials to meet their requirements. Some materials are cold stabilized as their heat treatment. Some parts need tensile strength, some need flexibility, some need impact resistance and others need a little of everything. At some time in their creation, all metal materials are ran through a heat treating cycle, even if it is to normalize them.
 
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