The Impact of Technological Parameters of Die Casting to Casting Porosity

Abstract

The authors within the scientific contribution present the logistics of laboratory experimenting with strengthening the stressed surface layers of machine parts. The project for strengthening the surface layers was conducted without the use of ultrasonic strengthening via the newly developed device with a static pressing force. Emphasis was placed on the stage of identification of samples surface layers, their microstructure, roughness and hardness after lathe turning and shot peening as well as on the wear of the used forming element after shot peening. The process of experiment results in the modelling of technological conditions and parameters of a newly-designed and verified technology with formulating the logistics steps for practical use. Logistics can be seen, in addition to a structured arrangement of relationships and activities, as a control system process able to efficiently use available resources in terms of time and value within the various activities at the lowest costs incurred.

Properties of alloys in the crystallization interval

“…It is possible to reach thus that undercooling the cast alloy in the crystallization interval against the liquids does not overcome the stated limit. From the experimental results (Majerník and Ružbarský, 2016) follows that the admissible limit at aluminum alloys is…”

Influence of Die Casting Speed on Properties of Casting Based on Al-Si Alloys

“…In the mould cavity the values of metal flow speed range from 5 to 15% of the theoretically calculated flow speed of alloy [Ragan 2007, Ruzbarsky 2019b]. The actual molten metal flow speed is affected mainly by the following [Majernik 2016]: • viscosity of alloy depending also on its temperature, • losses caused by friction in the gating system and a mould cavity, • losses caused by the change of the melt flow direction in the gating system and the mould cavity, • pressure of air and vapours in the mould cavity moving against the molten metal flow. The speed of the melt flow also affects the mechanical properties of the casting and the inner and surface quality of castings.…”

“…Selection of the right speed of the mould cavity filling depends on the alloy type, the casting complexity, the wall thickness, and the ratio of the gate area and the area of casting. The dependence of optimal speed in the ingate on the wall thickness and on the length of casting is shown in Figure 1 [ Majernik 2016, Silmbroth 2020]. The character of the melt flow in the mould cavity depends on input melt speed into the mould cavity, mutual relation of the ingate thickness and the casting or their areas, viscosity and surface tension of the melt, and thermal conditions which are formed due to reciprocal influence between the melt and the mould.…”

“…Theoretically, the mould cavity filling time can be calculated as follows , Gaspar 2016a: In the case of constant thermal and physical characteristics, it has been proved in the experiments that filling time depends on the casting wall thickness and is independent of its dimensions as it is shown in Figure 2 [Caceres 1996, Cao 2017, Ragan 2006]. Optimal mould cavity filling time about the casting wall thickness can be expressed by the following empirical relation [Majernik 2016]: 𝜏 = 1.6. 10 −2 .…”

Possibilities of Pressure Die Casting of Iron Alloys

“…At the same time it can be assumed that ferrous alloy processed by the aforementioned technology could replace other steels in a number of spheres. To clarify the aforementioned objectives the experimental tests of pressure die casting of ferrous alloys were performed [12,17].…”