Mechanical forgings are forged to improve the structural and mechanical properties of the metal compared to castings. Due to the deformation and recrystallization of the metal, the original coarse dendrites and columnar crystals are transformed into an equiaxed recrystallized structure, and the crystal grains are fine and uniform in size. The original segregation, pores, pores and slag inclusions in the ingot have been compacted and welded, and the structure is more compact, and the plasticity and mechanical properties of the metal are improved.
The mechanical properties of castings are lower than mechanical forgings of the same material. Because the forging process can guarantee the continuity of the metal fiber structure, the fiber structure of the forging is the same as the shape of the forging, the metal streamline is complete, and the forgings produced by the process of precision die forging, cold extrusion and warm extrusion have good mechanical properties. And a long service life is not comparable to castings.
Mechanical forgings are objects that are plastically deformed into a desired shape or a suitable compressive force by plastic deformation. This force is usually achieved by using a hammer or pressure. The forging process establishes a fine grain structure that improves the physical properties of the metal. In practical applications, the correct design allows the particles to flow in the direction of the main pressure.
Castings are metal forming objects obtained by various casting methods, that is, molten liquid metal is injected into a pre-prepared casting mold by casting, injecting, suction or other casting methods. After cooling, objects of a given shape, size and properties are obtained by falling sand, washing and post-treatment.
In the production of mechanical forgings, in addition to the shape and size of forged parts, it is also necessary to meet the performance requirements of the in-use parts, including strength index, plasticity index, impact toughness, fatigue strength, fracture toughness and stress corrosion resistance, high temperature and high temperature. Instantaneous tensile properties, durability, creep resistance and thermal fatigue properties.