ASTM B917
Standard Practice for Heat Treatment of Aluminum-Alloy Castings from All Processes
Standard practice for the solution heat treatment, quenching, ageing and annealing of aluminum-alloy castings produced by any casting process, with recommended temperatures and times per alloy and temper.
What ASTM B917 specifies
ASTM B917 is the industrial practice for heat treating aluminum castings (sand, permanent mold, die, investment and other processes) and the technical counterpart of AMS 2771. Its tables recommend, per alloy and temper, the solution heat-treatment temperature and time — for example 356.0/A356.0 to T6 at about 1000 °F (540 °C) for 6–12 h, 355.0/C355.0 near 980 °F (525 °C) — the quench (water at 150–212 °F / 65–100 °C is permitted for castings, or glycol/polymer) and the ageing cycle (356.0-T6 at about 310 °F / 155 °C for 3–5 h; T7 stabilising ages at higher temperature), plus annealing (O/T2) and T5 (age from as-cast) treatments. It requires furnace uniformity of ±10 °F (±6 °C) at the solution temperature, limits the transfer time to the quench, defines heat-treat lots and reheat-treatment rules, and points to ASTM B557 tension tests and Brinell hardness (ASTM E10) as the means of showing that the casting specification (B26, B108, B85) properties were met.
Tests and the drawing call-out
Tests the document imposes
- Tension test per ASTM B557 on separately cast or excised specimens as the casting specification requires
- Brinell hardness per ASTM E10 (500 kgf / 10 mm ball)
- Furnace uniformity check (±10 °F) at the solution temperature
- Quench delay and quenchant temperature record
- Metallographic check for eutectic melting, blistering or excessive porosity when specified
How to cite it
Drawing call-out
HEAT TREAT PER ASTM B917 TO A356.0-T6; TENSILE PER ASTM B557 ON TEST BARS, HARDNESS PER ASTM E10Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
Heat treatments specified to ASTM B917
| Treatment | Role | Cost |
|---|---|---|
Age T6 (Aluminum) is a precipitation-hardening condition for 6061 and 6063 and 2024 and 7075. | Alternative | $$ |
Age T651 (Aluminum) is a precipitation-hardening condition for 6061 plate and 2024 plate and 7075 plate. | Alternative | $$ |
Age T73 (Aluminum) is a precipitation-hardening condition for 7075 and 7050 (alloy-specific overage condition). | Alternative | $$$ |
Aluminum O-temper annealing removes strain hardening and produces the softest standard wrought condition. | Related | $$ |
ASTM B917 — frequently asked
Which castings can be heat treated?
Those in heat-treatable alloys with a sound structure: 356/A356/A357 (Al-Si-Mg), 355/C355 and 319 (Al-Si-Cu), 201/206 (Al-Cu). Conventional high-pressure die castings in 380/383 are generally not solution treated because entrapped gas blisters near 950 °F; T5 ageing from the as-cast state is the usual limit for them.
How do T5, T6 and T7 differ for A356?
T5 is an artificial age straight from casting (no solution treatment) for a modest strength gain and dimensional stability; T6 is solution treat, quench and age for maximum strength (ASTM B26 sand-cast A356.0-T6 minimums are 34 ksi / 235 MPa tensile and 24 ksi / 165 MPa yield); T7 over-ages at a higher temperature for stability in warm service at some cost in strength.
Why a hot-water quench?
Castings have thin fins joined to thick bosses; a room-temperature water quench sets up thermal gradients that crack or warp them, while 150–212 °F water slows cooling enough to prevent that and still retains most of the strengthening solute. Polymer quenchants achieve the same effect.
What if the casting must be heat treated twice?
Reheat treatment is allowed under B917 within limits; each solution cycle risks blistering from gas porosity and coarsens the silicon, so the practice restricts repeats and requires the casting specification's properties to be verified again after the second cycle.
ASTM B917 is copyrighted by ASTM International. This page explains the document so a drawing can be read; it does not reproduce the standard. Purchase the current edition from the publisher. Official source ↗