What distinguishes high carbon steel from low carbon steel?

High carbon steel is distinguished from low carbon steel primarily by its greater hardness. This characteristic is attributed to its higher carbon content, which ranges from approximately 0.6% to 1.4%, compared to low carbon steel, which typically contains less than 0.3% carbon. The increased carbon content enhances the steel's ability to harden through heat treatment processes such as quenching. As a result, high carbon steel is often used in applications that require materials to be very hard and wear-resistant, such as cutting tools and blades. This hardness makes it suitable for manufacturing products that need to withstand high levels of stress and abrasion.

The other characteristics, such as cost, rust-resistance, and malleability, are not accurate distinctions between high and low carbon steel in this context. High carbon steel is generally more expensive due to its increased carbon content and the processes involved in producing it, while its rust resistance does not notably differ from that of low carbon steel. Additionally, high carbon steel tends to be less malleable compared to low carbon steel, making it more brittle and reducing its ability to deform under stress. Thus, the superior hardness of high carbon steel distinctly sets it apart from its low carbon counterpart.