Introduction: Identify Metals
If your like me and make scrap metal sculpture then it can sometimes be hard to identify what metal the scrap is made of. In this instructable I will show you how too identify some of the more common metals. NOTE: These are not all the metals there are, there are thousands and I couldn't possibly tell about all of them. Also if you bend tin it will make a light "snapping" sound.
Step 1: Ferrous or Nonferrous?
Ferrous means that the metal has iron content which in most cases makes it magnetic and nonferrous means it doesn't have iron in it. An example of a ferrous metal is mild steel, also known as low carbon steel. An example of a nonferrous metal is copper or aluminum. Its always a good idea to bring a magnet to the scrap yard.
Step 2: Aluminum
Aluminum is a shiny grey metal and has a clear oxide that forms on contact with air. This may not be the best thing for identifying it, but aluminums melting point is 658° C (1217°F). Also aluminum is non sparking. Aluminums density is 2.70 g/cm3, this is a good way to identify it because you can find the density of a material by density = mass ÷ volume. As i said earlier, aluminum is nonferrous.
Step 3: Bronze
Most bronze is an alloy of copper and tin, but architectural bronze actually has a small amount of lead in it. Bronze has a dark coppery color and gets a green oxide over a period of time. bronze's melting point is 850-1000°C (1562-1832°F) depending on how much of each metal is in it. Bronze is nonferrous. Because bronze is an alloy densities vary. Bronze vibrates like a bell when hit.
Step 4: Brass
Brass is another copper alloy but it has zinc instead of tin. Brass has a yellow gold color. Brass' melting point is 900-940°C (1652-1724°F) depending on how much of each metal they used. Brass is nonferrous. Because brass is an alloy its density varies. If hit brass vibrates like a bell, this can be used to determine if something is brass instead of gold.
Step 5: Chromium
Chromium is a very shiny silver color and forms a clear oxide over time. Chromiums melting point is 1615°C (3034°F). Things are rarely made of pure chromium but lots of things are coated with it to make it shiny and not rust. Chromiums density is 7.2 g/cm3. Chromium is nonferrous.
Step 6: Copper
Copper is made into many alloys like brass and bronze. Copper is light red in color and gets a green oxide over time. Copper is nonferrous. Coppers melting point is 1083°C (1981°F). Coppers density is 8.94 g/cm3. Copper, like brass, also vibrates like a bell when hit.
Step 7: Gold
Gold is a shiny yellow color and does not have an oxide. Golds melting point is 1064.18°C (1947.52°F). Gold is very soft and is very heavy. Gold has a high electrical conductivity (more electricity can pass through it) which means that the connectors on many cords have gold plating. Golds density is 19.30 g/cm^3. Gold is nonferrous. Gold is a "precious" metal which means that it is very expensive and is used in coins and jewelry.
Step 8: Iron
Iron is ferrous (finally!) and magnetic. Iron is a dull grey when unpolished and its rust is a reddish color. Iron is also used in a lot of alloys like steel. Irons melting point is 1530°C (2786°F). Irons density is 7.87 g/cm3.
Step 9: Lead
Lead is a dull grey when unpolished but shinier when polished. Lead has a relatively low melting point, 327°C (621°F). Lead is nonferrous. Leads is very heavy, its density is 10.6 g/cm3.
Step 10: Magnesium
Magnesium has a grey color and develops an oxide that dulls the color. Magnesiums melting point is 650°C (1202°F). Magnesium is extremely flammable in a powder or thin strips. Magnesium burns very brightly and is very hard to put out because it is so hot that if you throw water on it, it separates it into hydrogen and oxygen, two very flammable gasses. Magnesium can also burn without oxygen making it even harder to put out. Magnesium is very light with a density of 1.738 g/cm^3. Because magnesium is so light it is used in engin blocks in cars, and because it burns so brightly it is used in incendiary weaponry (to incinerate things) and fireworks.
Step 11: Mild Steel
Mild steel is black to dark grey unpolished and silvery polished. Mild steel has the same red rust oxide as iron. Mild steel is also ferrous and magnetic. Another name for mild steel is low carbon steel. Mild steel makes yellow sparks when ground down. Mild steels density is about 7.86 g/cm3but it varies since it is an alloy of iron and carbon (low carbon steel). MIld steel melting point is 1350-1530°C (2462-2786°F).
Step 12: Nickel
Nickel is shiny silver when polished and is darker unpolished. NIckel is one of the few metals that is not an iron alloy that is magnetic (5¢ US nickels are not magnetic because there made of a copper nickel alloy). Nickels melting point is 1452°C (2645°F). Nickels density is 8.902 g/cm3.
Step 13: Stainless Steel
Stainless steel is a shiny silver color and does not forme and oxide. Chromium (step5) is mixed into the steel, when it hardens the chromium leaves a coating of its oxide on top of the steel, this is too thin to see so the steels color shows through. Stainless steels melting point is from 1400-1450 °C (2552-2642 °F). Stainless steels density varies because it is an alloy. Depending on the alloy some stainless steels are magnetic, but all are ferrous.
Step 14: Tin
Tin is silvery grey in color (like most metals) when polished and darker when unpolished. Tin has a comparatively low melting point of 231°C (449°F). Tins density is 7.365 g/cm3. Tin is nonferrous
Step 15: Titanium
Titanium is a silvery grey metal metal when unpolished and darker when unpolished. Titanium gives off bright white sparks when it is ground. Titanium is nonferrous. Titaniums melting point is 1795°C (3263°F). Titaniums density is 4.506 g/cm3.
Step 16: Silver
Silver is a shiny grey even before being polished but develops a black film over time and has to be polished. Silvers melting point is 961.78°C (1763.2°F). Silver has the highest electrical conductivity (more electricity can pass through it) than any other metal. Silvers density is 10.49 g/cm^3. Silver is nonferrous. Silver is a "precious" metal meaning that it is expensive and is used in coins and jewlery.
Step 17: Zinc
Zinc is naturally dull grey and is very hard to polish. Zinc has has an oxide that flakes off carrying some of the zinc so other things are coated in it so the zinc "rusts" instead of the base metal, this is called galvanization. Because of its low cost zinc is the main metal in us pennies. Zincs melting point is 419°C (786°F). Zinc is nonferrous. Zincs density is 7.14 g/cm3.