Generally, small and medium-sized forging parts use round or square bar as blank, bar grain structure and mechanical properties are uniform, good, accurate shape and size, good surface quality, easy to organize mass production, as long as reasonable control of heating temperature and deformation conditions, no large forging deformation can be forged with good performance.
Ingot is only used for large forgings. Ingot is an as-cast structure with large columnar crystals and loose ones. Therefore, it is necessary to break columnar crystals into fine grains through large plastic deformation and compact the loose ones in order to obtain good metal structure and mechanical properties.
The powder metallurgy preform formed by pressing and firing can be made into powder forgings without fly-edge die forging in the hot state. The powder powder is close to the density of general die forging, has good mechanical properties and high precision, which can reduce the subsequent cutting and manufacturing. The internal organization of powder forgings is uniform, without segregation, and can be used to manufacture small gear and other workpieces. However, the price of powder is much higher than that of general bar, and its application in production is limited.
By applying static pressure to the liquid metal poured into the die chamber, it solidifies, crystallizes, flows, deforms and forms under the action of pressure, and the die forging with the desired shape and performance can be obtained. Liquid metal die forging is a forming method between die casting and die forging. It is suitable for complex thin wall parts which are difficult to be formed by common die forging.
In addition to the usual materials for forging parts, such as carbon steel and alloy steel of various components, followed by aluminum, copper, titanium and their alloys, the deformation alloys of iron based superalloy, nickel based superalloy and cobalt based superalloy are also completed by forging or rolling. However, the forging difficulty of these alloys is relatively large due to the relatively narrow plastic zone. The heating temperature of different materials, There are strict requirements for open forging temperature and final forging temperature.