Reference Page - Advanced NDT Limited

Advanced NDT Limited - Suppliers Of Non Destructive Testing Equipment.

Reference Material

Acoustical Properties Of Common Materials
Material	Ultrasonic Velocity
Material	Longitudinal		Transverse (Shear)		Impedance
	in / us	mm / us	in / us	mm / us	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

Ultrasonic Velocity Chart

Some useful reference material to view online or download for future use.

dB	Amplitude Ratio
0	1.0
0.5	1.06
1	1.12
2	1.26
3	1.41
4	1.59
5	1.78
6	2.00
7	2.24
8	2.51
9	2.82
10	3.16
11	3.55
12	3.98
13	4.47
14	5.01
15	5.62
16	6.31
17	7.08
18	7.94
19	8.91
20	10.00
40	100.00
60	1000.00
80	10000.00

Practical Focal Length Chart

The maximum focal length shown is approximately three-quarters of the distance to the end of the near-field. This theoretical boundary is called Y+, and is based on the sound pressure produced from a theoretical, single-frequency, transducer. Even the most narrowbanded transducers manufactured by NDT Systems radiate soundfields having a range of frequencies. The lower frequency components tend to reduce the effective Y+ distance; hence, the 0.75 Y+ maximum. This effect is even more pronounced with broadband transducers such as NDT Systems' High Resolution (HR) Series.

The practical maximum focal length of highly damped transducers tends to be closer to 0.6 Y+. The minimum practical focal lengths listed in the table below can be used to specify transducers useful only for very near-surface applications. Their depth of field is so limited that the soundfield diverges very rapidly beyond the focal point. As a rule of thumb, focal lengths midway between minimum and maximum produce an effective compromise between sensitivity and depth of field.

MHz	Element		Beam Dia	Focus Range		Approximate Beam Diameter @ Percentage of Yo+ Shown (in)
	Dia - In	Yo+	(-6dB@Yo)	Min	Max
						25%	50%	75%
0.5	0.5	0.53	0.126	N/P	N/P	N/P	N/P	N/P
	0.75	1.2	0.191	N/P	1.00	N/P	0.095	0.143
	1.00	2.14	0.255	1.00	1.50	0.064	0.128	0.191
	1.125	2.74	0.290	1.50	2.00	0.073	0.145	0.218
1.0	0.125	0.06	0.029	N/P	N/P	N/P	N/P	N/P
	0.25	0.27	0.064	N/P	N/P	N/P	N/P	N/P
	0.375	0.6	0.095	N/P	0.50	0.024	0.048	0.072
	0.5	1.07	0.128	N/P	0.75	N/P	N/P	0.096
	0.75	2.41	0.192	1.00	1.75	0.048	0.096	0.144
	1.00	4.28	0.255	1.50	3.00	0.064	0.128	0.191
	1.125	5.41	0.287	1.50	4.00	0.072	0.143	0.215
2.25	0.125	0.15	0.032	N/P	N/P	N/P	N/P	N/P
	0.25	0.6	0.064	N/P	0.50	N/P	N/P	0.048
	0.375	1.35	0.095	N/P	1.00	N/P	N/P	0.072
	0.5	2.4	0.127	1.00	1.75	0.032	0.064	0.095
	0.75	5.41	0.191	1.50	4.00	0.048	0.096	0.143
	1.00	9.63	0.255	2.00	7.00	0.064	0.128	0.191
	1.125	12.19	0.287	2.00	9.00	0.072	0.144	0.215
3.5	0.125	0.23	0.031	N/P	N/P	N/P	N/P	N/P
	0.25	0.94	0.064	N/P	0.75	N/P	N/P	0.048
	0.375	2.11	0.096	0.75	1.50	0.024	0.048	0.072
	0.5	3.75	0.128	1.00	3.00	0.032	0.064	0.096
	0.75	8.43	0.191	1.50	6.00	0.048	0.096	0.144
	1.00	14.98	0.255	2.00	11.00	0.064	0.128	0.191
	1.125	18.96	0.287	4.00	14.00	0.072	0.144	0.215
5.0	0.125	0.33	0.031	N/P	N/P	N/P	N/P	N/P
	0.25	1.34	0.064	0.50	1.00	0.016	0.032	0.048
	0.375	3.01	0.096	0.75	2.00	0.024	0.048	0.072
	0.50	5.35	0.128	1.00	4.00	0.032	0.064	0.096
	0.75	12.04	0.191	1.50	9.00	0.048	0.096	0.144
	1.00	21.4	0.255	4.00	16.00	0.064	0.128	0.191
7.5	0.125	0.5	0.032	N/P	N/P	N/P	N/P	N/P
	0.25	2.01	0.064	0.50	1.50	0.016	0.032	0.048
	0.375	4.51	0.096	0.75	3.50	0.024	0.048	0.072
	0.50	8.03	0.128	1.50	6.00	0.032	0.064	0.096
	0.75	18.06	0.191	3.50	13.00	0.048	0.096	0.144
10	0.125	0.67	0.032	N/P	0.50	N/P	N/P	N/P
	0.25	2.68	0.064	0.50	2.00	0.016	0.032	0.048
	0.375	6.02	0.096	0.75	4.50	0.024	0.048	0.072
	0.50	10.70	0.128	1.00	8.00	0.032	0.064	0.096
	0.75	24.08	0.191	1.50	10.00	0.048	0.096	0.144
15	0.125	1.00	0.032	0.50	0.75	0.008	0.016	0.024
	0.25	4.01	0.064	0.50	3.00	0.016	0.032	0.048
	0.375	9.02	0.096	0.75	7.00	0.024	0.048	0.072
	0.50	16.05	0.128	1.00	12.00	0.032	0.064	0.096
20	0.125	1.34	0.032	0.50	1.00	0.008	0.016	0.024
	0.25	5.35	0.064	0.75	4.00	0.016	0.032	0.048
	0.375	12.03	0.096	1.00	9.00	0.024	0.048	0.072
25	0.125	1.67	0.032	0.50	1.25	0.008	0.016	0.024
25	0.25	6.99	0.067	0.50	5.00	0.017	0.033	0.050

dB Ratio Chart

Yo+ Focal Chart

ADVANCED NDT LIMITED,
Orchard House, Orchard Close, Severn Stoke, Worcester, UK    WR8 9JJ
Telephone: 44 (0) 1905 371460        *** Fax:   44 (0) 1905 371477
E-Mail: sales@advanced-ndt.co.uk *** Website:   www.advanced-ndt.co.uk

Products and Specifications Subject to Change Without Notice. E & O.E.