AISI 4140

AISI 4140

Alloy steels are designated by AISI four-digit numbers and comprise different kinds of steels, each with a composition which exceeds the limitations of B, C, Mn, Mo, Ni, Si, Cr, and Va set for carbon steels. AISI 4140 alloy steel is a chromium-, molybdenum-, and manganese-containing low alloy steel. It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength.

Chemical Composition


Element Content(%)
Chromium, Cr 0.80 - 1.10
Manganese, Mn 0.75 - 1.0
Carbon, C 0.380 - 0.430
Silicon, Si 0.15 - 0.30
Molybdenum, Mo 0.15 - 0.25
Sulfur, S 0.040
Phosphorous, P 0.035
Iron, Fe Balance

Mechanical Properties


Properties Metric Imperial
Tensile strength 655 MPa 95000 psi
Yield strength 415 MPa 60200 psi
Bulk modulus (typical for steel) 140 GPa 20300 ksi
Shear modulus (typical for steel) 80 GPa 11600 ksi
Elastic modulus 190-210 GPa 27557-30458 ksi
Poisson's ratio 0.27-0.30 0.27-0.30
Elongation at break (in 50 mm) 25.70% 25.70%
Hardness, Brinell 197 197
Hardness, Knoop (converted from Brinell hardness) 219 219
Hardness, Rockwell B (converted from Brinell hardness) 92 92
Hardness, Rockwell C (converted from Brinell hardness. Value below normal HRC range, for comparison purposes only) 13 13
Hardness, Vickers (converted from Brinell hardness) 207 207
Machinability (based on AISI 1212 as 100 machinability) 65 65

Sheets / Plates

Production Route Hot Rolled, Cold Rolled
Material Standard AISI, ASTM, ASME, DIN, BS, EN, ISO, JIS, GOST, SAE, IS & Custom Chemistry
Size Width from 100mm to 3000mm ; Length from 500mm to 12000mm
Thickness 0.1mm to 400mm
Delivery Condition As Rolled, Annealed, Quenched and Tempered, Normalized
Surface Finish Plain, Brushed, Cladded

AISI 4140 Equivalent Grade / Specifications

  • AMS 6349
  • ASTM A193 (B7, B7M)
  • ASTM A506 (4140)
  • ASTM A752 (4140)
  • AMS 6381
  • ASTM A194 (7, 7M)
  • ASTM A513
  • ASTM A829
  • AMS 6382
  • ASTM A29 (4140)
  • ASTM A513 (4140)
  • SAE J1397 (4140)
  • AMS 6390
  • ASTM A320 (L7, L7M, L7D)
  • ASTM A519 (4140)
  • SAE J404 (4140)
  • AMS 6395
  • ASTM A322 (4140)
  • ASTM A646 (4140)
  • SAE J412 (4140)
  • AMS 6529
  • ASTM A331 (4140)
  • ASTM A711

AISI 4140 Applications

  1. Structures in Buildings, bridges, railway stations
  2. Fabrication of pipeline components & Industrial equipment
  3. Construction of automotive bodies, warehouses, shipping containers
  4. Commercial appliances, etc.