Carbon steel, a material omnipresent in daily life and industrial fields, has a unique definition and rich connotations.
I. Definition of Carbon Steel
Carbon steel is an iron - carbon alloy with a carbon mass fraction of less than 2.11%, also known as plain carbon steel or carbon steel. During its production process, besides carbon elements, it generally contains a small amount of elements such as silicon, manganese, sulfur, and phosphorus. Among them, the carbon content has a crucial impact on the properties of carbon steel. Generally speaking, within a certain range, the higher the carbon content, the higher the hardness and strength will be, but the plasticity will be lower.
II. Classification of Carbon Steel
(A) According to the Purpose of Use
Carbon Structural Steel
This is the most common type of carbon steel, which can be further divided into engineering structural steel and machine - making structural steel. For example, its grade such as Q235 - A·F (where Q indicates that the yield strength is 235 MPa, A is the quality grade, with four levels of A, B, C, and D, and F represents rimmed steel). This type of steel is inexpensive and has excellent process properties, such as good weldability and cold forming property. In the construction field, it is used to make rebar, profiled steel, and steel bars for building structures. In mechanical manufacturing, it can be used to make bolts, nuts, pins, hooks, and some not - so - important mechanical parts.
Carbon Tool Steel
For example, T12 steel represents carbon tool steel with a carbon content of 1.2%. The grade of this type of steel is represented by "T" plus the thousandth of the carbon content in the metal. Such steels belong to eutectoid steel and hypereutectoid steel, and have the characteristics of high strength, high hardness, and good wear resistance. They are suitable for manufacturing various low - speed cutting tools and other tools. Steels like T7 and T8 can also be used to make parts that require certain toughness while bearing impacts.
Free - cutting Structural Steel
Specially used for manufacturing structural parts that can be relatively easily machined during the processing.
(B) According to the Smelting Method
It can be divided into open - hearth steel and converter steel. Different smelting methods will cause differences in the uniformity of the internal organization and impurity content of carbon steel.
(C) According to the Deoxidation Method
It can be divided into rimmed steel (F), killed steel (Z), semi - killed steel (b), and special - killed steel (TZ). Rimmed steel has a low production cost, but its internal organization is not dense enough; killed steel has a uniform internal organization and relatively stable properties.
(D) According to the Carbon Content
Low - carbon Steel (WC ≤ 0.25%)
Medium - carbon Steel (WC 0.25% - 0.6%)
High - carbon Steel (WC ≥ 0.6%)
(E) According to the Quality of Steel
It can be divided into ordinary carbon steel (with relatively high phosphorus and sulfur content), high - quality carbon steel (with relatively low phosphorus and sulfur content), advanced - high - quality steel (with even lower phosphorus and sulfur content), and ultra - high - quality steel.
III. Characteristics of Carbon Steel
Besides the characteristics brought about by the above - mentioned composition and classification, carbon steel also has good strength and rigidity. In terms of processing, it is relatively easy to carry out forging, welding, cutting, and other operations, which is also one of the reasons for its wide application in construction and mechanical engineering fields.
IV. Applications of Carbon Steel
In the construction field, such as constructing various building structures and bridges, providing necessary strength support for these buildings.
In the field of mechanical engineering, it is widely used in manufacturing automotive parts, various structural components of machines, etc.
In daily - life necessities, many tools are also made of carbon steel, which is an indispensable material in our lives.
In conclusion, with its rich types, diverse characteristics, and wide applicability, carbon steel plays an important role in numerous industries.