4340 Annealed Plate

*This product is no longer kept in stock, but can be ordered per customer request

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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.

Chemical Composition

Heat Analysis - ranges and limits %

C

.38/.43

Mn

.60/.80

P

.035 Max

S

.040 Max

Ni

1.65/2.00

Cr

.70/.90

Mo

.20/.30

Processing Temperatures

Typical

Forge

2200°F Max

Normalize

1550/1650°F

Case Harden

1475/1550°F

Anneal 

1475/1575°F Max

Temper

1200°F & 400°F