kids encyclopedia robot

Tensile strength facts for kids

Kids Encyclopedia Facts

Tensile strength is a way to measure how much force it takes to pull something until it breaks. Imagine pulling on a rope, a wire, or even a strong metal beam. Tensile strength tells you the maximum pull it can handle before it snaps.

It's like testing how strong a material is when you stretch it. The higher the tensile strength, the more force it can resist before breaking.

There are three main ways to talk about tensile strength:

  • Yield strength: This is the amount of pull a material can handle without changing its shape permanently. Think of a rubber band: if you stretch it a little, it goes back to its original shape. But if you stretch it too much, it stays stretched out. The yield strength is the point just before it stays stretched.
  • Ultimate strength: This is the absolute maximum pull a material can take. It's the highest point of force it can stand before it starts to break or tear apart.
  • Breaking strength: This is the exact amount of pull on the material at the moment it finally breaks into pieces.

How Strong Are Different Materials?

Different materials have different tensile strengths. This means some things are much harder to break by pulling than others. Here's a table showing how strong some common materials are:

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: Some types of carbon nanotubes are the strongest materials ever measured. Labs have made them with a tensile strength of 63 GPa. This is still much lower than what scientists think they could be (300 GPa). However, as of 2004, no large object made of carbon nanotubes has been as strong as materials like Kevlar.
  • Note: The strength values can change a lot. It depends on how the material is made. It also depends on how pure it is or what it's mixed with.

Related pages

Images for kids

See also

Kids robot.svg In Spanish: Tensión de rotura para niños

kids search engine
Tensile strength Facts for Kids. Kiddle Encyclopedia.