1.2. Carbon Steels

Carbon steels are by far the most frequently used steel. In 1988 the United States produced 99.9 million tons of steel, including 86.8 million tons, or 86.9% of carbon steel (Ref 7, p.147). The feasibility of using carbon steels depends on whether or not their properties (tensile, yield, and fatigue strengths; impact resistance, need for heat treating, etc.) are suitable for the parts to be used. If the required characteristics can be obtained with carbon steel, most users select this less costly steel.

The American Iron and Steel Institute (AISI) defines carbon steel as follows: Steel is considered to be carbon steel when no minimum content is specified or required for chromium, cobalt, molybdenum, nickel, niobium, titanium, tungsten, vanadium or zirconium, or any other element to be added to obtain a desired alloying effect; when the specified minimum for copper does not exceed 0.40 percent; or when the maximum content specified for any of the following elements does not exceed the percentages noted: manganese 1.65, silicon 0.60, copper 0.60 (Ref 7, p.147) .

Sometimes the term plain carbon steel is used instead of carbon steel. It is acceptable, but no longer considered best practice. Some of the cutting tool companies such as KOMET of America (Ref 10), Sandvik Coromant (Ref 11), and WALTER Waukesha (Ref 12) define carbon steel as unalloyed steel; Greenleaf Corporation defines carbon steel as non-alloy steel (Ref 13, pp. ATI 04 08). Such definitions are wrong because...