A356 / EN AC-42100 Aluminium Investment Casting

A356 (ASTM B26) and EN AC-42100 – AlSi7Mg0,3 (EN 1706) are the most widely used aluminium alloys in investment casting. They combine good castability with useful strength after T6 heat treatment and low weight. BRK Metal casts A356 / EN AC-42100 in large volumes as a regular production alloy.

Designations and equivalents

Standard	Designation	Note
ASTM B26 / AA	A356.0	Low-iron version of 356
EN 1706	EN AC-42100 – AlSi7Mg0,3	European casting alloy
ASTM B26 / AA	356.0	Related alloy with higher permitted iron

Chemical composition (wt. %)

Element	A356.0 (ASTM B26)	EN AC-42100 (EN 1706)
Si	6.5 – 7.5	6.5 – 7.5
Mg	0.25 – 0.45	0.25 – 0.45
Fe	≤ 0.20	≤ 0.19
Cu	≤ 0.20	≤ 0.05
Al	balance	balance

Mechanical properties (T6)

Property	A356.0 – ASTM B26 T6	EN AC-42100 – EN 1706 T6
Tensile strength Rm	≥ 235 MPa	≥ 230 MPa
Yield strength Rp0.2	≥ 165 MPa	≥ 190 MPa
Elongation A	≥ 3.5 %	≥ 2 %
Hardness	—	≥ 75 HB

Values are minimums or ranges from the referenced standards for orientation; the current edition of the standard and your drawing requirements apply.

Typical applications

Lightweight housings and covers, brackets, firearm components, automotive and machinery parts, electrical equipment parts and other components where low weight matters.

Design and production notes

Heat treatment: T6 (solution treatment, quench, artificial ageing) is the usual condition for structural parts.
Weight: density about 2.7 g/cm³, roughly one third of steel.
Alternatives: EN AC-43000 (AlSi10Mg) is also a regular alloy at BRK Metal; other common investment casting aluminium alloys can be cast by project.
Finishing: machining and surface treatments on request.

More: aluminum investment casting, all material options, tolerances.

How to request a quote

Send a 2D drawing (PDF) and, if available, a 3D model (STEP), the alloy and condition you need, annual and per-order quantities, and any machining, coating or documentation requirements. Prices are calculated per part; the minimum order quantity depends on part size and geometry. Contact us to send your request.

FAQ

What is the difference between A356 and 356?

A356 has tighter limits on iron and other impurities than 356, which gives better ductility. Both are AlSi7Mg alloys.

What is the European equivalent of A356?

EN AC-42100 (AlSi7Mg0,3) according to EN 1706 is the usual European equivalent.

Why choose investment casting for A356 parts?

Investment casting gives thin walls, fine detail and good surface finish without draft angles, which reduces machining on complex aluminium parts.

Contact

You can contact us either by phone or by email. Our team will get back to you as soon as possible.