AIS4340 is a high-strength nickel-chromium-molybdenum alloy steel with superior hardenability and outstanding comprehensive mechanical properties. After quenching and tempering treatment, it delivers ultra-high tensile strength, excellent toughness, impact resistance and fatigue performance. It maintains stable structural strength under heavy load and complex stress conditions, and is widely used in aerospace parts, high-load shafts, gears, heavy machinery components and high-strength fasteners.

Advantage

1.Excellent deep hardenability, uniform internal and external hardness for large section parts 2.Ultra-high strength and toughness combination, far better than ordinary alloy steel 3.Outstanding fatigue resistance and impact toughness for severe dynamic load environments 4.Stable heat treatment performance and reliable dimensional stability after processing

Ingredient

• C
• 0.38 ~ 0.43
• Ni
• 1.65 ~ 2.00
• Cr
• 0.70 ~ 0.90
• Mo
• 0.20 ~ 0.30
• Mn
• 0.60 ~ 0.85
• Si
• 0.15 ~ 0.35
• P
• ≤0.035
• S
• ≤0.040
• Fe
• Balance

• Board
• Stick
• Pipe

Title

4340 Board

Size

0.5mm – 100mm

Length

1000mm – 6000mm (customizable)

Production

Hot rolled + Annealed

Surface

Pickled / 2B / Polished

Processing

Hot rolled + Annealed

Standard

• USA
• ASTM A829 / AISI 4340
• China
• GB/T 3274‑2017、GB/T 11251‑2021

Mechanics

• STATE
• RP
• YIELD
• EXTEND
• SHRINK
• HARDNESS
• IMPACT
• Annealed
• ≥1080 MPa
• ≥980 MPa
• ≥12 %
• ≥45 %
• ≤330 HBW
• ≥25 J
• Annealed
• ≥1040 MPa
• ≥940 MPa
• ≥12 %
• ≥45 %
• ≤330 HBW
• ≥25 J

• STATE
• Annealed
• RP
• ≥1080 MPa
• YIELD
• ≥980 MPa
• EXTEND
• ≥12 %
• SHRINK
• ≥45 %
• HARDNESS
• ≤330 HBW
• IMPACT
• ≥25 J
• STATE
• Annealed
• RP
• ≥1040 MPa
• YIELD
• ≥940 MPa
• EXTEND
• ≥12 %
• SHRINK
• ≥45 %
• HARDNESS
• ≤330 HBW
• IMPACT
• ≥25 J

Title

4340 Stick

Size

8mm – 300mm

Length

1000mm – 6000mm (customizable)

Production

Hot rolled + Annealed

Surface

Black / Peeled / Polished

Processing

Hot rolled + Annealed

Standard

• USA
• ASTM A322 / AISI 4340
• China
• GB/T 3077‑2015、GB/T 4356‑2021

Mechanics

• STATE
• RP
• YIELD
• EXTEND
• SHRINK
• HARDNESS
• IMPACT
• Annealed
• ≥1080 MPa
• ≥980 MPa
• ≥12 %
• ≥45 %
• ≤330 HBW
• ≥25 J
• Annealed
• ≥1040 MPa
• ≥940 MPa
• ≥12 %
• ≥45 %
• ≤330 HBW
• ≥25 J

• STATE
• Annealed
• RP
• ≥1080 MPa
• YIELD
• ≥980 MPa
• EXTEND
• ≥12 %
• SHRINK
• ≥45 %
• HARDNESS
• ≤330 HBW
• IMPACT
• ≥25 J
• STATE
• Annealed
• RP
• ≥1040 MPa
• YIELD
• ≥940 MPa
• EXTEND
• ≥12 %
• SHRINK
• ≥45 %
• HARDNESS
• ≤330 HBW
• IMPACT
• ≥25 J

Title

4340 Pipe

Size

6mm – 500mm OD, 1mm – 50mm WT

Length

1000mm – 12000mm (customizable)

Production

Hot finished + Annealed / Cold drawn + Annealed

Surface

Pickled / Bright annealed / Polished

Processing

Hot finished + Annealed / Cold drawn + Annealed

Standard

• USA
• ASTM A519 / AISI 4340
• CHINA
• GB/T 8162‑2018、GB/T 8163‑2018

Mechanics

• STATE
• RP
• YIELD
• EXTEND
• SHRINK
• HARDNESS
• IMPACT
• Annealed
• ≥1080 MPa
• ≥980 MPa
• ≥12 %
• ≥45 %
• ≤330 HBW
• ≥25 J
• Annealed
• ≥1040 MPa
• ≥940 MPa
• ≥12 %
• ≥45 %
• ≤330 HBW
• ≥25 J

• STATE
• Annealed
• RP
• ≥1080 MPa
• YIELD
• ≥980 MPa
• EXTEND
• ≥12 %
• SHRINK
• ≥45 %
• HARDNESS
• ≤330 HBW
• IMPACT
• ≥25 J
• STATE
• Annealed
• RP
• ≥1040 MPa
• YIELD
• ≥940 MPa
• EXTEND
• ≥12 %
• SHRINK
• ≥45 %
• HARDNESS
• ≤330 HBW
• IMPACT
• ≥25 J