Heat treatment processes, due to qualitative requirements for the cast machinery components and restrictions on energy consumption resulting on the one hand from environmental concerns, and on the other hand from a requirements coming from minimization of manufacturing costs, are resulting in searching after a technologies enabling obtainment of satisfactory results, in form of improved mechanical properties mainly, while minimizing (limiting) parameters of successive operations of the heat treatment. Heat treatment of the T6 type presented in this paper consists in operations of heating of investigated alloys to suitably selected temperature (range of this temperature was evaluated on the base of the ATD method), holding at such temperature for a short time, and next rapid cooling in water (20 oC) followed by artificial ageing, could be such technology in term s of above mentioned understanding of this issue. Performed T6 heat treatment with limited parameters of solutioning operation resulted in visible increase in tensile strength Rm of AlSi7Mg, AlSi7Cu3Mg and AlSi9Cu3(Fe) alloys.

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.

Mechanical properties of aluminum-silicon alloys are defined by condition of alloying components in the structure, i.e. plastic metallic matrix created from solid solution  on the basis of Al, as well as hard and brittle precipitations of silicon. Size and distribution of silicon crystals are the main factors having effect on field of practical applications of such alloys. Registration of crystallization processes of the alloys on stage of their preparation is directly connected with practical implementation of crystallization theory to controlling technological processes, enabling obtainment of suitable structure of the material and determining its usage for specific requirements. An attempt to evaluate correlation between values of characteristic points laying on crystallization curves and recorded with use of developed by the author TVDA method (commonly denominated as ATND method) is presented in the paper together with assessment of hardness of tested alloy. Basing on characteristic points from the TVDA method, hardness of EN AC-AlSi9Mg alloy modified with strontium has been described in the paper in a significant way by the first order polynomial.

Mechanical and technological properties of castings made from 3xx.x alloys depend mainly on properly performed process of melting and

casting, structure of a casting and mould, as well as possible heat treatment. Precipitation processes occurring during the heat treatment of

the silumins containing additives of Cu and/or Mg have effect on improvement of mechanical properties of the material, while choice of

parameters of solutioning and ageing treatments belongs to objectives of research work performed by a number of authors. Shortened heat

treatment, which is presented in the paper assures suitable mechanical properties (Rm), and simultaneously doesn’t cause any increase of

production costs of a given component due to long lasting operations of the solutioning and ageing. Results of the research concern effects

of the solutioning and ageing parameters on the Rm tensile strength presented in form of the second degree polynomial and illustrated in

spatial diagrams. Performed shortened heat treatment results in considerable increase of the Rm tensile strength of the 320.0 alloy as early

as after 1 hour of the solutioning and 2 hours of the ageing performed in suitable.

The most important parameters which predetermine mechanical properties of a material in aspects of suitability for castings to machinery components are: tensile strength (Rm), elongation (A5, hardness (HB) and impact strength (KCV). Heat treatment of aluminum alloys is performed to increase mechanical properties of the alloys mainly. The paper comprises a testing work concerning effect of heat treatment process consisting of solution heat treatment and natural ageing on mechanical properties and structure of AlZn10Si7MgCu alloy moulded in metal moulds. Investigated alloy was melted in an electric resistance furnace. Run of crystallization was presented with use of thermal-derivative method (ATD). This method was also implemented to determination of heat treatment temperature ranges of the alloy. Performed investigations have enabled determination of heat treatment parameters’ range, which conditions suitable mechanical properties of the investigated alloy. Further investigations will be connected with determination of optimal parameters of T6 heat treatment of the investigated alloy and their effect on change of structure and mechanical/technological properties of the investigated alloy.

Heat treatment of a casting elements poured from silumins belongs to technological processes aimed mainly at change of their mechanical

properties in solid state, inducing predetermined structural changes, which are based on precipitation processes (structural strengthening of

the material), being a derivative of temperature and duration of solutioning and ageing operations. The subject-matter of this paper is the

issue concerning implementation of a heat treatment process, basing on selection of dispersion hardening parameters to assure

improvement of technological quality in terms of mechanical properties of a clamping element of energy network suspension, poured from

hypoeutectic silumin of the LM25 brand; performed on the basis of experimental research program with use of the ATD method, serving

to determination of temperature range of solutioning and ageing treatments. The heat treatment performed in laboratory conditions on a

component of energy network suspension has enabled increase of the tensile strength Rm and the hardness HB with about 60-70%

comparing to the casting without the heat treatment, when the casting was solutioned at temperature 520 o

C for 1 hour and aged at

temperature 165 o

C during 3 hours.

Very well-known advantages of aluminum alloys, such as low mass, good mechanical properties, corrosion resistance, machining-ability,

high recycling potential and low cost are considered as a driving force for their development, i.e. implementation in new applications as

early as in stage of structural design, as well as in development of new technological solutions. Mechanical and technological properties of

the castings made from the 3xx.x group of alloys depend mainly on correctly performed processes of melting and casting, design of a

mould and cast element, and a possible heat treatment.

