here is the info on it
AISI 4340 FORGED STEEL CRANKSHAFTS
CAT forged 4340 steel crankshafts have been tested and proven to excel in engines producing 1,000 horsepower and 10,000 RPM. The premium 4340 aircraft quality steel with vacuum degassed forging process creates a clean and pure crankshaft. The state-of-the-art CNC machine centers provide superior tolerance.
CAT 4340 crankshafts incorporate these features:
- Computer designed counterweight to reduce main bearing loads.
- CNC machined to provide superior tolerance and journals micro polished to 5 RMS.
- Generous 0.125" journal radii to disperse stress under high loads.
- Each crankshaft has been visually inspected, X-rayed, magnafluxed, and ultrasonic tested to ensure perfection.
- All cranks are heavier at counter weight for easier balancing with various applications.
- Journal surfaces are treated with plasma gas nitrite to HRC60 hardness for superior wear resistance.