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Material Specification

AISI 4340

AISI 4340 Fasteners

Nickel Chromium Molybdenum Steel AISI 4340

Buy AISI 4340 bolts, nuts and other fasteners from Exotic Alloy, a premier manufacturer & supplier of AISI 4340 bolting materials to ASTM A29, ASTM A322, SAE J404, and international high-tensile specifications. The highly engineered addition of nickel, chromium, and molybdenum delivers a formidable combination of deep hardenability, supreme toughness, and exceptional fatigue resistance, making it the ultimate choice for heavy cross-section parts.

Exotic Alloy fasteners offer AISI 4340 bolts and nuts with standard and custom manufacturing to your exact specification. We cover AISI 4340 hex bolts, studs, stud bolts, hex nuts, washers, threaded rod and other fastener in metric and inch sizes with coarse, fine and extra fine threads to ASME, UN, BS, ISO and DIN standards.

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AISI 4340 Bolting Products

AISI 4340 Specifications

  • ASTM A29 / A29M
  • ASTM A322 (Alloy Steel Bars)
  • ASTM A519 (Seamless Tubing)
  • SAE J404 Series Specifications
  • DIN EN 10083-3 (e.g., 34CrNiMo6)
  • ISO 683-1 / 683-2
  • JIS G4053 (SNCM Series)
  • AMS 6414 / AMS 6415 (Aerospace)
AISI 4340 Material Datasheet

AISI 4340 Properties

Chemical Composition
Elements C Mn P S Si Ni Cr Mo Fe
Min % 0.38 0.60 - - 0.15 1.65 0.70 0.20 Balance
Max % 0.43 0.80 0.035 0.040 0.30 2.00 0.90 0.30 Balance
Mechanical Properties
Annealed 745 470 22 % 217 HB
Normalized 1280 860 14 % 360 HB
Quenched & Tempered (400°C) 1520 1380 11 % 440 HB
Quenched & Tempered (550°C) 1170 1050 15 % 340 HB

AISI 4340 Characteristics

  • Ultra-high tensile strength combined with unparalleled structural toughness
  • Superior deep hardenability, maintaining strength across very large cross-sections
  • Exceptional resistance to shock, impact, and high-cycle torsional fatigue
  • Maintains excellent ductility and impact resistance even at sub-zero temperatures
  • Immune to temper embrittlement due to specific molybdenum stabilization

AISI 4340 Applications

  • Commercial aerospace structural components and landing gear assemblies
  • Heavy-duty oil & gas drill collars, downhole tools, and high-pressure valves
  • Locomotive and heavy machinery drive shafts, crankshafts, and massive gears
  • Ultra-high-stress industrial structural bolting and custom engineered studs
  • Wind turbine transmission components and heavy earth-moving equipment linkages