The guardrail bracket is made of cast steel with carbon as the main alloying element and a small amount of other elements. Low carbon steel is cast with a carbon content of less than 0.2%, medium carbon steel is cast with a carbon content of 0.2% to 0.5%, and high carbon steel is cast with a carbon content greater than 0.5%. With the increase of carbon content, the strength and hardness of cast carbon steel increase. Cast carbon steel has high strength, plasticity, and toughness, and is low-cost. It is used in heavy machinery to manufacture parts that can withstand high loads, such as rolling mill frames and hydraulic press bases; Used in railway vehicles to manufacture parts that are subjected to high stress and impact, such as rocking pillows, side frames, wheels, and couplers.