SILAFONT® 36
ALSi10MnMg HPDC ALLOY
Silafont 36 is an AlSi10MnMg aluminium high pressure die casting alloy developed for demanding structural and automotive applications. It combines excellent castability with high ductility, good mechanical performance and a wide range of properties that can be adjusted through magnesium content and heat treatment.
In addition, Silafont 36 offers very good corrosion resistance, machinability and weldability. Therefore, the alloy is particularly relevant for complex HPDC components where structural performance, joining capability and lightweight design must be considered together. Furthermore, different treatment conditions allow engineers to balance strength and elongation according to the component requirement.
DUCTILE ALUMINIUM
FOR STRUCTURAL HPDC
Silafont 36 belongs to the low-iron Al-Si-Mg-Mn family of automotive casting alloys. Consequently, the alloy is designed not only for efficient die filling but also for demanding structural requirements after solidification.
For example, the as-cast F condition already provides a useful combination of strength and elongation. However, T4, T5, T6 and T7 treatments can shift the property profile toward higher ductility or higher strength. As a result, the same alloy family can support different component and crash-performance requirements.
SILAFONT 36
CHEMICAL COMPOSITION
The Silafont 36 chemical composition is based on the AlSi10MnMg alloy system with tightly controlled alloying elements. Silicon forms the largest alloying range, while manganese, magnesium, titanium and strontium are controlled within defined limits.
In particular, RHEINFELDEN ALLOYS specifies Silafont® 36 with narrow composition tolerances to support consistent casting quality. Furthermore, magnesium can be adjusted within its specified range according to the required mechanical property profile.
AlSi10MnMg
| Range | Si | Fe | Cu | Mn | Mg | Zn | Ti | Sr | P | Others |
|---|---|---|---|---|---|---|---|---|---|---|
| Minimum | 9.50 | – | – | 0.50 | 0.10 | – | 0.04 | 0.010 | – | – |
| Maximum | 11.50 | 0.15 | 0.03 | 0.80 | 0.50 | 0.07 | 0.15 | 0.025 | 0.001 | 0.10 |
Reference values for Silafont® 36 AlSi10MnMg in the ingot, expressed as mass / weight percent. Values marked with “–” indicate that no minimum content is specified in the referenced composition table. Always verify the current manufacturer specification for production and engineering decisions.
LOW IRON
CONCEPT
Iron is limited to a maximum of 0.15 %. Therefore, Silafont 36 belongs to the group of low-iron ductile aluminium die casting alloys described in the RHEINFELDEN technical documentation.
MAGNESIUM
VARIATION
Magnesium may vary between 0.1 and 0.5 %. In particular, this allows the chemistry to be selected according to the required strength, ductility and subsequent heat-treatment strategy.
STRONTIUM
MODIFICATION
Strontium is deliberately added to modify the eutectic silicon. Consequently, its controlled content is a defined feature of the Silafont® 36 specification.
Chemical composition is only the first part of the engineering picture. Next, the mechanical properties of Silafont 36 can be compared across the F, T5, T4, T6 and T7 treatment conditions.
VIEW MECHANICAL PROPERTIES ↓ SILAFONT 36
MECHANICAL PROPERTIES
The Silafont 36 mechanical properties can be adjusted over a broad range through magnesium content and heat treatment. Therefore, the alloy can provide either high ductility, increased yield strength or a balanced combination of both.
RHEINFELDEN ALLOYS specifies mechanical property ranges for the as-cast F condition as well as T5, T4, T6 and T7 treatment states. In particular, T6 offers the highest yield strength range, while T4 and T7 provide significantly higher elongation. Consequently, the final treatment strategy depends on the structural requirement of the component.
F
As-cast condition. Therefore, no additional solution or artificial ageing treatment is required after the high pressure die casting process.
T5
Quenched directly after removal from the die and artificially aged. As a result, higher strength can be achieved without conventional solution heat treatment.
T4
Solution treated, quenched and naturally aged for more than six days. Consequently, this state provides the highest specified elongation range.
T6
Solution treated, quenched and artificially aged. Therefore, T6 provides the highest specified yield-strength range for Silafont® 36.
T7
Solution treated, quenched and overaged. In particular, T7 combines lower strength with high elongation for applications where ductility is important.
STRENGTH, DUCTILITY
& HARDNESS
| Treatment | Yield Strength Rp0.2 [N/mm²] | Tensile Strength Rm [N/mm²] | Elongation A [%] | Brinell Hardness HBW |
|---|---|---|---|---|
| F · As-Cast | 120–150 | 250–290 | 5–11 | 75–95 |
| T5 | 155–245 | 275–340 | 4–9 | 80–110 |
| T4 | 95–140 | 210–260 | 15–22 | 60–75 |
| T6 | 210–280 | 290–340 | 7–12 | 90–110 |
| T7 | 120–170 | 200–240 | 15–20 | 60–75 |
T6
CONDITION
T6 provides a yield-strength range of 210–280 N/mm² and tensile strength up to 340 N/mm². Therefore, it represents the strongest specified treatment state in the current property table.
