Large scale machine tool castings are the core metal structural components in machine tool manufacturing, usually including bed, worktable, column, crossbeam and other components. They are the main structural supports of machine tools and directly affect the working accuracy, stability and service life of machine tools.

Material and Characteristics

Material:

Large machine tool castings mainly use high-strength gray cast iron (HT250-HT300), and some key components may use ductile iron or alloy cast iron. Gray cast iron has good wear resistance, shock absorption, and casting performance, which can withstand the vibration and impact of machine tool operation while maintaining structural stability.

Characteristics:

Wear resistance: The graphite structure in cast iron forms self-lubricating micropores, enhancing oil storage capacity and reducing wear.
Shock absorption: superior to steel, it can effectively absorb the vibration during machine tool operation and ensure machining accuracy.
Tensile strength: HT250-HT300 material has high tensile strength, extending its service life.
Thermal stability: After annealing, quenching and other heat treatment processes, the internal structure of the casting is stable, reducing the risk of deformation.

Manufacturing process

Casting process:

Resin sand casting: utilizing graphitization expansion to reduce shrinkage defects, achieving less or no riser casting, and improving material utilization.
Lost foam casting: It is formed by foam gasification and suitable for single piece or small batch production. It is characterized by high dimensional accuracy and small machining allowance.
Cupola casting: used for large-scale production, castings have no porosity, sand holes, or shrinkage porosity.

Heat treatment process:

Annealing: eliminates internal stress, improves toughness and tensile strength.
Quenching: Improve surface hardness (e.g. HT250 material can reach HRC46-50 hardness after quenching).
Tempering: Stabilize the structure, reduce brittleness, and prevent deformation or cracking.
Timeliness treatment: further eliminate internal stress and maintain structural stability.

Surface Treatment

Phosphating treatment: enhances rust prevention ability.
Room temperature blackening: improves corrosion resistance and decorative properties.
Coating process: including primer application, atomic ash filling, polishing and other steps to ensure surface smoothness and corrosion resistance.

Application Fields

Machine tool manufacturing:

The structural components such as the bed, columns, and beams, as well as the moving parts such as the worktable and slider, are all cast and processed to ensure the rigidity and stability of the machine tool.

Suitable for various types of machine tools such as gantry planers, lathes, milling machines, machining centers, etc.

Industrial equipment manufacturing:

Metallurgical equipment (such as high-temperature melting furnaces, continuous casting machines, rolling mills), mining equipment, energy equipment (such as wind turbines, hydroelectric generators, nuclear power equipment), etc., all require large castings as structural support.

Aerospace:

Key components such as engine parts, fuselage structural parts, landing gear, etc. have extremely high requirements for material strength, rigidity, and durability, and large castings can meet these needs.

Manufacturing of transportation vehicles:

Railway vehicle frames, ship hulls, automobile engine cylinders, etc. are cast and processed to ensure the safety and reliability of transportation vehicles.