Post on 30-Apr-2020
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Infrared heat transfer for thin‐walled aluminium automotive castings – a novelty in the field of aluminium high pressure die casting demonstrating the high versatility of aluminium as all around
materialMarkus Belte & Dan Dragulin
BELTE AG
Delbrück
Belte AG Hauptsitz, Werk f. Wärmebehandlung
Altheim
Belte AG, Werk f. Wärmebehandlung
The use of infrared radiation in the field of aluminum processing enables easier automation and control of the heat transfer processes and contributes to productivity enhancement. The electrical hardware of the infrared module allows for drastic improvements in the efficiency factor of the industrial equipment used for aluminum processing, while also reducing the pollution degree.
Dr. Dimitrie Popescu, Associate Professor, Old Dominion University, Norfolk, Virginia, USA
Preamble
source:
Heraeus Noblelight
enables:
solution HT within the die or integrated in the HPDC‐cell
Basics of heat transfer
The application of infra‐red radiation to heat treatment of thin‐walled aluminium high pressure die castings is a process that is in the early stages of its development. The objective of the experiment presented in the paper was to analyze the heating rate of the casting and to study its corresponding mechanical properties. All experiments were realized using AUDI‐structural castings.Experimental conditions The casting process was performed by Trimet.IR Module
Ground coverage: 108 kWCastingWeight: 2.5 kgWeight of the zone under direct exposure to radiation: 1.5 kgSurface of the zone under direct exposure to radiation: 0.078 m² /side Wall thickness of the zone under direct exposure to radiation: 3 – 5 mm
experimental results
Fig. 1: Casting exposed to IR – between arrows the zone under direct exposure to radiation; distance casting – IR‐module: left: 10 cm ‐ right: 30 cm
experimental results
The figure (2) presents an inappropriate position of the casting within the IR‐module; this leads to a massive loss of the heating rate (see fig. 3) and as consequence to a corresponding reduction of the productivity.
experimental results
Fig. 3: Influence of various operating conditions on the heating rate – not coatedred: warm start in a encased module –3.39°C/s between 40°C and 470°Cgreen: warm start –2.39°C/s between 40°C and 470°Cblue: cold start –1.84°C/s between 40°C and 470°Cblack: cold start and a inappropriate position of the casting within the IR‐module –0.78°C/s between 40°C and 470°C
experimental results
Fig 4: Influence of the state of the surface on the heating rate[1]red: not coated – 2.85°C/s between 40°C and 470°Cgreen and blue: two different coatings – 3.84 respectively 3.94°C/s between 40°C and 470°C
[1] : warm start in a partially encased module
experimental results
Tab. 1: mechanical properties[1]
7.212.67.6At [%]
300214301Rm [MPa]
223120154Rp0.2 [MPa]
water coolingair coolingas cast
[1] heating regimes correspond to the red curve in fig. 4
Conclusion & prospectsThe obtained mechanical properties are more than encouragingThe design of the IR-module is very important for the optimization of the heat transfer process. Modern IR equipment can be adapted to the casting geometry.
Acknowledgement to: AUDI, Heraeus, LOI‐Italimpianti and Trimet.
experimental results
[1] T. Dulamita – Teoria si Practica Tratamentelor Termice, Ed. Tehnica Bukarest, 1966
[2] experimental results: . D. Dragulin, M. Belte – Infrared heat transfer for thin‐walled aluminium castings Aluminium Journal, 9/2013
[3] D. Frunzaverde – Tratamente Termice, Ed. Intergraf, Resita
Literatur