Forging is the forging of steel ingot into billet with hammer or pressure machine;According to the chemical composition, the steel can be divided into carbon steel and alloy steel

(1) In addition to iron and carbon, the chemical composition of carbon steel also contains elements such as manganese silico, sulfur and phosphorus, among which sulfur and phosphorus is a harmful impurity. Manganese silico is a deoxidized element added to carbon steel in the process of steelmaking. According to the different carbon content in carbon steel, it is usually divided into the following three types:
Low carbon steel: Carbon content is 0.04%-0.25%;
Medium carbon steel: 0.25%-0.55% carbon content;
High carbon steel: carbon content greater than 0.55%
(2) steel alloy is add one or several of alloying elements in carbon steel and tempered steel such steel contains both as silicon manganese alloy elements or solid elements, also contain other alloying elements, such as nickel chromium molybdenum vanadium titanium tungsten cobalt aluminum zirconium niobium and rare earth elements etc. In addition, some calcium alloy steel contains boron and nitrogen etc. Nonmetal elements according to the amount of the total content of alloy element in steel, is divided into the following three categories:

Low alloy steel: the total alloying element content is less than 3.5%;
Medium alloy steel: the total alloying element content is 3.5-10%;
High alloy steel: the total alloying element content is more than 10%
According to the number of different alloy elements contained in alloy steel, also can be divided into binary ternary and multi-element alloy steel in addition, according to the types of alloy elements contained in steel, can be divided into manganese steel, chromium steel, boron steel, silicon steel, manganese steel, chromium manganese steel, molybdenum steel, chromium molybdenum, tungsten vanadium steel and so on