The subject-matter of this paper is elaboration of a diagrams and dependencies between parameters of dispersion hardening (temperatures

and times of solutioning and ageing treatments) and mechanical properties obtained after heat treatment of the 356.0 (EN AC AlSi7Mg)

alloy, enabling full control of dispersion hardening process to programming and obtaining a certain technological quality of the alloy in

terms of its mechanical properties after performed heat treatments. Obtained results of the investigations have enabled obtainment of a

dependencies depicting effect of parameters of the solutioning and ageing treatments on the mechanical properties (Rm, A5 and KC impact

strength) of the investigated alloy. Spatial diagrams elaborated on the basis of these dependencies enable us to determine tendencies of

changes of the mechanical properties of the 356.0 alloy in complete analyzed range of temperature and duration of the solutioning and

ageing operations.

Dispersion hardening, as the main heat treatment of silumins having additions of copper and magnesium, results in considerable increase

of tensile strength and hardness, with simultaneous decrease of ductility of the alloy. In the paper is presented an attempt of introduction of

heat treatment operation consisting in homogenizing treatment prior operation of the dispersion hardening, to minimize negative effects of

the T6 heat treatment on plastic properties of hypereutectoidal AlSi17CuNiMg alloy. Tests of the mechanical properties were performed

on a test pieces poured in standardized metal moulds. Parameters of different variants of the heat treatment, i.e. temperature and time of

soaking for individual operations were selected basing on the ATD (Thermal Derivation Analysis) diagram and analysis of literature. The

homogenizing treatment significantly improves ductility of the alloy, resulting in a threefold increase of the elongation and more than

fourfold increase of the impact strength in comparison with initial state of the alloy. Moreover, the hardness and the tensile strength (Rm)

of the alloy decrease considerably. On the other hand, combination of the homogenizing and dispersion hardening enables increase of

elongation with about 40%, and increase of the impact strength with about 25%, comparing with these values after the T6 treatment,

maintaining high hardness and slight increase of the tensile strength, comparing with the alloy after the dispersion hardening

To the main advantages of magnesium alloys belongs their low density, and just because of such property the alloys are used in aviation and rocket structures, and in all other applications, where mass of products have significant importance for conditions of their operation. To additional advantages of the magnesium alloys belongs good corrosion resistance, par with or even surpassing aluminum alloys. Magnesium is the lightest of all the engineering metals, having a density of 1.74 g/cm3 . It is 35% lighter than aluminum (2.7 g/cm3 ) and over four times lighter than steel (7.86 g/cm3 ). The Mg-Li alloys belong to a light-weight metallic structural materials having mass density of 1.35-1.65 g/cm3 , what means they are two times lighter than aluminum alloys. Such value of mass density means that density of these alloys is comparable with density of plastics used as structural materials, and therefore Mg–Li alloys belong to the lightest of all metal alloys. In the present paper are discussed melting and crystallization processes of ultra-light weight MgLi12,5 alloys recorded with use of ATND methods. Investigated magnesium alloy was produced in Krakow Foundry Research Institute on experimental stand to melting and casting of ultra-light weight alloys. Obtained test results in form of recorded curves from ATND methods have enabled determination of characteristic temperatures of phase transitions of the investigated alloy.

Automation of machining operations, being result of mass volume production of components, imposes more restrictive requirements

concerning mechanical properties of starting materials, inclusive of machinability mainly. In stage of preparation of material, the

machinability is influenced by such factors as chemical composition, structure, mechanical properties, plastic working and heat treatment,

as well as a factors present during machining operations, as machining type, cutting parameters, material and geometry of cutting tools,

stiffness of the system: workpiece – machine tool – fixture and cutting tool.

In the paper are presented investigations concerning machinability of the EN AC-AlSi9Cu3(Fe) silumin put to refining, modification and

heat treatment. As the parameter to describe starting condition of the alloy was used its tensile strength Rm. Measurement of the machining

properties of the investigated alloy was performed using a reboring method with measurement of cutting force, cutting torque and cutting

power. It has been determined an effect of the starting condition of the alloy on its machining properties in terms of the cutting power,

being indication of machinability of the investigated alloy. The best machining properties (minimal cutting power - Pc=48,3W) were

obtained for the refined alloy, without heat treatment, for which the tensile strength Rm=250 MPa. The worst machinability (maximal

cutting power Pc=89,0W) was obtained for the alloy after refining, solutioning at temperature 510 o

C for 1,5 hour and aged for 5 hours at

temperature 175 o

C. A further investigations should be connected with selection of optimal parameters of solutioning and ageing

treatments, and with their effect on the starting condition of the alloy in terms of improvement of both mechanical properties of the alloy

and its machining properties, taking into consideration obtained surface roughness.