The document discusses 4340 steel, detailing its composition, applications, and mechanical properties. It is primarily composed of iron, nickel, chromium, and other elements, making it suitable for aircraft landing gear due to its strength and toughness. The document also addresses manufacturing limitations and competitive materials.

1. Name:Chandraneel Pal
Rollno:1802233
Topic:4340 Steel
Submitted to:
Profssore Dinesh Kumar
Rathore

2. Application & Composition of 4340 Steel
Composition Content%
Iron 95.71
Nickel 1.83
Chromium 0.81
Manganese 0.70
Carbon 0.40
Molybdenum 0.25
Silicon 0.23
Sulphur 0.04
Phosphorus 0.03
Landing gear of aircarfts
Imagesource:https://www.google.com/url?sa
=i&source=images&cd=&ved=2ahUKEwidoP3rw-
rlAhV98XMBHdAcBNEQjRx6BAgBEAQ&url=https%3A%2F%2Fw
ww.ggbearings.com%2Fen%2Fsolutions-bearings%2Freduce-
size-weight%2Faerospace%2Flanding-
gears&psig=AOvVaw2skCeQ7tOBIDvs0OOBYc7P&ust=1573849
323815611

3. Microstructure of 4340 Steel
• Forging
• Heat Treatment
• Annealing
• Normalising
• Hardening
• Tempering
Austenite
Bainite
Austenite+Martensite
Pearlite+Pro Eutectoid Ferrite
Onset of Martensitic Transformation

4. Mechanical Properties
Properties Value
Tensile strength 745 MPa
Yield strength 470 MPa
Bulk modulus (typical for steel) 140 GPa
Shear modulus (typical for steel) 80 GPa
Elastic modulus 190-210 GPa
Poisson's ratio 0.27-0.30
Elongation at break 22%
Reduction of area 50%
Hardness, Brinell 217
Hardness, Vickers (converted from
Brinell hardness)
228

5. FAQ'S
• What does 4340 stand
for?
• Limitations of 4340
steel
• How to overcome the
limitations in
manufacturing?
• Any competetive
material?
Image courtsey:http://www.astmsteel.com/steel-
knowledge/steel-grade-4130-vs-4340/