Carbon steel: High and low carbon steel content, grades, properties

There are different types of steel used for industrial purposes. One of the most common types of steel is carbon steel, mainly used in the construction industry for building marine structures, powerplants etc., and the automotive industry for building automobile parts.

What is carbon steel?

As the name suggests, carbon steel is an alloy of carbon and iron. During the steel manufacturing process, carbon is mixed with molten iron to form steel. The carbon percentage in steel added during the manufacturing process determines whether it is carbon steel or other forms of steel.

Carbon steel is steel containing carbon ranging from 0.12% to 2%. Steel is considered to be carbon steel when there is no mention of a particular amount additive elements including molybdenum, nickel, chromium, tungsten, zirconium, titanium, cobalt, vanadium, etc., is specified.

Types of carbon steel

Depending on the content of carbon added there are different types of carbon steel:

Low-carbon steel

Containing up to 0.30% carbon, this is the largest category of steel that is features in flat-rolled products like steel sheets or strips. Products made of low-carbon steel are usually in cold-rolled and annealed condition. The carbon percentage in carbon steel is very low featuring less than 0.10% carbon with up to 0.4% manganese. Sometimes for rolled steel structural plates and sections, the carbon content is increased to 0.30%, with higher manganese content up to 1.5%. These plates and sections are used for forgings, boiler plates, seamless tubes, and stampings.

Uses and applications

• Automobile body panels
• Tin plates
• Steel wire products

Properties of low carbon steel

• Low hardness
• High ductility
• Toughness
• Machinability
• Weldability

Medium-carbon steel

The percentage of carbon in medium-carbon steel ranges from 0.30 to 0.60%. The manganese content is typically from 0.60 to 1.65%. Increasing the carbon content to approximately 0.50% along with the manganese content allows medium carbon steels to be used in the quenched and tempered condition.

Uses and applications

The uses of medium-carbon steels include shafts, crankshafts, axles, couplings, gears and forgings. Steel with 0.40% to 0.60% carbon range is also used to manufacture rails, railway wheels and rail axles.

Properties of medium carbon steel

• Low hardenability
• Medium strength
• Ductile
• Tough

High carbon steel

High-carbon steels feature 0.60 to 1.00% carbon content with manganese content ranging from 0.30% to 0.90%. This kind of steel is used for making spring materials and high strength steel wires.

There is also a category called ultra-high-carbon steel which is an experimental steel alloy containing 1.25% to 2.0% carbon content. These steels are thermomechanically processed to produce microstructures that consist of ultrafine grains of spherical, discontinuous proeutectoid carbide particles.

Uses and applications

The application of high carbon steel includes cutting tools, high-strength wire, punches, springs, drill bits knives, etc., while ultra-high carbon steel is used for manufacturing hard materials like large machine parts, hot water radiators, metal lamp posts, blades, cutting tools, etc.

Properties of high carbon steel

• Low hardenability
• Medium strength
• Ductility
• Toughness

Also read: MS flat: Check different sizes, uses, how to buy

Grades of carbon steel

According to a user guide published by SAIL (Steel Authority of India Limited), given below are the carbon steel grades:

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Author: Priyanka Babu

Priyanka is a seasoned content marketing professional with more than 6 years of experience crafting various forms of business and technology sector content. Her insightful writing tackles critical issues faced by small-scale manufacturing businesses. Priyanka’s clear and concise communication empowers businesses to make informed decisions and thrive in today’s dynamic business environment.