Material Properties AISI 4340 Steel Annealed admin May 20, 2016 Material Properties for AISI 4340 Steel Annealed Physical specifications of materials. Materials AISI 4340 Steel Description Annealed Density g/cc 7.85 lb/in^3 0.284 Hardness Brinell unless specified 217 Tensile Strength ultimate Mpa 745 Ksi 108.025 Yield Strength MPa 470 Ksi 68.15 Modulus of Elasticity Gpa 205 10^6 Psi 29.71014488 Poisson’s Ratio 0.29 %Elongation at break 22 %Reduction of area 50 Izod Impact J 51 Ft-lb 37.6278 Fracture Toughness Mpa(m)^0.5 Ksi(in)^0.5 Thermal conductivity W/m-K 44.5 Btu/ft-h-F 25.722543349 Specific Heat Cpacity J/g-K 0.475 Btu/lb-F 0.114 Coefficient of thermal expansion 1E-6/K 12.3 1E-6/F 6.8436090171 Electrical Resistivity Ohm-cm 0.0000248