Sae 4340

ENGINEERING STEELS

HIGH TENSILE STEEL – AISI 4340
AISI 4340 Nickel – Chrome - Moly High Tensile Steel, generally supplied hardened and tempered to condition “U” in sections up to 100mm, with atensile strength of 930 – 1080 MPa and aiming for this strength range in larger sections. It offers a very good balance of strength, toughness and wear-resistance. Typical Applications: Heavy-dutyaxles, shafts, heavy-duty gears, spindles, pins, studs, collets, bolts, couplings, sprockets, pinions, torsion bars, connecting rods, crow bars, conveyor parts etc. Typical Chemical Analysis 0.40% Carbon0.25% Silicon 0.70% Manganese 1.85% Nickel 0.80% Chromium 0.25% Molybdenum Related specifications: AS 1444-1996 4340 BS EN10083-1-1991 817M40 BS 970-1955 EN 24 JIS G 4103 SNCM 439 SAE & UNS 4340 &G43400 Werkstoff 1.6565 40NiCrMo6

Surface Treatment: Will Nitride with a typical surface hardness up to HRC 60. Will Flame or Induction harden with a typical surface hardness up to HRC 58. MechanicalProperty Requirements in Condition “U” - to AS 1444-1996 Impact Section 0.2% Proof Tensile Elongation Izod Charpy Stress Strength On 5.65√So mm MPa MPa % J J *up to 63 755 min 930 – 1080 9 min 47 min42 min up to 100 740 min 930 – 1080 12 min *Applies only to bars bright drawn after hardening and tempering

Hardness HB 269 – 331 269 – 331

Typical Mechanical Properties – Hardened and temperedin section size listed. Section Yield Strength Tensile Strength Elongation Izod Hardness in mm MPa MPa % J HB 880 1000 17 85 295 50 850 980 17 80 290 100 730 930 17 75 275 200 Typical properties forguidance only

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High Tensile Steel – AISI 4340 Welding: Readily welded in the annealed condition but avoid when possible if hardened and tempered due to theeffect on the mechanical properties. Welding in the nitrided, flame or induction hardened condition is not recommended. Welding procedure: Low hydrogen electrodes are recommended. Pre-heat at 200°C –...