Material Sound Velocities

The table below lists typical longitudinal wave ultrasonic velocities in a variety of common materials that can be measured with ultrasonic test equipment gages. Note that this is only a general guide. The actual velocity in these materials may vary significantly due to a variety of causes such as specific composition or microstructure, grain or fiber orientation, porosity, and temperature. This is especially true in the case of cast metals, fiberglass, plastics, and composites. For best accuracy in thickness gaging, the sound velocity in a given test material should always be measured by performing a velocity calibration on a sample of known thicknesses.


Acoustical Properties of Common Materials
Material Ultrasonic Velocity
Longitudinal Transverse (Shear) Impedance
(in./µsec) (mm/µsec) (in./µsec) (mm/µsec) Z
Metals
Aluminum 1100-0 0.248 6.229 0.121 3.073 17.1
Aluminum 2024-T4 0.251 6.375 0.124 3.150 17.6
Aluminum 6061-T6 0.248 6.299 0.124 3.150 17.0
Beryllium 0.507 12.878 0.350 8.890 23.5
Brass (70% Cu - 30% Zn) 0.172 4.369 0.083 2.108 37.1
Bronze (Phosphor 5%) 0.139 3.531 0.088 2.235 31.3
Copper (CP) 0.187 4.750 0.092 2.337 42.5
Gold 0.128 3.251 0.047 1.194 62.6
Hastelloy C 0.230 5.842 0.114 2.896 52.2
Hastelloy X 0.228 5.791 0.108 2.743 47.7
Inconel (Wrought) 0.308 7.823 0.119 3.023 64.5
Iron (Cast), Various Alloys 0.138-0.220 3.505-5.588 0.087-0.126 2.210-3.200 24.3-41.2
Lead (94Pb-6Sb) 0.085 2.159 0.032 0.813 23.5
Magnesium, Various Alloys 0.215-0.228 5.461-5.791 0.119-0.122 3.023-3.099 9.24-10.6
Monel 0.211 5.359 0.107 2.718 47.2
Nickel (CP) 0.222 5.639 0.117 2.972 50.0
Silver (0.99 Fine) 0.142 3.607 0.063 1.600 37.8
Steel 1020 0.232 5.893 0.128 3.251 45.4
Steel 4340 0.230 5.842 0.128 3.251 45.6
Steel , CRES 300 Series 0.221-0.226 5.613-5.740 0.120-.0123 3.048-3.124 44.6-45.4
Steel , CRES 400 Series 0.212-0.237 5.385-6.020 0.118-0.132 2.997-3.353 41.3-46.3
Titanium, 6AI-4V 0.243 6.172 0.130 3.302 27.3
Zircaloy 0.186 4.724 0.093 2.362 44.2
Zirconium 0.183 4.648 0.089 2.261 30.1
Polymers
Acrylics 0.105-0.109 2.667-2.769 0.044-0.057 1.118-1.448 3.15-3.51
Cellulose Acetate 0.096 2.438 No Shear Component 3.19
Nylon 0.016 2.692 No Shear Component -------------
Phenolic 0.056 1.422 No Shear Component 1.90
Polycarbonate 0.090 2.286 No Shear Component 2.71
Polyethylene 0.105 2.667 No Shear Component 2.94
Polystyrene 0.094 2.388 0.045 1.143 2.52
Rubber (Natural) 0.061 1.549 No Shear Component 1.74
Rubber (Carbon Filter) 0.066 1.676 No Shear Component -------------
Rubber (Silicone) 0.037 0.94 No Shear Component 1.40
Teflon 0.054 1.372 0.250 6.35 3.00
Miscellaneous Solids
Alumina (Al2O3) 0.427 10.846 No Shear Component 43.1
Concrete 0.167-0.207 4.242-5.258 0.135 3.429 12.4
Glass (Plate) 0.227 5.766 No Shear Component 14.5
Granite 0.156 3.962 0.076 1.93 10.9
Ice ( -16C) 0.150 3.81 No Shear Component 3.60
Quartz, Natural 0.226 5.74 0.139 3.531 15.2
Quartz, Fused 0.219 5.563 0.302 7.671 14.5
Sapphire 0.469 11.913 0.157 3.988 47.2
Tungsten Carbide 0.262 6.655 No Shear Component 67.6
Composite Materials
Fiberglass (50 v/o) 0.124 3.15 0.068 1.727 6.04
Graphite/Epoxy (60 v/o) 0.117 2.972 0.077 1.956 4.65
Boron/Epoxy (50v/o) 0.131 3.327 0.072 1.829 6.38
Liquids
Ethylene Glycol 0.064 1.626 No Shear Component 1.80
Glycerin 0.076 1.93 No Shear Component 2.42
Oil (SAE 20) 0.069 1.753 No Shear Component 1.51
Water (20C) 0.058 1.473 No Shear Component 1.48
Gases
Air (20ºC) 0.014 0.356 No Shear Component 0.00041
Nitrogen (20ºC) 0.014 0.356 No Shear Component 0.00041
Oxygen (20ºC) 0.013 0.33 No Shear Component 0.00043