Possibilities of Pressure Die Casting of Iron Alloys

Abstract

The current trends of production of casts are directed towards production of components disposing of higher accuracy, increased quality of surface and homogenous structure. In case of a thin-walled cast the development of speed of pressing and of pressure was observed inside the mould cavity during pressure die casting of ferrous alloys. In case of die casting of ferrous alloys the attention was paid to life service of a pressing piston and of a filling chamber. The optimal temperature of the steel casting ranges from 1600 to 1750°C and optimal mould temperature ranged from 220 to 260°C. The residues having occurred in gates reached the hardness of 38 HRC and in case of casts the value was of 45 HRC. Influence of acting of resistance pressure on the thin-walled casts only minimally. With the increasing resistance pressure the structure becomes more fine-grained and along with the increasing thickness of the wall the influence of the resistance pressure increases as well. Technology of pressure die casting of iron alloys can be compared with the pressure die casting technology of aluminium alloys. As standard, for pressure die casting the cast irons with carbon content of lower than 3% are recommended.

Analysis of Selected Production Parameters for the Quality of Pressure Castings as a Tool to Increase Competitiveness

“…The presence of such internal stresses can negatively affect the mechanical properties of the castings and may result in subtle cracks or even casting failure. By addressing these factors and ensuring proper temperature control, mold surface insulation, and selection of greasing agents, manufacturers can minimize the formation of defects, internal stresses, and cracks, resulting in higher-quality castings with improved structural integrity [16,17].…”

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

“…Measuring the flow speed in the ingate has proved that the actual speed is only 30 to 50% of the calculated theoretical speed ]. 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.…”

“…Hardenability is assured by the existence of the Mg2Si or Al2Cu phase. The alloys in the injected and modified condition can reach ultimate tensile strength of over 300 MPs and they might be mechanically stressed at temperatures ranging from 250 up to 275°C [Ruzbarsky 2019a, Szymczak 2020b].…”

“…Throughout solidification, the metal remains under the pressure, i.e., the process is referred to as multiplication. High filling speed and high pressure allow the casting of thin-walled and rather fragmented castings, which in many cases do not require further machining other than the removal of sprues and fins [Caceres 1996, Ruzbarsky 2019a]. Die casting technology allows producing of castings with high complexity and surface quality approaching the final shapes and dimensions.…”

“…Not until the release of crystallization germs right above the fluid and the crystals of the solid phase between the liquid and the solid, do the alloys follow Newton´s Law. In the case of a mixture of solid particles floating in the fluid phase, the alloys follow the Bingham Law[Majernik 2016, Ruzbarsky 2019a]. In the interval of alloy crystallization, it is the case of two properties -viscosity and initial stress[Miglierini 2004].…”