The article discusses the weldment to casting conversion process of rocker arm designed for operation in a special purpose vehicle to

obtain a consistency of objective functions, which assume the reduced weight of component, the reduced maximum effort of material

under the impact of service loads achieved through topology modification for optimum strength distribution in the sensitive areas, and the

development of rocker arm manufacturing technology. As a result of conducted studies, the unit weight of the item was reduced by 25%,

and the stress limit values were reduced to a level guaranteeing safe application.

The article presents the analysis of properties of the high-strength AlZnMgCu (abbr AlZn) aluminium alloy and estimates possibilities of

its application for responsible structures with reduced weight as an alternative to iron alloy castings. The aim of the conducted studies was

to develop and select the best heat treatment regime for a 7xx casting alloy based on high-strength materials for plastic working from the

7xxx series. For analysis, wrought AlZnMgCu alloy (7075) was selected. Its potential of the estimated as-cast mechanical properties

indicates a broad spectrum of possible applications for automotive parts and in the armaments industry. The resulting tensile and fatigue

properties support the thesis adopted, while the design works further confirm these assumptions.