AISI 4340 steel
Key benefits include:
high durability;
ease of processing;
possibility of additional hardening (cementing, nitriding) ;
Corrosion resistance;
deformation resistance;
good plasticity.
Features and Applications
The main forms of release are: steel circle 4340, bar, rebar, wire. Depending on the manufacturing technology, there are forged wheels 4340, cold-rolled and hot-rolled
The main direction of use is the production of elements, parts, structures with high requirements for rigidity and strength, as well as with minimal wear. Alloys of this grade are used in mechanical engineering for the production of parts for transmission boxes and systems, for the manufacture of shafts and universal joints, gearboxes.
In addition, AISI 4340 alloys and their closest analogues are used for the production of aircraft landing gear. The world’s largest aircraft manufacturers have appreciated the reliability and durability of this series alloys in those situations where it is required to ensure maximum safety under fairly severe regular loads.
AISI 4340 steel chemical composition
Standard | Grade | C | Mn | P | S | Si | Ni | Cr | Mo |
ASTM A29 | 4340 | 0.38-0.43 | 0.60-0.80 | 0.035 | 0.040 | 0.15-0.35 | 1.65-2.00 | 0.70-0.90 | 0.20-0.30 |
AISI 4340 mechanical properties
Mechanical Properties ( Heat Treated Condition ) | Condition | Ruling section | Tensile Strength MPa
| Yield Strength | Elong. | Izod Impact | Brinell |
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 | 123 0-1380 | 1080 | 10 | 24 | 363-429 | |
Z | 30 | 1555- | 1125 | 5 | 10 | 444- | |
AISI 4340 steel circle delivery forms
Steel circles | |
| Steel grades | Dimensions supplied (mm) |
| AISI 4340 steel circle | 50 – 485 |




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