The material presented in this video are some highlights from the North American Die Casting Association’s online webinar, "High Integrity Die Casting: Melting, Melt Treatment, and Transfer for High Integrity Die Casting."
In this webinar best practices of melting, melt treatment and transfer for aluminum high integrity die casting of structural components will be presented and discussed. Many oxide and other inclusions originate from inappropriate practices with the liquid aluminum before it is cast. They cause quality issues / high scrap rates and reduced properties. This webinar explains how to avoid them by using best practices like filtering, degassing, fluxing, skimming, settling, quiescent transfer, etc.
For information on purchasing a downloadable copy of this webinar in its entirety, please visit: http://www.diecasting.org/store/detail.aspx?id=WEB144
(Transcript of the highlight.)
"All these inclusions are causing us a lot of problems. What are the detrimental effects of them?
Well, first of all, they reduce machineability. They cause pretty high tool wear. They cause increased porosity because they are nucleation points. They also cause reduced foundry fluidity, and that's really bad if we wanted to cast a large casting with a 2 millimeter wall thickness. It can be even a possible blockage, so we can't feed anymore and then behind that blockage we will just create a void.
Therefore, we need filtering, we need degassing, fluxing, and skimming, don't forget. We want to take it out and then settling. Some people might work with troughs to transfer the metal from melting to dousing, and that's not a bad thing. That's a good thing if you use it properly because heavier particles will just settle down because of the difference in density."
To purchase access to this course, visit the NADCA Marketplace at www.diecasting.org/store. Purchasing a course through the online education system grant you one year of access to the recording, presentation, support material, and test when applicable.
NADCA Congress Session Spotlight - Cast Materials: Aluminum
In the weeks leading up to the 2018 Die Casting Congress & Exposition we will be highlighting information on papers that will be presented during the congress sessions. The following papers are scheduled to be presented on Tuesday, October 16:
Cast Materials: Aluminum: 9:45 am - 11:15 am
Session Chair: Frank Goodwin
HP-DC Alloys for Structural Castings: AlMg4Fe2 and AlMg4Zn3Fe2 (Castaduct-42 and -18)
Stuart Wiesner, Fabian Niklas (Rheinfelden Alloys); Richard Alan Miller (Nikkei MC Aluminium America)
AlMg4Fe2 and AlMg4Zn3Fe2 (Castaduct-42 and -18) are two alloys recently developed by Rheinfelden Alloys. They are dedicated for high pressure die cast structural parts for automotive car bodies.
AlMg4Fe2 (Castaduct-42) relies on a eutectic composition formed by a combination of around 4,2 % Mg and around 1,6 % Fe. This guarantees very good castability which is similar to Al-Si alloys. Si is restricted to a minimum level. In the absence of Si, Fe is an alloying element and does not negatively impact the properties. This alloy fulfils the requirements for structural parts without any heat treatment and has been tested by several foundries and OEMs in North America and Europe.
AlMg4Zn3Fe2 (Castaduct-18) is a further development of AlMg4Fe2. This alloy provides higher strength making it one of the highest strength HP-DC alloys for structural parts currently available. Due to its cold hardening behavior, AlMg4Zn3Fe2 offers yield strength values up to 180 MPa in as cast state while still having 7% elongation. These values were achieved in first casting trials by an Italian foundry.
Mechanical properties, metallurgy investigations, chemical attack against die steel, fatigue strength, static and dynamic 3-point bending test, corrosion trials and joining techniques such as riveting and welding are discussed.
A New High Performance HPDC Aluminum Alloy
Xinyan Yan, Francis Caron (Alcoa Technical Center)
Continuous demands of light-weight and cost reduction in automotive and other industries have resulted in increasing needs for high performance aluminum foundry alloys. An Al-Si-Mn-Mg based new foundry alloy was recently developed to meet such needs. The new alloy is targeted for thin-wall high pressure casting application, thus has a very good fluidity, good hot cracking resistance and excellent die soldering resistance. After T6 heat treatment, the new alloy can achieve 300MPa yield strength and 8% elongation. The mean fatigue strength of this alloy improved more than 20% when compared to the incumbent high pressure die cast aluminum alloy, 365-T6. Weldability test and corrosion tests, including ASTM G110 type of attack test and ASTM B117 cyclic salt spray test, were also conducted. Results indicate that the new alloy is weldable to 6082-T6 extrusion and welding does not appear to degrade the corrosion performance of the new alloy.
Formation of Ring-Like Inhomogeneous ESCs Bands in High Pressure Die Cast A390 Alloy
Shoumei Xiong, J. Wang, S .M. Xiong (Tsinghua University)
Ring-like inhomogeneous ESCs band was observed in high pressure die cast A390 hypereutectic alloy and different microstructures such as pores, externally solidified crystals(ESCs) of primary silicon particles(PSPs) and Cu-rich phases in the standard die casting bar were characterized by synchrotron X-ray tomography. The distributions and amount of PSPs, pores and Cu-rich phases varied from the outer part to the inner part of the standard bar. The ring-like bands consist of a series of PSPs-free zone and PSPs-rich zone in the optical micrograph. The near the surface band was a PSPs-free zone followed by a layer of PSPs-rich zone. Between the first PSPs-rich zone and the center PSPs rich zone, there exists a new PSPs-free band with an abrupt increase of both porosities and Cu-rich phases compared to the first PSPs rich zone. Besides, the porosities in the new PSPs free zone also exhibit a ring-like distribution similar to the defect band of porosity.
The NADCA Housing Block is closing September 25! Please make sure to make your hotel reservations. NADCA’s host hotel, the Indianapolis Marriott Downtown, is already sold out. There are still plenty of rooms available in NADCA’s room block at various hotels throughout the city. Click here to make your reservation now.
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