Description
High Tensile Steel, AISI 4340, 6582, 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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