Material Basics - Iron & Steel

Iron is ...

• a chemical element from the periodic table (Fe)

• a man made material

• only found on earth in the form of an ore

• found in its pure form in the earths crust

An ore is ...

• the name of steel after it is heat treated

• mixture of elements created by the extreme heat and pressure of a meteor

• a man made combination of materials with specific properties

• a natural mixture of reactive elements found in the earths crust

Pure iron is ...

• softer than aluminum

• an extremely hard material which makes it difficult to work with

• found abundantly in the earths crust

• not found in nature as it is highly reactive

Steel is ...

• a man made mixture of iron with small amounts of other elements added called an alloy

• a natural ore including iron and other elements found in the earths crust

• a modern material developed after the industrial revolution

• an alloy which can be found in the earths crust

The most common element added to iron to create steel alloy is ...

• tungsten

• vanadium

• chromium

• carbon

Steel is an amazingly versatile material because we can make into a variety of alloys. Today there are over

• 500 types of steel

• 1500 types of steel

• 2500 types of steel

• 5000 types of steel

This type of steel was discovered by accident when an experiment went wrong, and includes over 11% of chromium

• stainless steel

• high strength steel (HSS)

• structural steel

• sheet steel (used for thin parts)

Varying the amounts of additives added to iron changes the properties of the steel alloy created. The material properties which can be effected are ...

• hardness

• ductility

• tensile strength

• opacity

The properties of steel can also be slightly modified using heat treatments. A heat treatment ...

• is heating the iron before it is alloyed

• is heating the additives before adding them into the pure iron

• is subjecting the alloying chamber to a specific time/temperature setting

• changes the crystal structure of the steel thereby effecting its properties

• is subjecting the finished alloy to specific time/temperature setting

Annealing is ...

• heating the steel alloy to a sufficiently high temperature to soften it, and remove built in stresses

• heating the steel alloy to a high temperature and rapidly cooling it, which hardens it but also makes it brittle

• moderately heating the finished steel alloy to remove some of the internal stresses and make it softer and less brittle

• storing the steel alloy at room temperature for a long period of time to cure it