Once heat treated it becomes extremely hard and brittle. High carbon steel is very difficult to cut, bend and weld. Usually, carbon steel has a lusterless finish. Steel typically is considered to be carbon steel when the proportions of other trace elements in it do not exceed certain percentages. Carbon steel products, like pans and pots that are used for cooking, get hotter evenly than other steels. This article is the first of a four-part series on the different types of steel. This is true for pipeline systems that are used to gather or collect the natural gas, crude oil, or water; it is also true for those pipelines used to transport substances over distances from hundreds of feet to hundreds of miles. Carbon steel is a metal alloy that is formed as a result of combining iron and carbon. Carbon steel is composed of iron and 0.12 – 2.00 percent carbon. Mild steel is a form of carbon steel and it contains .05 – .29% carbon, while the medium type has .30 – .59%. The definition of carbon steel from the American Iron and Steel Institute (AISI) states: . Even within the confines of under two percentage points of carbon, there is huge variance in … no minimum content is specified or required for chromium, cobalt, molybdenum, nickel, niobium, titanium, tungsten, vanadium, zirconium, or any other element to be added to obtain a desired alloying effect; Carbon steel is a steel with carbon content from about 0.05% up to 2.1% by weight. The broader definition includes alloy steels, which can also contain up to 10.5 percent alloy content. Carbon steel is the almost exclusive choice of pipeline designers. Carbon Steel. High Carbon Steel: Commonly known as “carbon tool steel” it typically has a carbon range between 0.61% and 1.50%. The maximum percentages typically are 1.65 percent for manganese and 0.6 percent for copper and silicon.The copper percentage must be at least 0.4 percent.