High carbon steel has been around for a very long time. Although it is hard to pinpoint its exact origins, it is believed that one of the first carbon steels was "Wootz steel", which originated in South India around the 6th century BCE and was commonly traded to surrounding countries.
In the 3rd century Chinese metal smiths began producing the earliest known high-quality carbon steels. Later on in the 11th Century Damascus steel was produced in the Middle East, and in the 12th Century Sri Lanka was producing high-quality carbon steel for export. In the 1700s and 1800s European scientists developed an interest in mass producing cost-effective high-quality steel, and it wasn't until the mid to late 1800s when steel production became widespread.
In the early days of steel mass production it was mainly used to produce weaponry and infrastructure, but in the 1950 and 1960s further developments in steel production allowed for the use of steel in smaller consumer products. Some steels that were produced in the early 1900s such as 01 and A2 are still commonly used in the knife industry today.
Carbon steels are widely used in the knife industry today - especially in outdoor fixed blade knives - but many carbon steels have found their way into folding knives as well. Not only are the aforementioned older carbon steels used, but the industry has been hard at work creating new carbon steels that have been well-received by knife makers and knife users alike.
Here we'll be discussing some of the general pros and cons of high carbon steels, but also check out our previous article all about the many different types of steel that are out there.
While there are exceptions to each of these points, here are the general characteristics of most commonly used high carbon steels.
Toughness: High carbon steels are known for being incredibly tough, making them ideal for hard use tasks in the outdoors and in tactical settings. Very few stainless steels come close to the toughness of a majority of high carbon steels on the market. This high level of toughness decreases the likelihood of the blade breaking under hard use tasks such as chopping or batoning wood, as well as prying tasks.
Ease of sharpening: Aside from a few exceptions, most high carbon steels are relatively easy to sharpen using a simple whetstone or axe puck. This makes carbon steel a great choice for axes as well as knives that are used frequently in the field.
Cost: Most high carbon steels are less costly than stainless and super steels, making them not only a great choice for budget-conscious consumers but also for custom knife makers.
Ease of heat treating, shaping, and grinding: Many carbon steels are easier to heat treat, shape, and grind than stainless and super steels. This allows custom knife makers to produce all of their blades in-house without the need for advanced equipment or outside heat treating services.
Just like the pros, these are general characteristics. Though some exceptions do exist, you can expect these cons to apply to most high carbon steels.
Corrosion resistance: Due to the high carbon content and lower chromium content most of these steels lack corrosion resistance, making them much more susceptible to darkening and rust. This is particularly evident when working in wet environments or exposing the blade to acids that can be found in some foods.
Edge retention: Most carbon steel has a lower edge retention rating than high-end stainless steel. While this does add to the ease of sharpening, chances are you will have to maintain your edge more frequently with a carbon steel blade than most high-end stainless steels.
It is easy to see why carbon steels are a popular choice for hard-use knives. The toughness and ease of edge maintenance is a major advantage in the field, but the glaring issue of the lack of corrosion resistance can be a major turn-off for some people.
Fortunately, there are several things you can do to ensure you keep your high carbon steel blade running at peak performance despite the drawbacks. Here are some of the tools and techniques I use on a regular basis to keep my knives and axes functional for years to come.
Edge maintenance: I employ three simple and compact tools that remain in my pack to keep my knife and axe edges running at peak performance.
Corrosion protection: One can use a few different methods to help prevent harmful corrosion build-up. First, it is important to note the difference between patina and rust: patina is surface discoloration of the steel and is almost unavoidable when using high carbon steel, whereas rust is harmful corrosion that can cause pitting and damage the blade.
A big thank you to @barkhandle and Knives by Nuge for providing some excellent photos for this article!
Read Less
The difference in carbon content
The fundamental difference between high carbon steel and low carbon steel lies in their carbon content. Carbon is one of the key elements that influence the properties and characteristics of steel. In general, high carbon steel contains a higher percentage of carbon compared to low carbon steel.
Low carbon steel, also known as mild steel, typically contains a carbon content ranging from 0.05% to 0.25%. It is the most common form of steel due to its affordability and versatility. The low carbon content makes it relatively soft and ductile, which means it can be easily formed, machined, and welded. Low carbon steel also exhibits good toughness and is suitable for applications that require moderate strength and flexibility, such as construction materials, automotive components, and machinery parts.
