4340 Alloy Steel

High Tensile Steel, AISI 4340, 6582, ASSAB 705, SNCM439, EN24

steel 4340 is a 1.8% nickel – chromium – molybdenum high hardenability high tensile steel – generally supplied hardened and tempered in the tensile range of 930 – 1080 Mpa (condition U) – (Rc 28 – 36)..

SKU: 4340 High Tensile Steel Category: Tags: , ,

Description

High Tensile Steel, AISI 4340, 6582, ASSAB 705, SNCM439, EN24

steel 4340 is a 1.8% nickel – chromium – molybdenum high hardenability high tensile steel – generally supplied hardened and tempered in the tensile range of 930 – 1080 Mpa (condition U) – (Rc 28 – 36)..Characterised by high strength and toughness in relatively large sections.

Pre hardened and tempered aisi4340 can be further surface hardened by flame or induction hardening and by nitriding.

1.6582 steel is used in most industry sectors for applications requiring higher tensile/yield strength than 1.7225 can provide.

Typical applications are: Heavy Duty Shafts, Gears, Axles, Spindles, Couplings, Pins etc.

DIN AISI JIS  4340 Steel Chemical Composition
40NiCr4Mo6 4340H SCM 439H C Si Mn P S Co Cr Mo Ni V W Cu
0.37 to 0.44 0.15 to 0.35 0.55 to 0.90 < 0.04 < 0.03 0.65 to 0.95 0.20 to 0.30 1.55 to 2.00 < 0.35

AISI 4340 Steel Equivalent and Specification

Country USA Britain Britain Japan
Standard ASTM A29 EN 10250 BS 970 JIS G4103
Grades 4340 36CrNiMo4/
1.6511
EN24/817M40 SNCM 439/SNCM8

AISI Alloy 4340 Steel Heat Treatment Properties

Mechannical Properties

(Heat Treated Condition )

Condition Ruling section
mm
Tensile Strength MPa Yield Strength
MPa
Elong.
%
Izod Impact
J
Brinell
Hardness
T 250 850-1000 635 13 40 248-302
T 150 850-1000 665 13 54 248-302
U 100 930-1080 740 12 47 269-331
V 63 1000-1150 835 12 47 293-352
W 30 1080-1230 925 11 41 311-375
X 30 1150-1300 1005 10 34 341-401
Y 30 1230-1380 1080 10 24 363-429
Z 30 1555- 1125 5 10 444-

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What kind of steel is 4340?
4340 is a nickel-chromium-molybdenum alloy steel known for its toughness and its ability to attain high strengths in the heat-treated condition. It has very good fatigue resistance.
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What is the difference between 4140 and 4340 steel?
The 4340 is stronger than the 41404140 that has been Hot Rolled, and Normalized has a tensil strength of 148,000 PSI, and a yeild of 95,000 PSI. 4340 that has been Hot Rolled, and Normalized has a tensil strength of 185,000 PSI, and a Yeild of 125,000.