The suitability of die cast parts for welding is highly dependent on the melt and pressure die casting process. It requires casting materials and melt and pressure die casting methods (see Vacural process, Vacuum systems by VDS SA Vacuum Diecasting Service) which ensure low gas absorption and oxide impurity during pressure die casting. The design engineer typically places weld seams in low-stress zones;...
Welded structures made of cast materials or mixed structures made of cast and wrought materials are state of the art, e.g. for the construction of light-weight chassis or large-scale structures in power installations. These structures utilize the combined benefits of casting technology, notably the freedom in design and the reliable production with welding. The physical, chemical and mechanical properties...
Precipitated silicon as the first phase in hypereutectic Al-Si alloys. During further cooling, the Al-Si eutectic solidifies and is called eutectic silicon. The primary silicon in hypereutectic Al-Si alloys (Si >12.5%) can form in various ways ( Figure 1 ). The morphology of the silicon depends on the solidification speed, the temperature gradient during solidification and the local chemical composition,...
Aluminum casting is the second most important cast construction material after cast iron. Table 1 (Aluminium Rheinfelden Alloys GmbH ) lists several decisive reasons for the great importance of the application of aluminum cast alloys as construction material. For production of castings, a wide range of standardized alloys as well as numerous special alloys are available to achieve the required properties....
If surfaces of liquid metals and alloys come into contact with atmospheric oxygen, they can be subject to the formation of thin oxide films. The risk of oxide film formation is even higher when the relevant metal or its alloy components exhibit a high degree of oxygen affinity. Insoluble oxide films are formed during melting, ladle filling and casting, in particular with aluminum, silicon and chromium as...
Aluminum alloys consist of aluminum (Al 99.5%) and other alloyed elements. It is essentially the following alloying element: Magnesium (Mg) Silicon (Si) Manganese (Mn) Copper (Cu) Zinc (Zn) The aim of alloying with the elements mentioned is to set the desired physical and mechanical properties for different delivery forms (e.g. profiles, bars, wire, strips, etc.) and casting processes (e.g. sand, die-cast...
For die castings which require high ductility, e.g. structural components in the car industry which require a high deforming ability in the case of a crash, the aluminum die casting alloys Al Si9Cu3(Fe) (VDS 226) or AlSi12(Fe) (VDS 230) which are otherwise frequently used are ruled out due to the low achievable elongation at failure ( The roll of the element iron in die casting alloys The element iron is a...
Modification of eutectic and nearly eutectic aluminum silicon die cast alloys (see also aluminum gravity die cast alloys) by adding weight loss and long-time resistant modification materials to the melt. Compared to fading sodium, the modification effect lasts for a longer period (in general 2 to 12 hours, see Fig. 1). Strontium is mainly used as permanent modification material. Mold foundries often add it...
Upon casting, the property profile of most aluminum (Al) casting alloys can be modified by heat treatment in a targeted manner. This applies to both sand and gravity die casting alloys and also to some pressure die casting alloys (in particular ductile die casting alloys). However, parts produced by conventional pressure die casting (without the use of a vacuum) are subject to limitations regarding solution...
Casting time diagrams and tables for aluminum, magnesium and zinc die casting alloys A casting time diagram established by F. C. Bennett – or H. H. Pokorny who slightly modified the casting time values determined by F. C. Bennett – is considered as particularly reliable. This casting time diagram is shown in Fig. 1 . Many authors determined the optimum casting time as a fraction of the solidification time...
Structural defect where the oxides in the casting are present as non-metal inclusions, usually in the form of thin, film-like skins. They are insoluble and cause local interruptions in the microstructure (see also Structural anomaly). As a result, they have a negative impact on static and dynamic strength characteristics and elongation ( Figs. 1 to 4 ). In highly vulnerable AlSi casting alloys (see also...
Formation of microscopic and macroscopic differences in composition in an otherwise homogenously structured alloy that consists of mixed phases. The solid phase that solidified first has a different alloy content as the residual melt. Accompanying and alloy elements considerably influence the segregation behavior. For example, this may lead to inclusions, carbide or structural degeneration at the grain...
Ductile aluminum die casting alloy for die castings with demanding requirements in terms of ductility and elongation at failure or with demanding requirements in terms of formability. An overview (without guarantee of completeness) of the alloys of this type and their chemical composition is given in Table 1 (Salzburger Aluminium Group). Alloy type Al Mg5Si2Mn The production of large structural parts with...
Almost circular pores with smooth-walled and blank inner surfaces, evenly distributed along a large cross sections ( Fig. 1 ). Gas pores must not be mistaken with rough-walled pores as a consequence of cavity formation (s. Cavities) . The defects preferably occur in metal alloys with large Soldification intervals, depending on the solidifcation characteristics (s. Solidification morphology) and are often...