A356 aluminum: the short answer
What is A356 aluminum? A356 is an Al-Si7-Mg casting alloy, usually heat treated to T6. "A356-T6" on a drawing names the alloy and temper, but it is not a complete purchase specification: the order also has to name the governing standard, the heat-treatment condition and how the properties are tested.
- Name the standard, temper and specimen. State the governing standard with its edition (for example ASTM B26/B26M or ASTM B108/B108M), the temper, and where the test specimens come from. What to record on the drawing.
- A356.0 is the casting, A356.2 is the ingot. A356.2 has tighter limits, especially on iron. Say on the drawing which one you will inspect, and how. A356 vs A356.2.
- Typical is not guaranteed. The squeeze-cast A356-T6 values published on this site are a typical reference range, not minimums for your part. A356 composition and T6 properties.
- Choose the route by the part. Sealed housings such as motor housing castings (die casting) and leak-tested die castings are commonly die cast. When a structural part needs T6 strength and soundness, review A356-T6 squeeze casting capability.
- Next step. Send a drawing for DFM review with the material requirement. If the material is not settled yet, start with the aluminum casting RFQ checklist.
Who squeeze casts A356-T6 here
CEX Casting squeeze casts A356 and A356.2 aluminum and can combine it with in-house T6 heat treatment. The company has cast aluminum since 1995 and has run aluminum squeeze casting since 2019, in Jimo District, Qingdao, China (company-reported). The manufacturing entity is Qingdao Dechengxin Metal Products Co., Ltd., which holds the quality certificates in its own name.
Die casting or squeeze casting from the same supplier
CEX runs both routes: aluminum die casting on machines from 160 to 1,100 tonnes, and squeeze casting on machines from 300 to 1,100 tonnes (company-reported). Tooling for both processes is made in-house. The company operates three manufacturing bases in Jimo District, Qingdao. If you are not sure which route fits the part, ask in the RFQ for both routes to be considered before the process is fixed.
Start with the designation and the standard
An A356-T6 requirement names the governing material standard, the heat-treatment condition and how the properties are verified. "A356-T6" on its own is a grade name, not a purchase specification. For castings, the usual US references are ASTM B26/B26M (sand castings) and ASTM B108/B108M (permanent-mold castings); a squeeze casting is often ordered to one of them by agreement, or to a customer specification. State which one governs, with the edition, and confirm it in the quotation.
A356 and A356.2 are among the alloys we squeeze cast. Similar names in other systems, such as AlSi7Mg0.3 in EN 1706, are close but not interchangeable without a documented review.
CEX supplies aluminum and zinc components to industrial customers mainly in North America and Europe (company-reported). Whichever standard system your drawing uses, name one standard as governing in the order and treat any equivalent designation only as a cross-reference.
A356 vs A356.2
In the Aluminum Association system the suffix tells you the product form. A356.0 is the casting designation; A356.1 and A356.2 are ingot designations. A356.2 is the ingot with the tightest limits, particularly on iron, so that the casting made from it lands inside the A356.0 casting limits with margin after remelting picks up iron. In practice "A356.2-T6" on a drawing usually means a casting poured from A356.2 ingot and heat treated to T6.
| A356.0 | A356.2 | |
|---|---|---|
| Product form | Casting | Ingot |
| Chemistry checked on | The casting or melt | The ingot certificate |
| Iron limit | Casting limit | Tighter, to leave margin for remelting |
| On a drawing | Defines the delivered part | Defines the charge material; add the casting requirement |
If your drawing says A356.2, decide whether you are specifying the ingot, the casting, or both, and how each is evidenced: ingot certificate, spectrometer analysis of the melt, or both. We verify incoming ingot and the melt by optical emission spectrometer.
Typical vs guaranteed properties
Published A356-T6 values are typical: they describe what the alloy usually achieves in a test bar, not what your part is guaranteed to deliver. The figures we publish for squeeze-cast A356-T6 are a reference range of 260–320 MPa tensile and 220–260 MPa yield. Guaranteed minimums come only from the standard or specification you name, measured on the specimen type it defines, or from minimums agreed for your part with a defined specimen location.
| Typical value | Guaranteed minimum | |
|---|---|---|
| Source | Handbooks, supplier datasheets, our published reference | ASTM B26/B108 tables, customer specification, or agreed in the order |
| Specimen | Often not stated | Separately cast bar, cast-on, or cut from the part: named |
| Use | Feasibility and design screening | Acceptance of delivered lots |
A356-T6 squeeze casting: composition and published properties
A357 as the higher-strength option
A357 is the same Al-Si7-Mg family with a higher magnesium range (0.4–0.7% against 0.20–0.45% for A356) and tighter iron control, so it reaches higher T6 strength. We publish typical A357-T6 values of 275–310 MPa tensile and 230–280 MPa yield with 3–8% elongation. Choose it for structurally loaded parts that will be heat treated; expect it to machine harder and to need T6 or T61 to reach those values. The gravity-cast composition in ASTM B26 is tighter on iron, zinc and manganese than die-casting practice limits; quote the standard's limits if the drawing cites it.
Specify the finished component, not only a material label
| Requirement | What to record |
|---|---|
| Material | Exact designation and governing specification with edition |
| Condition | T6 (or T61), and any process constraints |
| Mechanical acceptance | Required properties, test method and minimum values |
| Specimen | Separate bar or cut from the part, with location and orientation |
| Dimensional acceptance | Drawing revision and the condition in which dimensions are checked |
| Records | Material identification, heat-treatment records, test reports |
Which certificates the manufacturer holds
The manufacturing entity behind CEX Casting is Qingdao Dechengxin Metal Products Co., Ltd., which holds the quality certificates in its own name. Its quality management system is certified to ISO 9001:2015 (certificate no. 08924Q53221R1S, valid until 2027-12-22). It also holds ISO 14001:2015 (no. 12425E00578R000) and ISO 45001:2018 (no. 12425S00499R000), both valid until 2028-05-11. Ask for the certificate copies with the quotation and check the validity dates against your delivery schedule.
