为什么选择灰铸铁？ — 铸铁平板的核心材料

Cast iron surface plates are fundamental equipment for key processes such as assembly, adjustment, welding, and riveting in the field of power machinery and equipment. Their work surfaces are typically equipped with T-slots for easy fixture and equipment mounting. These plates are mostly made of dense, stable gray cast iron or alloy cast iron, with a required work surface hardness generally between 170–220 HB.

So, why is gray cast iron commonly chosen as the raw material for these plates? The main reasons are as follows:

As foundational components with moderate material performance requirements, using gray cast iron for surface plates meets operational needs while achieving optimal economy. Gray cast iron is readily available and cost-effective, typically priced at only 60%–70% of cast steel, making it a highly cost-efficient engineering material. Accordingly, it has been specified as the primary material for such plates under the Chinese national standard GB/T 9439.

Although gray cast iron has low plasticity and toughness, its compressive strength is outstanding—generally three to four times its tensile strength—making it highly suitable for load-bearing components like machine tool bases and assembly plates. With a range of grades from HT150 to HT350, gray cast iron offers a good strength gradient to meet various load conditions.

Gray cast iron offers good castability and machinability, allowing easy shaping of castings and efficient subsequent machining. Moreover, the graphite within its structure helps absorb vibrations, giving the plates excellent damping characteristics that contribute to stability during processing.

Under lubricated conditions, the graphite on the surface of gray cast iron can form a lubricating film, effectively reducing the friction coefficient. When graphite micro-particles detach, the resulting pockets can store lubricating oil, continuously improving the working conditions of the friction pair and significantly enhancing wear resistance.