Alloy Steel 4130
A common general purpose grade of medium carbon, Cr-Mo steel. Flexibility afforded by heat treatment options allows it to attain a range of toughness and strength values. Good hardenability, strength, wear resistance, toughness, and ductility.
Alloy Steel 4140
Normalized: heated to 815°C, air cooled. Medium-carbon steel with high hardenability and good fatigue, abrasion and impact resistance.
Alloy Steel 4145
Oil quenched. Forging temp.: 1205°C (2200°F) max. Annealing temp.: 790 - 845°C. Hardening temp.: 815 - 845°C. Tempered to desired hardness.
Alloy Steel 4330
Alloys for general structural use.
Alloy Steel 4340
AISI 4340 has a favorable response to heat treatment (usually oil quenching followed by tempering) and exhibits a good combination of ductility and strength when treated thusly. Uses include piston pins, bearings, ordnance, gears, dies, and pressure vessels.
Alloy Steel 8630
Heated to 870°C, air cooled.