Basic Characteristics Of Cast Steel Components in Rail Transit

Material and Mechanical Properties
Material Type: Mainly cast carbon steel (such as ZG20-45#, ZG270-500) and low-alloy cast steel, with a carbon content usually between 0.2%–0.45%, and elements such as Cr, Ni, and Mo can be added to improve strength and toughness.

High Strength and High Toughness: Tensile strength can reach 500–700 MPa, and impact toughness ≥ 20 J/cm², suitable for withstanding high loads and impact conditions.

Good Isotropy: The internal structure of cast steel components is more uniform than that of forged steel, with smaller differences in three-dimensional mechanical properties, making it suitable for complex load-bearing structures.

Manufacturing and Process Characteristics
Capable of Forming Complex Structures: The casting process can manufacture complex-shaped components such as rocker beams, side frames, couplers, and bogie frames, reducing the need for welding.

Common Heat Treatment: Normalizing + tempering or quenching and tempering is often used to optimize the structure, relieve internal stress, and improve comprehensive performance.

Strict Quality Control: Requires ultrasonic testing (UT), magnetic particle inspection (MT), and low-magnification/high-magnification metallographic inspection to ensure there are no defects such as porosity, shrinkage cavities, or cracks.