T4 & T7
CONDITIONS
T4 reaches 15–22 % elongation, while T7 reaches 15–20 %. Consequently, both conditions are relevant when high ductility is more important than maximum yield strength.
F & T5
CONDITIONS
The as-cast F state already provides useful mechanical performance. Furthermore, T5 can increase strength without a conventional solution-treatment route.
STRENGTH VS.
DUCTILITY
The Silafont 36 property profile follows a clear engineering trade-off. Higher yield strength is generally associated with lower elongation, whereas high elongation states provide lower strength. Therefore, no single heat-treatment condition is universally optimal.
Furthermore, RHEINFELDEN ALLOYS notes that the magnesium content should be adjusted to the required property profile. Consequently, alloy chemistry and heat treatment must be considered together when defining the target mechanical performance of a structural casting.
Mechanical properties are only one part of the structural design picture. Fatigue performance, corrosion resistance, welding, joining and real automotive component applications also influence the suitability of Silafont 36.
FATIGUE & CORROSION ↓ SILAFONT 36 FATIGUE
& CORROSION BEHAVIOR
Silafont 36 is used in structural applications where static strength alone is not sufficient. Therefore, fatigue behavior and corrosion resistance are also important when evaluating the alloy for automotive components.
In addition, published research has investigated the cyclic deformation and fatigue behavior of high pressure die cast Silafont® 36. Consequently, the alloy has become relevant not only as a casting material but also as a structural engineering material.
FATIGUE
STRENGTH
RHEINFELDEN ALLOYS reports fatigue testing on 4 mm high pressure die cast plates in the as-cast condition. The tests used fully reversed loading with a stress ratio of R = −1.
Under those conditions, the reported value corresponds to approximately 66 % of the yield strength. However, component geometry, casting quality, surface condition and load spectrum must also be considered in real engineering applications.
CORROSION
RESISTANCE
The manufacturer describes Silafont® 36 as having very good corrosion resistance. Furthermore, the documented corrosion behavior is comparable with that of a primary aluminium-silicon alloy.
The manufacturer documentation also reports no tendency toward stress corrosion cracking under the described material conditions. As a result, the alloy has been used for bodywork and chassis-related applications, including components without coating.
FATIGUE DATA REQUIRES COMPONENT CONTEXT
The 89 MPa value represents a documented material test under defined laboratory conditions and should not be interpreted as a universal component design limit. Instead, real structural validation must also consider casting defects, wall thickness, local stress concentrations, joining zones, heat treatment, surface condition and the actual load spectrum of the component.
In addition to fatigue and corrosion performance, processing and heat treatment strongly influence the final Silafont 36 property profile.
HEAT TREATMENT & PROCESSING ↓ HEAT TREATMENT
& HPDC PROCESSING
Silafont 36 heat treatment provides several routes for adjusting strength and ductility. Therefore, material chemistry, casting quality and treatment condition must be considered as one engineering system.
The manufacturer differentiates between treatments with and without solution heat treatment. Furthermore, air quenching can reduce the risk of dimensional distortion compared with water quenching in suitable processing routes.
F
As-CastThe component remains in the as-cast condition. Consequently, additional solution treatment is avoided and the dimensional state after casting is preserved.
T5
Direct Quench + AgeQuenching directly after removal from the die followed by artificial ageing can increase strength without a conventional solution-treatment process.
T4
Solutionized + Natural AgeSolution treatment and natural ageing produce a property profile with particularly high elongation. Therefore, T4 is relevant where ductility is a priority.
T6
Solutionized + Artificial AgeT6 combines solution treatment, quenching and artificial ageing. As a result, it provides the highest yield-strength range shown in the manufacturer property table.
T7
Ductility + Thermal StabilityOveraging shifts the property balance toward high elongation and thermal stability while maintaining higher strength than the high-ductility T4 condition in certain configurations.
EXCELLENT CASTABILITY
RHEINFELDEN describes Silafont® 36 as an aluminium pressure die casting alloy with excellent castability. Therefore, it is suited to complex high pressure die cast component geometries.
DISTORTION CONTROL
Air quenching after solution treatment can be used to reduce distortion risk. However, cooling rate, magnesium content and subsequent ageing must be coordinated with the required property profile.
STRONTIUM MODIFICATION
Manufacturer guidance emphasizes sufficient strontium modification to achieve a finely modified aluminium-silicon eutectic. Consequently, melt condition also influences the final ductility.
CHEMISTRY + PROCESS
+ HEAT TREATMENT
Silafont 36 does not have one fixed mechanical property profile. Instead, magnesium content and heat treatment can be coordinated according to the required balance between yield strength and elongation.
Consequently, treatment parameters should not be transferred blindly from one component to another. Casting geometry, wall thickness, porosity, dimensional tolerances and joining requirements must also be evaluated during component development.