What the IATF 16949 certificate covers
The IATF 16949:2016 certificate (no. 0494978, valid until 2027-01-07) has the scope "manufacturing of aluminium alloy die-cast parts", with clause 8.3 product design excluded. The scope names die-cast parts; it does not name squeeze casting. If your automotive program requires IATF 16949 coverage for an A356-T6 squeeze-cast part, raise it at the RFQ stage and agree in writing how the part will be handled.
Why the specimen matters
A result needs enough context to connect it to the component. Ask where the specimen comes from, which lot it represents and which test method was used. If the application needs properties in a critical section, state that explicitly; a separately cast bar does not represent a thick boss in the part.
Plan heat treatment and machining together
Decide when critical bores, sealing faces and datums are machined relative to T6, and in which condition the final dimensions are checked. Heat treatment and machining are both in-house, so the route is confirmed against the material and the geometry together.
Material: A356.0-T6 per ASTM B108/B108M-[edition], cast from A356.2 ingot. Tensile ≥ [ ] MPa, yield ≥ [ ] MPa, elongation ≥ [ ]% on specimens [cut from zone X / separately cast], per ASTM B557. Hardness [ ] HB at location [ ] after T6. Dimensions verified after heat treatment and machining.
The bracketed values come from your design; we do not prefill them.
T5 and T6 qualification Specifying mechanical properties
How T6 parts are checked for soundness and leaks
T6 heat treatment is done in-house, and two inspection methods are available for internal soundness and pressure tightness (company-reported). X-ray inspection checks the internal soundness of castings against acceptance criteria agreed for the part. Helium leak testing is available for parts that must be pressure-tight. Put the X-ray acceptance criteria and the leak-test requirement on the drawing or in the order. Published A356-T6 values of 260–320 MPa tensile and 220–260 MPa yield are reference values, not acceptance criteria.
A356 aluminum at a glance
A356 is an Al-Si7-Mg casting alloy, close to AlSi7Mg0.3 in EN 1706. It contains 6.5–7.5% silicon and 0.20–0.45% magnesium and is usually heat treated to T6. For squeeze-cast A356-T6 we publish 260–320 MPa tensile and 220–260 MPa yield as typical reference values, not guaranteed minimums.
A356 chemical composition
| Element | A356 (%) | A356.2 (%) |
|---|---|---|
| Silicon (Si) | 6.5–7.5 | Tighter window; limits per the ingot standard named in the order |
| Magnesium (Mg) | 0.20–0.45 | As above |
| Iron (Fe) | ≤ 0.2 | Tighter than A356 |
| Copper (Cu) | ≤ 0.2 | As above |
| Manganese (Mn) | ≤ 0.1 | As above |
| Zinc (Zn) | ≤ 0.1 | As above |
| Titanium (Ti) | ≤ 0.2 | As above |
| Aluminium (Al) | Balance (91.1–93.3) | Balance |
A356-T6 properties
| Property | A356, range across tempers | Squeeze-cast A356-T6, typical | A357-T6, typical |
|---|---|---|---|
| Tensile strength | 207–310 MPa | 260–320 MPa | 275–310 MPa |
| Yield strength (0.2%) | 138–228 MPa | 220–260 MPa | 230–280 MPa |
| Elongation | 3–10% | Not yet published | 3–8% |
| Hardness | 70–80 HB | Not yet published | — |
| Density | 2.68 g/cm³ | 2.68 g/cm³ | 2.68 g/cm³ |
| Melting range | 570–580 °C | Same alloy | — |
| Thermal conductivity | 151 W/m·K | Same alloy | — |
| Thermal expansion | 21.4×10⁻⁶/°C | Same alloy | — |
Squeeze casting capability for A356-T6 Casting weight calculator
A356 or A357: quick selection
| Question | A356 / A356.2 | A357 |
|---|---|---|
| Magnesium | 0.20–0.45% | 0.4–0.7% |
| Iron control | A356.2 tighter than A356 | Tighter |
| Typical use | Pressure-tight and general structural parts in T6 | Structurally loaded parts that need higher T6 strength |
| Machining | Baseline | Machines harder |
| Heat treatment | T6 (or T61) | T6 or T61 to reach published values |
Casting capabilities Alloy selection for pressure-tight parts T5/T6 heat-treatment qualification Specifying mechanical properties on castings
What size of A356-T6 squeeze casting can be made
Squeeze-cast parts in A356-T6 are made from 50 g to 20 kg, within a maximum part envelope of 1.2 × 0.8 m, on squeeze casting machines from 300 to 1,100 tonnes (company-reported). The weight range is evaluated against each part's geometry and project requirements. As-cast blank tolerance is ±0.2 mm; tolerances on machined features are agreed feature by feature. The squeeze casting tooling is made in-house.
Published A356.2-T6 squeeze casting examples
Three published examples show where squeeze-cast A356.2-T6 has replaced another process (company-reported). A trailer bracket that was a sand casting is weldable and showed about 50% higher strength. A boat part that replaced a conventional aluminum high-pressure die casting showed at least 50% higher strength. A trailer connector that replaced a steel casting was at least 54% lighter. These results belong to those parts and are not values for a new design.