4340 Steel Bar

Size ranging from .250" to 15"

The 4340-alloy steel bar is composed of a nick, chromium, molybdenum alloy. It’s recognized for its durability and ability to achieve great strength when heat-treated. It also offers excellent resistance against fatigue and wear, as well as good atmospheric corrosion resistance.

4340 steel has excellent strength-to-weight ratio, making it ideal for parts that require high strength and resilience to wear and tear. It’s also known for its exceptional toughness and ability to withstand extreme conditions, which makes it suitable for use in high-stress environments.


4340 steel bars are a versatile and robust material, used in various industries due to their superior strength and toughness. Here are the main applications:

  • Aerospace: Used in landing gear and aircraft structural parts for their high strength-to-weight ratio.
  • Automotive: Ideal for high-stress parts in performance vehicles, such as axles, crankshafts, and gears.
  • Energy: Utilized in parts of turbines and generators for their high fatigue resistance.
  • Industrial Equipment: Found in heavy-duty shafts, gears, and fasteners where maximum strength is needed.
  • Defense: Employed in the manufacture of armored vehicles and military equipment due to their impact resistance.

Requirement Specifications we can meet:

  • ASTM A29
  • ASTM A576
  • JDM QL-2 certified

Shapes Available

  • Rounds
  • Square
  • Hexagon
  • Rounded Cornered Square
  • Flats
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Hot Rolled Steel Properties

Chemical Properties
Carbon 00.38 – 0.43
Manganese 0.60 – 0.80
Phosporus (max) 0.035
Sulfur (max) 0.040
Silicon 0.15 – 0.35
Nickel 1.65 – 2.00
Chromium 0.70 – 0.90
Molybdenum 0.20 – 0.30

If your application requires specific mechanical properties, please inquire with our sales team.

Process Services

King Steel offers a variety of value-added services to improve your workflow and quality control. Our processing capabilities include:

  • Turn and Polish
  • Cold Drawing
  • Annealing
  • Chamfering
  • Grinding
  • Quench and Temper
  • Heat Treated
  • Machine Straightening
  • Precision Saw Cutting
  • Custom Shapes
  • Shot Blast
  • Eddy Current Testing
  • Turn, Ground & Polished
  • Cold Drawn, & Polished
  • Straighten & Cut
  • Ultrasonic Testing
  • Pickle & Oil
  • Stress Relieve
  • Normalize
  • Case Hardening

Learn more about our processing capabilities.

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