Author: Site Editor Publish Time: 2024-07-21 Origin: Site
Iron and steel materials is a general term for materials with iron as their main component, which, in addition to iron, consists of various elements such as C (carbon), Mn (manganese), and Si (silicon). By combining iron with other elements, various functional properties such as hardness and strength, flexibility and ease of processing can be obtained. Today, many steel materials with various elements added have been developed and manufactured and are used in many products around us.
Steel materials contain many different elements, the most common of which are C (carbon), Si (silicon), Mn (manganese), P (phosphorus) and S (sulfur). These elements are always mixed together when steel is made from iron ore and are known as the five basic elements of steel. Steel made from only these five basic elements is called carbon steel, with a carbon content (mass concentration) of 0.25% or less for low carbon steel, 0.25%-0.6% for medium carbon steel, and 0.6% or more for high carbon steel. The reason for the classification by carbon content is that the strength and toughness of materials vary greatly depending on the carbon content. Thus, carbon is the most important of the five elements.
On the other hand, materials to which one or more alloying elements are added to carbon steels to improve their properties are called alloy steels. There is a wide variety of elements that can be added, such as chromium (Cr) and nickel (Ni), and different properties can be obtained depending on the element added.
The following table compares carbon and alloy steels with a carbon content of about 0.45%.
S45C is a carbon steel with a C content of about 0.45%.
SCr 445 is an alloy steel in which S45C contains 0.9-1.2% chromium.
SCM 445 is an alloy steel containing 0.15-0.3% Mo in SCr 445
SCM 445 is an alloy steel containing 0.15-0.3% Mo in SCr445.
There are some differences in the content of C and Mn, but the composition of the five basic elements is generally similar.
Elemental contents (in mass percent)
Although the composition of the five basic elements is the same, the mechanical properties vary with the addition of new elements such as chromium and molybdenum, as shown in the chart below.
Mechanical Properties (JIS Reference Values)
In this way, the properties of steel materials change depending on the elements added. It is possible to manufacture high-performance steel materials by adding various alloys, but this also increases the cost, so when selecting materials in a design, it is important to consider the "balance" with the required performance.
