Tensile strength Facts for Kids

Tensile strength is a measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks.

The tensile strength of a material is the maximum amount of tensile stress that it can take before failure, for example breaking.

There are three typical definitions of tensile strength:

Yield strength - The stress a material can withstand without permanent deformation. This is not a sharply defined point. Yield strength is the stress which will cause a permanent deformation of 0.2% of the original dimension.

Breaking strength - The stress coordinate on the stress-strain curve at the point of rupture.

Typical tensile strengths

Some typical tensile strengths of some materials:

Typical tensile strengths of some materials
Material	Yield strength (MPa)	Ultimate strength (MPa)	Density (g/cm³)
Structural steel ASTM A36 steel	250	400	7.8
Steel, API 5L X65 (Fikret Mert Veral)	448	531	7.8
Steel, high strength alloy ASTM A514	690	760	7.8
Maraging_Steel, Grade 350	2400	2500	8.1
Steel Wire			7.8
Steel, Piano wire	c. 2000		7.8
High density polyethylene (HDPE)	26-33	37	0.95
Polypropylene	12-43	19.7-80	0.91
Stainless steel AISI 302 - Cold-rolled	520	860	8.03;
Cast iron 4.5% C, ASTM A-48	130 (??)	200	7.3;
Titanium Alloy (6% Al, 4% V)	830	900	4.51
Aluminum Alloy 2014-T6	400	455	2.7
Copper 99.9% Cu	70	220	8.92
Cupronickel 10% Ni, 1.6% Fe, 1% Mn, balance Cu	130	350	8.94
Brass		250
Tungsten		1510	19.25
Glass (St Gobain "R")	4400 (3600 in composite)		2.53
Bamboo	142	265	.4
Marble	N/A	15
Concrete	N/A	3
Carbon Fiber	N/A	5650	1.75
Spider silk	1150 (??)	1200
Silkworm silk	500
Kevlar	3620		1.44
Vectran		2850-3340
Pine Wood (parallel to grain)		40
Bone (limb)		130
Nylon, type 6/6	45	75	1.15
Rubber	-	15
Boron	N/A	3100	2.46
Silicon, monocrystalline (m-Si)	N/A	7000	2.33
Sapphire (Al₂O₃)	N/A	1900	3.9-4.1
Carbon nanotube (see note below)	N/A	62000	1.34

Note: Multiwalled carbon nanotubes have the highest tensile strength of any material yet measured, with labs producing them at a tensile strength of 63 GPa, still well below their theoretical limit of 300 GPa. However, as of 2004, no macroscopic object constructed of carbon nanotubes has had a tensile strength remotely approaching this figure, or substantially exceeding that of high-strength materials like Kevlar.

Note: many of the values depend on manufacturing process and purity/composition.

Elements in the annealed state	Young's Modulus (GPa)	Proof or yield stress (MPa)	Ultimate strength (MPa)
Aluminium	70	15-20	40-50
Copper	130	33	210
Gold	79		100
Iron	211	80-100	350
Lead	16		12
Nickel	170	14-35	140-195
Silicon	107	5000-9000
Silver	83		170
Tantalum	186	180	200
Tin	47	9-14	15-200
Titanium	120	100-225	240-370
Tungsten	411	550	550-620
Zinc (wrought)	105		110-200

(Source: A.M. Howatson, P.G. Lund and J.D. Todd, "Engineering Tables and Data" p41)

Two vises apply tension to a specimen by pulling at it, stretching the specimen until it fractures. The maximum stress it withstands before fracturing is its ultimate tensile strength.