Cast, Forged, Billet
 

I've seen alot of talk on here about cast steel and factory cast iron cranks, which is stronger, etc. I found some information so I thought I would share. I'm also posting a link to a really good article on the the difference's between the 3 types of crankshafts. This may help others decide what type of crank they need for what they are doing.

Link to the whole article: http://www.popularhotrodding.com/tec...ech/index.html

Hierarchy Of Metals

Since the American Society for Metals allows for some leeway within each grade of metal, the tensile strength ratings listed in this chart and elsewhere in the story are approximate, not exact figures. Nevertheless, they do adequately allow comparison among the strengths of different metal grades. While these represent just a small portion of all the steel alloys established by the ASM, they are the ones most common in automotive applications. Here's a quick rundown:

MATERIAL: TENSILE STRENGTH: RATING:

Cast iron 70,000-80,000 psi OE engines
Nodular iron 95,000 psi OE engines
Cast steel 105,000 psi strongest of the cast cranks
1010/1045/1053 100,000-110,000 psi high-carbon factory-grade forging
5140 steel 115,000 psi sportsman-grade forging
4130 steel 120,000-125,000 psi premium alloy
4340 steel 140,000-145,000 psi strongest alloy for cranks and rods