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Bulk Modulus for Materials Metals and Liquids

Engineering Materials

Bulk Modulus for Materials Metals and Liquids

A liquid‘s compressibility is measured in terms of its bulk modulus of elasticity. Compressibility is the percentage change in unit volume per unit change in pressure:

The mass flow rate can be determined, since it is related to the differential pressure within the uncertainty limits stated in ISO 5167, using Equation (1):

Eq. 1
C = δv / v / δp

The bulk modulus of elasticity K is its reciprocal:

Eq. 2
K = 1/C

or

K = v · δp / δv

Where:

K = pressure
C = Coefficient of discharge
v = original volume
δv = change in volume
δp = change in pressure

Bulk Modulus for Selected Solid (Metals)

Material Bulk Modulus	Units (106 psi)	Units (1010 Pa)
Aluminum, var. alloys	9.9 - 10.2	6.8258 - 7.033
Boron Carbide (B4)	29.0	20 - 24
Brass, 70–30	15.7	1.0825
Brass, cast	16.8	11.583
Carbon (Diamond)	79.77	55 - 64
Cast steel	20.2	13.927
Concrete	0.8702 - 4.06	0.6 - 2.8
Copper	17.9	12.342
Elektron (magnesium alloy)	4.8	3.3095
Iron, cast	8.4 -15.5	5.7916 -
Iron, malleable	17.2	10.687
Magnesium alloy	4.8	3.3095
Monel metal	22.5	15.513
Phosphor bronze	16.3	11.238
Silver	13.924 - 15.374	9.6 - 10.6
Solder (Tin-Lead)	4.786 - 8.4122	3.3 - 5.8
Stainless steel 18–8	23.6	16.272
Steel, cast	20.2	13.927
Steel, cold-rolled	23.1	15.927
Steel, all others	22.6 - 24.0	15.582 - 16.547
Tin	6.09 - 8.4	4.2 - 6.0
Tobin bronze	16.3	11.238
Tungsten	44.53 - 15.542	30.7 - 31.4

Data represent typical values, but material properties may vary widely, depending on exact composition, material condition, and processing.

Bulk Modulus for Liquids

English Units
( 10 5 PSI) SI Units
( 10 9 Pa)

Bulk Modulus for Liquids	Units (105 psi)	Units (109 Pa)
Acetone	1.34	0.92
Benzene	1.5	1.05
Carbon Tetrachloride	1.91	1.32
Ethyl Alcohol	1.54	1.06
Gasoline	1.9	1.3
Glycerin	6.31	4.35
ISO 32 Mineral Oil	2.6	1.8
Kerosene	1.9	1.3
Mercury	41.4	28.5
Paraffin Oil	2.41	1.66
Petrol	1.55 - 2.16	1.07 - 1.49
Phosphate Ester	4.4	3
SAE 30 Oil	2.2	1.5
Seawater	3.39	2.34
Sulfuric Acid	4.3	3.0
Water	3.12	2.15
Water - Glycol	5	3.4
Water - Oil Emulsion	3.3	2.3

Bulk modulus elasticity may also be expressed in terms of pressure and density:

K = (p₁ - p₀ ) / [(ρ₁ - ρ₀ ) / ρ₀ ]

Here, ρ₀ and (ρ₁ are the initial and final density values.

Related:

• Section Properties Area Moment of Inertia of Common Shapes
• Section Modulus Equations and Calculators Common Shapes
• Modulus of Elasticity, Youngs Modulus, Average Properties of Structural Materials, Shear Modulus, Poisson's Ratio, Density
• Spring Materials Modulus of Elasticity used in Torsion and Tension
• Young's Modulus (Elastic Modulus) Equation

Reference:

Rules of Thumb for Mechanical Engineers