Study of the Effect of Surface—Roughness of Dies and Tooling for HPDC on Soldering

Gobber, Federico Simone; Pisa, Andrea Giuseppe; Ugues, Daniele; Lombardo, Simone; Fracchia, Elisa; Rosso, Mario

doi:10.1007/978-3-319-72284-9_127

Cited by 4 publications

(5 citation statements)

References 21 publications

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“…Alloys were molten in graphite crucibles and cast by gravity-casting method into a preheated mould opportunely painted with a BN-stop-off paint [23,24]. The stop-off paint acts by reducing thermal stresses and contact with molten aluminium alloy and the steel mould [25,26]. In Figure 2, the casting sequence is shown: Alloys were melted into a graphite crucible and then poured into the mould.…”

Section: Methodsmentioning

confidence: 99%

Effects of Casting-Additives on the Microstructure Evolution of Hypoeutectic Aluminium-Silicon Alloys

Fracchia¹,

Gobber²,

Rosso

2020

Metals

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Since the industries are called to produce environmentally friendly products, the research is moving toward new improved materials. In this panorama, aluminium alloys find applications for a large range of products. In the automotive, as well as in the aerospace, sector, aluminium alloys are largely adopted, thanks to their high specific properties and their light weight. Moreover, common casting techniques permit us to realize complex high-quality components. These components may be realized by using casting techniques adopting casting-additives, such as modifiers or refiners. In this work, the effect of refining and modification was studied in terms of microstructural evolution of the intermetallic phases in two aluminium-silicon alloys (EN AC 45300 and EN AC 43500). Microstructures were analyzed through micro-hardness measures, and we found a reduction in the standard deviation of the hardness with the addition of additives. Furthermore, secondary dendrites arms spacings (SDAS) were measured, evidencing a decrease in SDAS by adding casting additives. A strong correlation was found between the adding of additives and the possibility of containing the size of the silicon and of all the intermetallic phases opening up to the possibility of tailoring the microstructures.

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Section: Methodsmentioning

confidence: 99%

Effects of Casting-Additives on the Microstructure Evolution of Hypoeutectic Aluminium-Silicon Alloys

Fracchia¹,

Gobber²,

Rosso

2020

Metals

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“…Cast alloy soldering is a process in which molten reacts with die material and forms strong bonds between the casting and die material. As a consequence of the soldering process upon the casting ejection, thin layers of cast alloy remain on die surfaces [3]. This leads to the reduction of castings quality, decreased productivity, and increased production cost due to increased machine downtime [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

The Influence of CrAlN Coating Chemical Composition on Soldering Resistance in Contact with Al-Si-Cu Alloy

Kukuruzović¹,

Terek²,

Kovačević³

et al. 2020

2nd Coatings and Interfaces Web Conference (CIWC-2 2020)

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During the high pressure die casting (HPDC) process the die material is exposed to thermal fatigue, erosion, and corrosion. Corrosion leads to the soldering of cast alloy to tool surfaces which consequently bonds the casting with die material. Besides wear, such a process reduces the casting quality and production efficiency and endangers the tool integrity. Application of thin ceramic coatings on die surfaces reduces the soldering effects and improves the die performance. However, the development of ceramic coatings for these purposes still requires detailed information on the phenomena involved in these processes. In this study, the soldering performance of a complex nanolayer CrAlN coating, with three chemical compositions (high-Cr, balanced Cr:Al, and high-Al content) were evaluated. The cast alloy soldering was evaluated by the detachment test in three configurations. In this test, a simple casting is formed in contact with flat coated surfaces. Upon casting solidification, the formed joint is dismantled, and a force required for this process was recorded. To characterize and quantify the exhibited wear, after the detachment test, surfaces of the coated samples were analyzed by different microscopy techniques. Two forms of wear were detected on investigated samples. Cast alloy soldering processes induced the formation of thin layers of cast alloy on the surfaces of all investigated coatings. Additionally, substrate corrosion through the coating growth defects caused coating layer delamination during the detachment test. The evaluated coatings displayed different behaviors regarding the extent of wear and values of the detachment force. The coating with a balanced CrAlN composition exhibited the best soldering and corrosion resistance and displayed the lowest ejection force. In terms of soldering and corrosion resistance, the high-Al coating outperformed the high-Cr content coating. However, high-Al and high-Cr coating exhibited significantly higher and quite comparable values of detachment force. Based on the quantitative results it was postulated that, besides soldering and substrate corrosion, the casting-coating bonding strength depends also on “pure” sticking effects of cast alloy to coated surfaces.

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“…Despite the application of lubricants to favor the detachment of the cast once solidified, adjusting the spraying regime (location of sprayers, spraying time, and pressure) is not a simple achievement especially for complex geometry cavities. In this regard, the relationship between the die surface finishing, the ability to retain the lubricant, and subsequent metallization is a topic poorly studied . The damaging mechanisms discussed earlier are related to the operative conditions of the die and the different factors interacting during the die‐casting process.…”

Section: Introductionmentioning

confidence: 99%

“…Low cycle fatigue (LCF) with relation to the die‐casting process has been studied in depth and modeled, among others, by Rézaï‐Aria and coworkers, who developed a specific test rig where internally cooled tool steel samples are heated through an induction coil . In contrast, soldering has been approached historically as a problem of chemical interaction between aluminum alloy and steel; in the past years more quantitative approaches involving the use of test rigs to simulate the aluminum/die interaction were proposed to characterize the effect of surface treatments . Test rigs where die samples are alternatively dipped into a molten aluminum alloy and into a cooling bath are developed, but these studies rarely quantified the stresses acting on samples and the deriving LCF loops .…”

Section: Introductionmentioning

confidence: 99%

Design of a Test Rig for the Characterization of Thermal Fatigue and Soldering Resistance of the Surfaces of Tool Steels for High‐Pressure Die‐Casting Dies

Gobber

Pisa²,

Ugues

et al. 2019

steel research int.

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The conceptualization and development of a test rig able to reproduce thermal stresses and contact with molten aluminum alloy, typical of high-pressure diecasting dies, are described. During the test, a hot-work tool steel sample is cyclically heated by contact with molten aluminum alloy (AlSi11Cu2(Fe)) and then cooled by the spraying of a water-diluted silicone-based lubricant. A finite element method (FEM) simulation is setup to determine the temperature at different depths beneath the sample surface during thermal cycling and is experimentally validated to design the proper sample geometry aimed at reproducing the stress/strain conditions experienced by a die-casting die insert. A tensile-compressive stress state is achievable on the surface of the sample by machining a notch with a suitable radius, which is able to produce a plastic strain comparable with the insert one. A thermally induced stress-strain fatigue loop is determined for both the sample and the component. Temperatures are monitored discontinuously by infrared (IR) thermography after heating and continuously by thermocouples placed at a reference depth of 5.5 mm. Finally, the optimized testing conditions are validated experimentally: both thermal cracking and soldering phenomena are successfully reproduced on a lab-scale test rig.

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Study of the Effect of Surface—Roughness of Dies and Tooling for HPDC on Soldering

Cited by 4 publications

References 21 publications

Effects of Casting-Additives on the Microstructure Evolution of Hypoeutectic Aluminium-Silicon Alloys

Effects of Casting-Additives on the Microstructure Evolution of Hypoeutectic Aluminium-Silicon Alloys

The Influence of CrAlN Coating Chemical Composition on Soldering Resistance in Contact with Al-Si-Cu Alloy

Design of a Test Rig for the Characterization of Thermal Fatigue and Soldering Resistance of the Surfaces of Tool Steels for High‐Pressure Die‐Casting Dies

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