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Sylvia Rose

Carbon Steel: Origins, Composition & Uses

Carbon steel is an essential material in various industries, renowned for versatility and strength. Uncover the secrets of carbon steel: how it’s made, components, properties, historical context, applications and its relationship with carbon (C) on a broader scale.



rolls of steel

How is Carbon Steel Made?


Carbon steel is a steel alloy primarily made of iron and carbon. The manufacturing process involves combining iron with carbon in varying proportions to achieve desired properties. Steelmakers carefully control carbon content to alter characteristics of the final product.


The production of carbon steel involves a process that typically includes the smelting of iron ore in a blast furnace. The key steps are as follows:


  1. Extraction: Iron ore is extracted from the earth's crust and is then crushed and concentrated.

  2. Smelting: The concentrated iron ore is combined with coke (a form of carbon) and limestone in a blast furnace. The heat generated from burning coke facilitates the reduction of iron ore into molten iron.

  3. Refining: The molten iron is poured into a converter where controlled amounts of carbon are added. This process helps in adjusting the carbon content to define the type of carbon steel being produced.

  4. Alloying: Additional elements, such as manganese, silicon, or nickel, can be introduced to enhance particular properties.

  5. Casting and Forming: Once the desired carbon and alloying elements are achieved, the steel is cooled and shaped through processes like rolling, forging, or casting.



creating a steel or iron spiral shape

What is Carbon?


Carbon is a non-metal element with the atomic number 6, essential for life on Earth. It is a fundamental component of organic materials and occurs in various forms, such as graphite and diamond.


In steel manufacturing, carbon serves as a crucial alloying element that imparts strength, hardness, and ductility to steel. When carbon atoms bond with iron, they enhance the strength and hardness of the resulting alloy, making it a fundamental component of steel production.



more carbon steel

When is Carbon Steel First Discovered?


The inception of carbon steel dates back centuries. Historically, carbon steel was first discovered during the Iron Age when ancient civilizations realized the benefits of combining carbon with iron to create stronger and more durable tools and weapons.


Carbon steel, in various forms, exists since ancient civilizations. Earliest evidence dates back to c. 1200 BCE, when artisans in Anatolia (modern-day Turkey) begin producing iron with varying amounts of carbon. The earliest steelworks, also in Anatolia, go back to c. 1800 BCE.



smelting metals

The specific term "carbon steel" becomes prevalent in the 19th century, during the industrial revolution, as understanding of steel composition and properties improved. Major industrial revolutions happen in countries like England and the newly-formed German Empire (1871 AD)


What are the Components of Carbon Steel?


Carbon steel consists of iron and carbon but may also contain small amounts of other elements like manganese, phosphorus, and sulfur. The proportion of carbon in the alloy significantly influences the steel's properties.



Carbon Structure

Knife and sword blade production typically uses carbon steel as it's flexible with a keen edge. Carbon steel primarily comprises:


  • Iron (Fe): The main element, typically constituting about 98-99% of the alloy.

  • Carbon (C): The key alloying element, present in varying amounts from 0.02% to over 2%.

  • Manganese (Mn): Often added to improve strength and hardenability.

  • Silicon (Si): Acts as a deoxidizer and increases strength.

  • Trace Elements: Small amounts of various elements like sulfur and phosphorus may be present as impurities.


Carbon black, including subtypes like acetylene black, channel black, furnace black, lamp black and thermal black, is a substance created by incomplete combustion of coal tar, organic materials or petroleum byproducts such as fuel oil or tar.



Worker at carbon black plant in Sunray, Texas (photo John Vachon, 1942)
Worker at carbon black plant in Sunray, Texas (photo John Vachon, 1942)

Carbon black is a colorant and strengthening agent in tires and various rubber goods; as a pigment and protective additive in plastics, paints, and ink. In the EU, it is permitted for use as a food coloring agent when derived from organic sources (E153).


Metallurgical Carbon Black is primarily utilized as an additive in steel manufacturing during continuous casting. It serves as a heat preservation agent, carbon blending agent, and drainage agent in the steel production process.


By increasing carbon content percentage, steel can be hardened and strengthened by heat treatment, but loses ductility. Weldability decreases with higher carbon content. regardless of heat treatment. In carbon steels, a higher carbon content results in a lower melting point.



carbon and ash
Charcoal in the works

Properties of Carbon Steel


Carbon steel boasts several desirable properties, including high tensile strength, durability, and excellent machinability. Its versatility makes it a popular choice across various industries, from construction to manufacturing.


Carbon steel exhibits a range of properties depending on its carbon content and other factors:


  • Strength: Higher carbon content typically increases strength.

  • Ductility: Low-carbon steels are more ductile, which makes them easier to form.

  • Hardness: As carbon content rises, hardness and wear resistance generally improve.

  • Weldability: Low-carbon steels are easier to weld compared to high-carbon varieties.



guy welding

Does Carbon Steel Rust?


Yes, carbon steel is susceptible to rust when exposed to moisture and oxygen. The iron in carbon steel can oxidize, leading to corrosion unless protected by coatings, painting, or galvanization.


Does Carbon Steel Turn Black?


Carbon steel can appear black due to oxidation or the formation of a black oxide layer, especially when it undergoes certain heat treatments or surface treatments. Some processes, like blackening, enhance appearance and offer limited corrosion resistance.


Over time, carbon steel develops a protective dark patina known as a black oxide layer. This natural process contributes to the material's aesthetics and offers additional protection against corrosion.



Graphite, a carbon product
Graphite, a primary carbon product

Uses of Carbon Steel


Carbon steel finds widespread applications in construction, automotive manufacturing, infrastructure development, and toolmaking. Its strength and versatility make it indispensable in numerous everyday products and structures.


Carbon steel is widely used across various sectors:

  • Construction: Used for structural beams, rebar, and steel frames.

  • Manufacturing: Commonly found in machinery parts, automotive components, and tools.

  • Consumer Goods: Often used in appliances, cutlery, and kitchenware.

  • Infrastructure: Pipes, railings, and bridges are often constructed from carbon steel due to its robustness.


How Much Carbon is in Your Body?


On average, a human body contains about 18% carbon, primarily in the form of organic compounds such as carbohydrates, amino acids, and lipids that are fundamental to life.

This essential element forms the building blocks of life. It's present in all organic substances.



how much carbon is in your body


Non-Fiction Books:


Fiction Books:

READ: Lora Ley Adventures - Germanic Mythology Fiction Series

READ: Reiker For Hire - Victorian Detective Murder Mysteries





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