Carbon steel is an iron-carbon alloy with a carbon content of 0.0218% to 2.11%. Generally, it also contains a small amount of silicon, manganese, sulfur, and phosphorus. Generally, the higher the carbon content of carbon steel, the greater the hardness and the higher the strength, but the lower the plasticity.
CLASSIFY
(1) Carbon steel can be divided into three categories: carbon structural steel, carbon tool steel and free-cutting structural steel according to its purpose. Carbon structural steel is further divided into engineering construction steel and machine-manufactured structural steel;
(2) According to the smelting method, it can be divided into open hearth steel and converter steel;
(3) According to the deoxidation method, it can be divided into boiling steel (F), killed steel (Z), semi-killed steel (b) and special killed steel (TZ);
(4) Carbon steel can be divided into low carbon steel (WC ≤ 0.25%), medium carbon steel (WC0.25%—0.6%) and high carbon steel (WC>0.6%) according to the carbon content;
(5) According to the quality of steel, carbon steel can be divided into ordinary carbon steel (higher phosphorus and sulfur), high-quality carbon steel (lower phosphorus and sulfur) and high-grade high-quality steel (lower phosphorus and sulfur). ) And super high-quality steel.
CATAGORY
1. Carbon structural steel
Grade: Example Q235-A·F, which means σs=235MPa.
Brand note: Q is the yield strength A quality grade (with ABCD four levels), F boiling steel.
Features: low price, excellent process performance (such as weldability and cold formability).
Application: General engineering structure and general mechanical parts. For example, Q235 can be used to make bolts, nuts, pins, hooks and less important mechanical parts, as well as rebar, section steel, and steel bars in building structures.
2. High-quality carbon structural steel
Grades: Example 45, 65Mn, 08F.
Brand note: It directly represents the ten-thousandth fraction of the carbon content of the metal.
Application: Non-alloy steel used to manufacture important mechanical parts is generally used after heat treatment.
Common steel grades and uses:
08F, carbon has low mass fraction, good plasticity and low strength, used for stamping parts such as automobile and instrument housing;
20. Good plasticity and weldability, used for parts with low strength requirements and carburized parts, such as hoods, welded containers, small shafts, nuts, washers, carburized gears, etc.;
45, 40Mn, good comprehensive mechanical properties after quenching and tempering, used for mechanical parts with greater stress, such as gears, connecting rods, machine tool spindles, etc.;
60, 65Mn steel has high strength; it is used to manufacture various springs, locomotive wheel flanges, and low-speed wheels.
3. Carbon tool steel
Grade: For example, T12 steel means carbon tool steel with Wc=1.2%.
Brand note: T plus the thousandth of the carbon content of the metal.
Features: It belongs to eutectoid steel and hypereutectoid steel, with high strength, hardness and good wear resistance. It is suitable for manufacturing various low-speed cutting tools.
Common steel grades and uses:
T7, T8: To produce parts that withstand certain impacts and require toughness. Such as sledgehammers, punches, chisels, woodworking tools, scissors.
T9, T10, T11: To manufacture tools that require high hardness and high wear resistance with less impact. Such as taps, small drills, dies, hand saw blades.
T12, T13: Make tools that are not impact-resistant. Such as files, scrapers, razors, measuring tools.
Cast steel
Grade: For example, ZG200-400, which means cast steel with σs=200MPa and σb=400MPa.
Performance: The casting performance is worse than cast iron, but the mechanical properties are better than cast iron.
Application: It is mainly used to manufacture more important mechanical parts that have complex shapes and high mechanical performance requirements, but are difficult to form by forging and other methods, such as automobile gearbox shells, rolling stock couplers and couplings, etc.