On the other hand, high carbon steel contains a carbon content ranging from 0.6% to 1.0% or even higher. The increased carbon content results in a harder and stronger material with reduced ductility. High carbon steel is known for its excellent hardness and wear resistance, making it suitable for applications that require cutting tools, blades, springs, and high-strength wire. However, due to its reduced ductility, high carbon steel is more brittle and less able to withstand impacts and deformation without fracturing.
The carbon content in steel affects several important properties and characteristics:
1. Hardness: Increasing the carbon content enhances the hardness of steel. High carbon steel can achieve higher levels of hardness through heat treatment, such as quenching and tempering, making it suitable for applications where hardness is crucial.
2. Strength: The carbon content positively influences the strength of steel. High carbon steel exhibits greater strength compared to low carbon steel. This increased strength allows high carbon steel to withstand higher loads and stresses.
3. Ductility: Ductility refers to the ability of a material to deform without fracturing. Low carbon steel has higher ductility due to its lower carbon content, making it more suitable for forming and shaping processes. High carbon steel, on the other hand, is less ductile and more prone to fracture under stress.
4. Toughness: Toughness is a measure of a material’s ability to absorb energy before fracturing. Low carbon steel generally exhibits better toughness than high carbon steel. The increased brittleness of high carbon steel reduces its ability to absorb impact energy and makes it more susceptible to sudden failure.
5. Machinability: Low carbon steel is easier to machine and work with due to its improved ductility and lower hardness. High carbon steel, with its increased hardness, can be more challenging to machine, requiring appropriate tools and techniques to achieve desired results.
Environmental impact of high carbon steel and low carbon steel
The environmental impact of high carbon steel and low carbon steel varies significantly due to differences in their carbon content and the associated production processes. High carbon steel, with its elevated carbon content, typically requires more energy-intensive production methods, such as increased coal consumption during steelmaking. This leads to higher greenhouse gas emissions, including carbon dioxide (CO2) and other pollutants. Additionally, high carbon steel often relies on mining and extraction of iron ore, which can have adverse environmental effects, such as habitat destruction, deforestation, and soil erosion. On the other hand, low carbon steel, with its lower carbon content, generally has a reduced environmental impact. The production of low carbon steel typically involves less energy consumption and lower greenhouse gas emissions compared to high carbon steel. Moreover, low carbon steel can be manufactured using recycled materials, reducing the need for virgin raw materials and minimizing the environmental footprint associated with mining and extraction. Overall, the carbon content and production processes of high carbon steel and low carbon steel play a crucial role in determining their respective environmental impacts.
Properties and Applications of High Carbon Steel
High carbon steel possesses unique properties that make it highly suitable for specific applications. With its increased carbon content, high carbon steel exhibits exceptional strength, hardness, and wear resistance. These properties make it ideal for various demanding applications. High carbon steel is widely used in the manufacturing of cutting tools, including drill bits, saw blades, and machining tools, where hardness and durability are crucial for efficient cutting and shaping processes. It is also employed in the production of springs, such as those used in automotive suspension systems and industrial machinery, due to its excellent strength and resilience. Additionally, high carbon steel finds applications in automotive components, particularly in the manufacturing of gears, shafts, and crankshafts, where its high strength and wear resistance are essential for enduring the stresses and demands of engine operation.
Properties and Applications of Low Carbon Steel
Low carbon steel, also known as mild steel, possesses several properties that make it highly versatile and widely used in various applications. It exhibits excellent malleability, which means it can be easily formed, bent, and shaped without cracking or breaking. Its high ductility allows it to be drawn into wires or stretched into thin sheets without significant deformation. Low carbon steel also demonstrates good weldability, enabling it to be joined together using various welding techniques without compromising its structural integrity. These properties make low carbon steel suitable for an extensive range of applications. It is commonly utilized in the manufacturing of structural components, such as beams, columns, and supports, due to its strength and ease of fabrication. Additionally, low carbon steel finds applications in pipelines, where its weldability and corrosion resistance make it ideal for transporting liquids and gases. Moreover, it is a preferred material for automotive bodies, as it combines strength, formability, and cost-effectiveness, contributing to lightweight yet durable vehicle structures.