All Types of Steel

Carbon Steel
Carbon steel is an iron-carbon alloy. Its carbon content is less than 2%. It also has a small quantity of silicon, manganese, sulfur and phosphorus besides carbon. People always classify it for carbon structural steel, carbon tool steel and free-cutting structural steel by applications. And the carbon structural steel has two branches. They are building structural steel and structural steel for machine production. And also be divided into low carbon steel (ωc ≤ 0.25%), medium carbon steel (ωc = 0.25% - 0.6%) and high carbon steel (ωc > 0.6%). Usually, if the carbon content is bigger, then the hardness and strength also become higher. But the plasticity would get lower.Carbon Structural Steel
Usually, It does not through heat treatment. Just use it directly at the original factory status. And the Q195 steel, Q215 steel, Q235 steel have great welding performance, plastic nature and toughness. It always is used to make thin plates, steel bars, welded steel pipes. And the fittings of mechanical bolts, inside screws and etc. The Q255 steel and Q275 steel also have high strength, high plasticity, high toughness and can be welded very well. They are good material for gears, connecting bar and etc.Free Cutting Structural Steel
It is made by adding some elements which could make steel become brittle. Then the steel is easy to be cut during the processing. It is good for the efficiency of steel cutting and raises cutting tools useful time. And the main element is sulfur. However, people usually adding the lead, antimony and bismuth to the ordinary low-alloy free cutting structural steel. It's sulfur content is about 0.08%-0.30%. And the manganese element is 0.60%-1.55%. The sulfur and manganese are involved as the form of manganous sulfide. It has great lubricating efficiency to make the steel become easier to be processed.Alloy Steel
The steel must have the chemical element of iron, carbon, silicon, manganese, phosphorus, sulfur. But it also has some alloy elements. Such as silicon, manganese, molybdenum, nickel, chromium, vanadium, titanium, niobium, boron, lead and etc. Alloy steel is made by adding some alloy elements base on the common steel. And alloy steel can be divided into 8 groups: Alloy structural steel, Spring steel, Bearing steel, Alloy tool steel, High speed tool steel, Stainless steel, Silicon steel for electricians.