Description

Carbon structural steel grades: For example, Q235-A·F, indicates σs = 235 MPa. Grade annotation: Q represents yield strength, A is the quality grade (with four levels: A, B, C, and D), and F stands for boiling steel. Characteristics: Low cost, excellent process performance (such as weldability and cold formability). Applications: General engineering structures and ordinary mechanical parts. For instance, Q235 can be used to make bolts, nuts, pins, hooks, and less critical mechanical parts, as well as threaded steel, section steel, and reinforcing bars in building structures.

High-quality carbon structural steel grades: For example, 45, 65Mn, 08F. Grade annotation: Directly indicates the carbon content in parts per ten thousand. Applications: Non-alloy steels used for manufacturing important mechanical parts usually require heat treatment before use. Common steel grades and applications: 08F, with a low carbon content, good plasticity, and low strength, is used for stamping parts such as car and instrument shells; 20, with good plasticity and weldability, is used for parts with low strength requirements and carburized parts, such as engine covers, welded containers, small shafts, nuts, washers, and carburized gears; carbon steel 45, 40Mn, after quenching and tempering, has good comprehensive mechanical properties and is used for mechanical parts subjected to greater forces, such as gears, connecting rods, and machine tool spindles; 60, 65Mn steel has higher strength and is used for manufacturing various springs, locomotive flanges, and low-speed wheels.

Carbon tool steel grades: For example, T12 steel indicates carbon tool steel with Wc = 1.2%. Grade annotation: T plus the carbon content in parts per thousand. Characteristics: Belonging to eutectoid steel and hypereutectoid steel, with high strength, hardness, and wear resistance, suitable for manufacturing various low-speed cutting tools.

Common steel grades and applications: T7, T8: Used for parts that require toughness under certain impacts, such as sledgehammers, punches, chisels, woodworking tools, and scissors. T9, T10, T11: Used for tools with less impact and high hardness and wear resistance requirements, such as taps, small drills, dies, and saw blades. T12, T13: Used for tools that do not experience impact, such as files, scrapers, razors, and measuring tools.

Cast steel grades: For example, ZG200-400, indicates σs = 200 MPa, σb = 400 MPa cast steel. Properties: Poorer casting performance than cast iron, but better mechanical properties than cast iron. Applications: Mainly used for manufacturing complex-shaped, high-mechanical-performance mechanical parts that are difficult to form by forging and pressing processes, such as transmission cases for automobiles, couplers and couplings for locomotives and vehicles.