Process for low-cost tempering of aluminum casting

A method of manufacturing a cast aluminum alloy, comprising the steps of:

• casting an aluminum alloy, the aluminum alloy including silicon in an amount of 4.0 to 9.0 weight percent (wt. %), copper in an amount up to 0.10 wt. %, iron in an amount up to 0.25 wt. %, manganese in an amount of 0.3 to 0.60 wt. %, magnesium in an amount of 0.10 to 0.60 wt. %, titanium in an amount up to 0.15 wt. %, strontium in an amount of 0.01 to 0.6 wt. %, and a balance of aluminum, except for possible incidental elements and/or impurities, based on the total weight of the aluminum alloy;
• applying a coating to the cast aluminum alloy;
• heating the coated cast aluminum alloy;
• wherein the cast aluminum alloy has an F temper designation before the heating step and the cast aluminum alloy has a T85 temper designation after the heating step, and
• wherein the cast aluminum alloy has a yield strength (YS) ranging from 90 to 200 MPa, an ultimate tensile strength (UTS) ranging from 220 to 300 MPa;
• and an elongation percentage (%) of 7.0% to 19% prior to the heating of the cast aluminum alloy when tested according to an ASTM E8 specification;
• and the cast aluminum alloy has a yield strength (YS) ranging from 100 to 220 MPa, an ultimate tensile strength (UTS) ranging from 230 to 320;
• and an elongation percentage (%) of 6.0% to 15% after the heating of the cast aluminum alloy, wherein the heating step includes curing the coating on the cast aluminum alloy.