Die casting is an economic way of producing large quantities of complex parts and high tolerance in aluminium, magnesium, zinc and copper alloy. The continued and sustainable growth of die casting is due in large part to the increased use of casting parts into the automotive industry, where concern about weight reduction has gained increasing importance.
The production of increasingly longer series also determines greater attention in the design of the mould, including the selection of the most suitable steel. Mould makers, with the right choice of high quality and high performance steel, can achieve considerable cost reductions in tool manufacturing. It is possible to further optimize moulds with greater care in the design of casting parts, project of moulds and good manufacturing practices.
In the forge, the billet is pressed into a forging die to obtain an almost finished part. A large number of solid metal parts are produced in aluminium alloys, copper alloys, steel or super alloys, with irregular shapes and good mechanical characteristics. The main methods of forging are hammer and press forging.
The requirements of extrusion on the tool steel depends mainly on the working temperature, the material to be extruded, the location of the component in question with respect to the heated billet and the output of the extruded profile.
The most demanding component, either thermally or mechanically, is, undoubtedly, the die. The other components such as the liner, or dummy block and, where it is used, the chuck, are subject to high temperatures.
The most typical working temperatures are:
Aluminium and aluminium alloys: 400 - 600ºC
Copper and copper alloys: 600 - 1000ºC
Steel: 1100 - 1250ºC
A correct choice of steel as well as a correct heat treatment are essential to increasing the life of the extrusion dies and their components.