AISI 4340 Alloy Steel

WALDUN is one of the best AISI4340 alloy steel manufacturers and suppliers in China, you can get ound rods,square/flat bars,rollers,shafts,blocks and forging pieces with competitive price.

AISI4340 Alloy steel is a general nickel-molybdenum alloy steel as per American standard which has high strength,toughness and excellent hardenability. AISI4340 is usually supplied under quenched and tempered condition at the hardness of 24 – 29HRc.

Typical applications are for structural use, such as aircraft landing gear, power transmission gears and shafts and other structural parts.

AISI 4340 Equivalent Grade Chemical Composition

National Standard	Grade	C%	Si%	Mn%	Cr%	Mo%	Ni%	P%	S%
DIN	34CrNiMo6 (1.6582)	0.30-0.38	≤0.4	0.5-0.8	0.9-1.2	0.15-0.3	1.3-1.7	≤0.025	≤0.035
SAE/AISI	4340	0.38-0.43	0.15-0.35	0.6-0.8	0.7-0.9	0.2-0.3	1.65-2.0	≤0.035	≤0.04
JIS	SNCM447	0.36-0.43	0.15-0.35	0.6-0.9	0.6-1.0	0.15-0.3	1.6-2.0	≤0.035	≤0.04
GB	40CrNiMoA	0.37-0.44	0.17-0.37	0.5-0.8	0.6-0.9	0.15-0.25	1.25-1.65	≤0.025	≤0.025
BS	EN24	0.36-0.43	0.1-0.35	0.45-0.7	1.0-1.4	0.2-0.35	1.3-1.7	≤0.035	≤0.035

AISI 4340 Alloy Steel Size & Tolerance & Process

Shape	Size(mm)	Process	Tolerance	Length(mm)
Round	Φ6-Φ50	Cold Drawn	H11	3000-5800
Round	Φ40-Φ300	Hot Rolled	-0/+3mm	3000-10000
Round	Φ120-Φ1000	Hot Forged	-0/+3mm	3000-10000
Flat/Square/Block	Thickness:120-800 Width:120-1500	Hot Forged	-0/+3mm	500-6000

AISI 4340 Heat Treatment

Normalizing For AISI4340
1.Nominal normalizing temperature:840-900°C
2.Hold the temperature for several hours
3.Cooling in the air

Annealing For AISI4340
1.Nominal Annealing temperature:800-860°C
2.Cool slowly in the furance
3.Maximum Brinell hardness of 270

Hardening and Tempering(QT) For AISI4340
1.Nominal Hardening temperature:830-865°C
2.Hold at this temperature then quench in oil
3.Tempering as soon as possible when the temperature low to ambient temperature
4.Heat the steel carefully to a suitable temperature selected by reference to a tempering chart or table
5.The usual tempering temperature is 600°C which depending on the actual requirements
6..keep the material out of the furnace ,then cool in the air

Mechanical Property( for reference only)
1.Tensile strength: 1020MPa
2.Yield point: 945MPa
3.Percentage reduction of area after fracture: 55%
4.Elongation after fracture: 13%
5.Impact test (+20°C): Transverse – 27~32J; Longitud – 45~50J

AISI4340 Alloy Steel Delivery Condition

1.Shape:Round/Square / Flat/Shafts/Rollers/Blocks
2.Surface condition:Black surface/Bright surface
3.Heat Treatment:Normalized/Annealed/QT
4.Straightness:Max 3mm/m(Enhanced straightness may be available on request)
5.Length:3000-5800mm suitable for 20″container. above 6000mm,suitable for 40″ container
6.Grain Size: 5-8 acc to ASTM E112-96
7.Typcial Hardness:HRC28-32
8.Ultrasonic Standard: Sep1921/ASTM A388/EN 10228-3
9.Non Metallic Inclusion: 2 max acc to ASTM E45 /K4≤20 acc to DIN 50602
10.Forging Ratio: minimum 4 : 1
11.Marking: Grade/Weight/Length/Size/Heat Number

AISI4340 Alloy Steel Quality Certification

A material test report(Inspection Certificate EN 10204 3.1) will be provided, documenting the following:
1.Chemical analysis
2.Mechanical properties
3.Surface hardness
4.Non Metallic Inclusion
5.Heat Treatment Process
6.Grain size
7.Forging ratio
8.NDE test method/criteria