In the present study, microstructure and porosity of AlSi7Mg0.3 cast alloy including various amounts (0.123; 0.454 and 0.655 wt. %) of iron were investigated. The alloys were produced as secondary (scrap-based -recycled IntroductionAutomotive -chassis, bodies, engine blocks, radiators, hubcaps, and etc. driven by consumer needs and increasingly tight regulations, the automobile industry has made ample recourse to aluminium. A European car today contains on average 100 kg of aluminium, taking advantage of multiple properties of the materials: lightness (a 100 kg loss of weight reduces fuel consumption by 0.6 litres/100 km and greenhouse gases by 20 %), resistance (improved road-handling, absorption of kinetic energy, shorter braking distance) and recycling (95 % of the aluminium contained in autos is collected and recycled, and represents over 50 % of the vehicle's total end-of-life value). Aluminium coming from recycling can allow 95 % energy savings and 85 % less CO 2 emissions compared to primary aluminium production. Recycling -aluminium can be recycled indefinitely without losing any of its intrinsic qualities. This is a considerable advantage in modern metallurgical industry. For the past 20 years the proportion of metal consumed that is recycled has grown steadily and today stands at something like 30 % of primary metal production (European Aluminium Association; Schlesinger, 2014;Hurtalová et al., 2013).The Fig. 1 shows the fraction of world aluminium production from primary and secondary (recycled) sources. About one-third of the aluminium produced in the world is now obtained from secondary sources and in some countries the percentage is much higher. The process used for recycling aluminium scrap is very much different from those used to produce primary metal but in many ways follow the same general sequence. This sequence begins with mining ore, followed by mineral processing and thermal pre-treatment and then a melting step. The metal is then refined, cast into ingots and sent to customers. Aluminium alloys recyclers also face similar challenges to the producers of primary aluminium; there is need to produce a consistent alloy with the required chemistry, reduce the amount of waste generated, minimize energy usage and manufacture the highest-quality product at the lowest possible cost from raw materials of uncertain chemistry and condition (Mc Millan et al., 2012;Schlesinger, 2014).Commercial Al-alloys always contain Fe, often as undesirable impurity and occasionally as a useful minor alloying

It is well known that shot peening is able to increase the fatigue strength and endurance of metal parts, especially with a steep stress gradient due to a notch. This positive effect is mainly put into relation with the ability of this treatment to induce a compressive residual stress state in the surface layer of material and to cause surface work hardening [1]. In this paper shot peening is applied on the 40NiCrMo7 low alloy steel and subsequently the surface was re-peened with glass beads to decrease the final surface roughness. Roughness, hardness and residual stress analysis were used for characterizing the strongly deformed surface layer. Low frequency fatigue tests were carried out to evaluate the effect of the applied treatment on fatigue life in the high cycle region. Results show fatigue strength increase in the high cycle region after the shot peening surface treatment

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This work deals with the fatigue resistance of welded joints manufactured from EN S355 J2 structural steel and the possibility of improving fatigue characteristics by the severe shot peening (SSP) surface treatment. Fatigue testing was carried out by the rotating bending test on specimens manufactured from the base material (BM), welded material and welded material treated by SSP. Results have shown big scatter in obtained results from as-welded material and overall reduction of fatigue endurance when compared to the BM. SSP applied on the welded joints has reduced the scatter of experimental data and increased the fatigue strength. Obtained results of fatigue tests are compared, discussed and supported by correlation with results of additional experiments, e.g. metallographic analyses, microhardness tests, residual stresses measurements and surface roughness measurement.

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