Stress relief of mechanically roughened cylinder bores for reduced cracking tendency
AssigneeGM Global Technology Operations LLC
InventorsYucong Wang, Martin S. Kramer
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Abstract
A method of treating the surface of an aluminum-based engine block cylinder bore that has been mechanically roughened. In one form, this method includes using vibratory stress relief, elevated temperature stress relief or cryogenic stress relief so that residual stresses imparted to the surface by the roughening process are reduced. In this way, a protective coating that is also applied to the bore surface will exhibit better adhesion and lower incidence of stress-induced or fatigue-induced cracking.
Claims20
A method of treating a cylinder bore that is formed in an aluminum-based engine block, said method comprising:
- activating an exposed surface of said bore with mechanical roughening;
- and
- reducing residual stress present in said activated surface through at least one of vibration stress relief, elevated temperature stress relief and cryogenic stress relief.
A method of forming a cylinder bore in an aluminum-based engine block, said method comprising:
- casting said block to define at least one cylinder bore therein;
- activating an exposed surface of said bore with mechanical roughening;
- and
- reducing residual stress present in said activated surface, said reducing selected from the group consisting of vibration stress relief, elevated temperature stress relief and cryogenic stress relief.
An aluminum-based engine block defining at least one cylinder bore therein, said at least one bore comprising an exposed surface formed with mechanically-roughened features, said exposed surface comprising a treatment thereto in order to define a stress level therein that is reduced relative to if no said treatment were applied.
Dependencies are inferred from the claim text.