Process for the heat treatment of cylinder heads made of an aluminium-based alloy, and cylinder heads having improved fatigue resistance properties

摘要

The invention relates, according to a first aspect, to a process for the heat treatment of a cylinder head-type casting made from an aluminum alloy, in particular an alloy of aluminum, of silicon and of magnesium, and where appropriate of copper, comprising the steps of: —solution annealing (L) of the part for a time between three and ten hours; —quenching (S) of the part in air or in a fluidized bed; —tempering (H) of the part at the peak of resistance, or in the vicinity of the peak of resistance to attain a level of resistance of the part at least equal to 85% of the maximum level of resistance at the tempering temperature in question. According to a second aspect, the invention relates to the castings obtained at the end of the process according to the invention, and which have an improved fatigue resistance.

主权项

1. A method for heat treatment of an aluminum alloy casting part comprising:
solution annealing the casting part for a duration ranging from three to ten hours; quenching the solution annealed casting part, wherein the solution annealed casting part is cooled during quenching from 495° C. to 200° C. in a duration ranging from 3 minutes 30 seconds to less than 7 minutes 30 seconds; and tempering the quenched casting part at a tempering temperature to attain a resistance level of the part at least equal to 85% of a maximum resistance level at the tempering temperature.