Making steel is just like baking- each type has its own recipe and variations to get what you’re looking for. Sticking to the recipe is key in baking. If you add too much flour, your cake will be dry. If you add an extra egg, it’ll be richer. Think of steel in that way, except your ingredients are elements such as carbon, iron, manganese, and so on. Below is a list of 11 properties that can be found in steel and what they contribute to the recipe.
- Iron – Smelted from iron ore, iron is the main ingredient in steel. Think of it as the flour, or for the gluten-free folks, the coconut flour.
- Carbon – Carbon is the main hardening agent in steel. The more carbon, the harder the steel. It also gives it more brittleness, so you have to walk the line in the amount of carbon added to complement the properties needed. Higher levels also require special welding procedures to produce a good weld.
- Manganese – Also increases the hardness of steel. It helps stabilize austenite structure at lower temperatures also.
- Chromium – This aids in hardening through heat treatment. It increases corrosion resistance and resistance to oxidation and high temperatures.
- Nickel – Another element to increase hardenability, it also helps with corrosion resistance, strength, and toughness.
- Molybdenum – Molybdenum will improve corrosion resistance, strength, and hardness of the steel.
- Titanium – Reduces corrosion and grain structure in steel.
- Copper – Can be used for corrosion resistance, but makes it hard to weld if there are high levels.
- *Boron – Added in very small amounts, this element enhances heat treat response, meaning it helps improve strength and toughness. It can be used as a substitute for higher prices alloys.
- *Phosphorous – Usually considered detrimental as it creates voids in steel, phosphorous increases strength and hardness, to a degree, at the expense of ductility. Although good for machining, it’s generally considered undesirable.
- Sulfur – Sulfur is like getting eggshell in the mix, it’s an impurity. Unlike an eggshell, you can’t quite get it all out. It creates voids or minute inclusions in the steel, allowing for chips to break when machining. Fewer chips will adhere to the tooling too, improving machinability. Ductility and toughness will be lowered.
| Element | Primary Role | Effects & Characteristics |
| Iron (Fe) | Base | Main ingredient |
| Carbon (C)* | Hardener | Increases hardness and strength, also increases brittleness |
| Manganese (Mn) | Hardener | Increases hardness and helps stabilize austenite structure at low temperatures |
| Chromium (Cr) | Protector | Improves corrosion resistance and aids hardening through heat treatment |
| Nickel (Ni) | Strengthener | Increases toughness, strength, and corrosion resistance |
| Molybdenum (Mo) | Reinforcer | Improves corrosion resistance, strength, overall hardness |
| Titanium (Ti) | Refiner | Reduces corrosion and grain structure of the steel |
| Copper (Cu) | Protector | Boosts corrosion resistance, but high levels make welding difficult |
| Boron (B) | Enhancer | Added in small amounts to improve strength and heat treat response |
| Phosphorus (P) * | Impurity | Increases strength, but makes steel brittle |
| Sulfur (S) * | Impurity | Decreases toughness, but improves machinability |
*More info in list
These are not the only elements that go into steel either, but these are some of the most common ones. Just like in baking, knowing how your elements affect the end product is important so you can make modifications to get the desired result. Now that you know what goes into steel, take a look at our post on How Steel Is Made to learn about the process of creating steel.