AISI 4140

Chromium, Molybdenum steel for applications requiring high tensile strength and toughness values, in particular in medium and large cross sections in the quenched and tempered condition. The Molybdenum additions prevent the steel from being susceptible to temper brittleness. Surface hardenable.

Available Product Shapes

  • Block
  • Ground
  • Round Bars
  • Square
  • Hollow Bar
  • Hex Bar
  • Flat Bar (incl. Square Bar)

Product Features

  • Hardenability: good
  • Machinability: good
  • Strength: good

Technical Data

C Si Mn Ni Cr Mo S P
0.40 0.20 0.80 - 1.00 0.20 0.02 0.02
Forge Normalize Anneal Stress Relieve Harden Temper Nitride
850-1050 °C. Cool in furnace. 840-880 °C. Air cool. 680-720 °C. Cool slowly in controlled furnace. In the quenched and tempered condition, about 30-50 °C below the tempering temperature. Air cool. In the annealed condition, 600-650 °C. Air cool. 830-860 °C Oil quench. 540-680 °C hold for 1 hour min. at temperature, air cool. (see tempering chart) Suitable for both liquid and gas nitriding.
AS DIN BS AISI
4140 1.7225 EN19A 4140