Steel

Steel is an alloy of iron and carbon, and sometimes other elements. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, and weapons.

Description of what it is like

Steel is a hard, strong, greyish metal. It can be polished to a high shine. Unlike pure iron, it is much harder and holds a sharp edge better, making it ideal for cutting tools.

Origin and where to find it

• Not found in nature: Steel is a man-made alloy.
• Requires processing: It is created by refining iron and adding a specific amount of carbon (usually between 0.002% and 2.1%).

Minimum processing required

1. Smelting: Iron ore is smelted into pig iron.
2. Refining: Impurities are removed, and carbon content is adjusted (Bessemmer process or modern basic oxygen steelmaking).
3. Heat Treatment: Quenching and tempering to adjust hardness and toughness.

Tools needed to work on it

• Forge/Furnace: High temperatures are needed to work steel.
• Anvil and Hammer: For shaping.
• Grindstone: For sharpening and polishing.

Common forms of use

• Forged: Shaped while hot.
• Cast: Poured into molds (less common for tools).
• Machined: Cut and shaped with other harder tools.
• High Speed Steel (HSS): A specific alloy with tungsten and chromium that retains hardness at high temperatures, used for Drill Bits and Lathe Tools.

Possible substitutes

• Iron: Softer, loses edge quickly.
• Bronze: Easier to cast, resistant to corrosion, but softer than good steel.
• Titanium: Modern, lighter, stronger, but much harder to process.

Limitations and common failures

• Rust: Unless stainless (alloyed with chromium), steel rusts easily in damp environments.
• Brittleness: High carbon steel can be brittle if not tempered correctly.

Risks and safety

• High Heat: Working with molten or hot steel poses burn risks.
• Sharp Edges: Finished steel tools are very sharp.

Related materials

• Iron: Base metal for steelmaking.
• Reinforced Concrete: Steel is used as reinforcement (Rebar) in concrete.
• Coal: Carbon source for smelting and refining.
• Bronze: Alternative tool alloy with different properties.

Related Knowledge

• Forging