Improvement of Al-Si alloys properties in scope of classic method is connected with change of Si precipitations morphology through:

using modification of the alloy, maintaining suitable temperature of overheating and pouring process, as well as perfection of heat

treatment methods. Growing requirements of the market make it necessary to search after such procedures, which would quickly deliver

positive results with simultaneous consideration of economic aspects. Presented in the paper shortened heat treatment with soaking of the

alloy at temperature near temperature of solidus could be assumed as the method in the above mentioned understanding of the problem.

Such treatment consists in soaking of the alloy to temperature of solutioning, keeping in such temperature, and next, quick quenching in

water (20 0

C) followed by artificial ageing. Temperature ranges of solutioning and ageing treatments implemented in the adopted testing

plan were based on analysis of recorded curves from the ATD method. Obtained results relate to dependencies and spatial diagrams

describing effect of parameters of the solutioning and ageing treatments on HB hardness of the investigated alloy and change of its

microstructure. Performed shortened heat treatment results in precipitation hardening of the investigated 320.0 alloy, what according to

expectations produces increased hardness of the material.