After casting and heat treatment, joining technology becomes a decisive factor for structural automotive integration.
JOINING & MANUFACTURING ↓ SILAFONT 36 JOINING
& MANUFACTURING
Structural castings rarely function as isolated components. Therefore, Silafont 36 joining characteristics are particularly important for integration into aluminium and mixed-material vehicle structures.
RHEINFELDEN highlights weldability, machinability and compatibility with mechanical joining methods. In addition, adhesive connections can be considered within suitable automotive assembly concepts.
WELDING
Silafont® 36 is described by the manufacturer as very weldable. Therefore, the alloy can support aluminium profile-to-cast structural design concepts when the complete welding process is properly engineered.
VERY GOOD WELDABILITY SELF-PIERCING
RIVETING
Manufacturer documentation identifies suitability for self-piercing riveting and similar joining methods. High ductility is especially relevant because local deformation occurs during the joining process.
STRUCTURAL ASSEMBLY ADHESIVE
CONNECTIONS
Adhesive joining can complement mechanical or thermal joining in automotive body structures. Consequently, joint design may combine load transfer, sealing and multi-material assembly requirements.
HYBRID JOINING MACHINING
& FINISHING
Silafont® 36 is also described as very machinable and suitable for polishing. Therefore, functional interfaces and subsequent finishing operations can be integrated into the manufacturing route.
VERY GOOD MACHINABILITY DUCTILITY ENABLES
JOINING
Thin-wall structural castings require sufficient local ductility during several joining operations. For example, self-piercing riveting introduces significant local deformation into the casting.
Consequently, the combination of castability, elongation and joining performance is one reason ductile HPDC alloys such as Silafont 36 became relevant for automotive structural components.
These material and joining properties have enabled Silafont 36 to be used in a broad range of structural automotive applications.
AUTOMOTIVE APPLICATIONS ↓ SILAFONT 36
AUTOMOTIVE APPLICATIONS
Silafont 36 automotive applications include structural high pressure die cast components where castability, ductility, strength and joining performance must work together.
Manufacturer documentation and published automotive-material literature show applications ranging from shock towers and cross members to front-end and chassis-related structures. Therefore, Silafont® 36 represents an established example of a structural automotive HPDC alloy.
SHOCK
TOWER
RHEINFELDEN lists a Silafont® 36 high pressure die cast shock-tower application. This type of component combines complex geometry, structural load transfer and demanding integration into the vehicle body.
CROSS
MEMBER
Another documented application is a large high pressure die cast cross member. Consequently, the material is relevant not only for smaller brackets but also for comparatively large structural aluminium castings.
BODY-IN-WHITE
STRUCTURES
Published literature associates Silafont® 36 with front sections, space-frame elements, B-pillar reinforcement, hinge-pillar structures and other structural vehicle components.
CHASSIS
COMPONENTS
Literature also describes engine cradles, suspension-related structures, brackets and other load-bearing components. Therefore, fatigue resistance and joining behavior become important alongside tensile properties.
DOCUMENTED SILAFONT 36 APPLICATION LANDSCAPE
The combination of chemistry, mechanical properties, heat treatment, joining capability and automotive applications provides the complete engineering context for Silafont 36.
TECHNICAL FAQ ↓ SILAFONT 36
TECHNICAL FAQ
The following answers summarize the most important technical questions regarding Silafont 36 composition, properties, heat treatment, high pressure die casting and automotive structural applications.
What is Silafont 36?
Silafont® 36 is a low-iron aluminium-silicon-magnesium- manganese high pressure die casting alloy developed for demanding ductile and structural casting applications.
What is the Silafont 36 alloy designation?
Technical manufacturer documentation identifies Silafont ® 36 within the AlSi10MnMg alloy family and numerical material designation 43 500.
Can Silafont 36 be heat treated?
Yes. Depending on the required mechanical profile, Silafont 36 can be used in F, T5, T4, T6 and T7 conditions. Consequently, strength and elongation can be adjusted over a broad range.
Is Silafont 36 suitable for structural HPDC?
Yes. Documented applications include shock towers, cross members and other structural automotive castings. Furthermore, the alloy combines HPDC castability with useful ductility and joining behavior.
Is Silafont 36 weldable?
RHEINFELDEN describes the alloy as very weldable. In addition, manufacturer documentation identifies compatibility with self-piercing riveting and other automotive joining approaches.
Is Silafont 36 corrosion resistant?
The manufacturer reports very good corrosion resistance and no tendency toward stress corrosion cracking in the documented material evaluation.
What fatigue strength is reported for Silafont 36?
A manufacturer test on 4 mm as-cast HPDC plates reported 89 MPa under fully reversed loading at R = −1 and approximately 117 Hz. This value applies only to those specified test conditions.
Where is Silafont 36 used?
Automotive applications reported by manufacturer and technical literature include shock towers, cross members, engine cradles, front structures, suspension components and other structural body applications.
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