Tensile strength
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.
- Ultimate strength - The maximum stress a material can withstand.
- 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:
| 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)
Tensile Strength Media
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.
Figure 1: "Engineering" stress–strain (σ–ε) curve typical of aluminum Template:Olist*
Round bar specimen after tensile stress testing
