See a crankshaft created from a raw steel billet

Dumb question.....why can't that billet be cast into the rough enough shape that most of that machine work is not necessary?? especially for automotive applications.....
 
Dumb question.....why can't that billet be cast into the rough enough shape that most of that machine work is not necessary?? especially for automotive applications.....

Then it would be a cast crank not billet.

The Difference Between Casting & Forging

Casting is the process where metal is heated until molten. While in the molten or liquid state it is poured into a mold or vessel to create a desired shape.

Forging is the application of thermal and mechanical energy to steel billets or ingots to cause the material to change shape while in a solid state.

Why use castings?

We use castings for a wide range of wearparts and components that are too large, complicated, intricate or otherwise unsuitable for the forging process. We can forge parts up to 50kgs but the sheer energy required to forge larger items make casting a much more viable alternative.

We currently cast mining and earthmoving components to 580 kg. We can cast up to 3000 kg if required. Manganese work hardening screens are one of our specialities. We have found that by carefully choosing alloys and applying proven methods of heat treatment, we can produce castings of high quality, strength and wearability. The casting process better lends itself to making parts where internal cavities are required.

The advantages of casting include:

No real upper size limit in casting weight
Large range of alloy choices
As forgings remain solid, custom alloys are far more difficult to get into production whereas with casting, alloys including Chrome, Nickel and Moly can be added at the molten stage.
Tooling is often less expensive than forge dies
Smaller production "runs" required
Complicated/complex parts are no problem
For general GET as well as large and complex components - casting is a fantastic method of manufacture.


Why use forgings?

Forging offers uniformity of composition and structure. Forging results in metallurgical recrystalisation and grain
refinement as a result of the thermal cycle and deformation process. This strengthens the resulting steel product particularly in terms of impact and shear strength.

Forged steel is generally stronger and more reliable than castings and plate steel due to the fact that the grain flows of the steel are altered, conforming to the shape of the part.

The advantages of forging include:

Generally tougher than alternatives
Will handle impact better than castings
The nature of forging excludes the occurence of porosity, shrinkage, cavities and cold pour issues.
The tight grain structure of forgings making it mechanically strong. There is less need for expensive alloys to attain high strength components.
The tight grain structure offers great wear resistance without the need to make products "superhard" We have found that, on a blank HRC 38-42 forged grinder insert wear/wash is about the same as a high alloy HRC 46-50 cast grinder insert. The difference being a HRC 46-50 casting does not have the ductility to handle high impact grinding.
 
That video is absolutely amazing to me! Just Wow. But I was really surprised at the size of some of those shavings. They were removing giant chunks of metal at a time. And how much of the process was done dry.
 
Fascinating video and it makes me wanna go cut chips. But a lot of things don't ring true there. I saw multiple setups which surprised me. What is that beautiful crank for? How many actual hours were involved in our seventeen minute highlight? How much was the final cost?

Did you notice the offset siamesed rod journals in the one shot? Interesting stuff there.

Did the CNC produce a final dimensioned bearing surface or did it still go to a grinder for final surface??

Very interesting....
 
Some years ago I did a 2 month stint as a shipyard electrician, and saw some amaZZZZZing sites.....one of which was an old German RORO stands for Roll on/Roll off for freight, 800' long, and so it was bought by the US Marines for the islamic wars....

ONE thing that amazed me was this odd count single engine, single prop design....that engine had maybe 5/7? cylinders and was larger than ~40' tall, like to see them work on THAT crankshaft.....it was said the engine could be repaired down to cylinder work while under way......they stuck to the story, but I hardly a marine mechanic, so just smiled and I shut up.....
wonder that it run at all, as I was a little kid on a Lake Erie tour with family from Cleveland to Detroit, and interested in the engine room on that boat, they left the door open and so me/cousin got chased outta there, I just remember seeing those huge valves opening and closing from up top, and the revolutions of the engine was so slo, I could watch it turn over.....KRAZY....been a motor head ever since.....


:shocking::p:beer:
 
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