The Difference Between Squeeze Die Casting, Forging and Alloy Die Casting
Ⅰ. Introduction of the squeeze die casting
Squeeze die casting, also known as liquid die forging, continuous casting and forging, is a kind of newly developed metal forming technique with casting characteristics and similar to die forging. It is characterized by forcing a certain amount of molten metal under continuous mechanical static pressure into a pre-lubricated mold cavity. The fluidity of liquid metal and forging technology used during metal solidification forming process permit the plastic deformation of the solidified hard shell and the metal to crystallize and solidify under pressure. The shrinkage cavity formed by solidification shrinkage is forcibly eliminated, so as to obtain the liquid die forging parts without casting defects.
Ⅱ. Characteristics of the squeeze die casting compared with the forging
1. Generally, the mechanical properties of forgings are better than those of squeeze castings, but anisotropy commonly exists in forgings, especially the longitudinal plastic index is much higher than the transverse one, limiting the application of the forgings. Forgings have a slight advantage in terms of mechanical properties, however, the mechanical properties of squeeze castings can be improved to be close to or reach the level of forgings with proper technology and squeeze castings possess uniform properties in all directions;
2. Squeeze castings are formed by pressure acting on the liquid metal in the closed cavity to make it crystallize and solidify, while forging are formed by pressure acting on the solid metal;
3. Squeeze die casting is a kind of one-time metal forming process with high productivity, low labor intensity and low energy consumption;
4. Squeeze castings posses better surface finish and higher dimensional accuracy than forgings and investment castings, and the machining allowance is 0.5 to 2mm generally. Therefore, less metal materials are used and the cost is low. It is difficult for forgings to achieve the above dimensional accuracy and surface finish;
5. Squeeze die casting is suited for a variety of alloy materials, including cast aluminum alloy, zinc alloy, copper alloy, cast iron, cast steel and some deforming alloys, while forging materials are very limited.
Ⅲ. The difference between the squeeze die casting and alloy die casting
Sometimes we can't distinguish between squeeze die casting and alloy die casting and what's the difference? Firstly, squeeze die casting is a die casting method in which high pressure is applied to the liquid metal (or semi-solid slurry) in the mold cavity to destroy the growth of crystal dendrite and make the metal to feed under pressure, so as to obtain high-quality castings.
As a precise casting method, alloy die casting permits the die castings to have much smaller dimensional tolerance and higher surface accuracy. In most cases, die castings can be assembled and applied without turning, and threaded parts can also be cast directly. Small parts in security industry, vehicle industry, electronic products, decorations, as well as the complex parts of vehicles such as automobiles, locomotives and aircraft are mostly manufactured by alloy die casting method.