4340 Heat Treated
PACIFIC 4340 is available in two conditions: heat treated (quenched and tempered) to high strength or annealed for ease of machining and subsequent heat treatment. It is a nickel-chromium-molybdenum medium carbon alloy steel with deep hardenability. It can be through hardened in large sections. When properly hardened, 4340 exhibits a good combination of strength, ductility and toughness; this is the material to which other ultra-strength steels are compared. PACIFIC 4340 Heat Treated bars are hardened to 285/331 HB and meet ASTM A 434, Class BD. 4340 is weldable but only with proper precautions; because of its high hardenability, it requires both preheat and post heat in virtually all welding applications. It can be induction hardened or nitrided after quenching and tempering.
Heat Analysis - ranges and limits %
Approximate - not for specification
Over 2-1/2" thru 4"
Over 4" thru 7"
Over 7" thru 9-1/2"
1200°F & 400°F
Shapes and Conditions Available
Hot Rolled Annealed Rounds through 3" Diameter
Rough Turned Oversize Annealed Rounds from 3-1/4" through 17-1/2" Diameter
Rough Turned Oversize Heat Treated Rounds from 3-5/8" through 10" Diameter