scholarly journals Effects of T6 heat treatment on the impact strength of AC4C and AC2B aluminum alloy castings solidified for a long times.

1987 ◽  
Vol 37 (7) ◽  
pp. 478-482 ◽  
Author(s):  
Shoji HOTTA ◽  
Katsushi SARUKI ◽  
Motoyuki NAKAMURA
1989 ◽  
Vol 39 (6) ◽  
pp. 451-456
Author(s):  
Yoshihiro SHIMIZU ◽  
Yoji AWANO ◽  
Shohji HOTTA ◽  
Motoyuki NAKAMURA

2017 ◽  
Vol 17 (3) ◽  
pp. 55-58
Author(s):  
A. Jarco

Abstract The paper presents research on the effects of soft annealing parameters on a change of the impact strength KC and Brinell hardness (HB) of the EN AC-AlSi11 alloy. The research has been performed according to the trivalent testing plan for two input parameters – temperature in the range between 280°C and 370°C and time in the range between 2 and 8 hours. The application of such heat treatment improves the plasticity of the investigated alloy. The improvement of the impact strength KC by 71% and the decrease of the hardness HB by 20% was achieved for the soft annealing treatment conducted at a temperature 370°C for 8 hours, compared to the alloy without the heat treatment. A change of the form of eutectic silicon precipitations which underwent refinement, coagulation and partial rounding, had a direct effect on the hardness HB and impact strength KC. The results obtained were used to prepare space plots enabling the temperature and time for soft annealing treatment to be selected with reference to the obtained impact strength KC and hardness HB of the alloy with the heat treatment.


2020 ◽  
Vol 991 ◽  
pp. 86-93
Author(s):  
Priyo Tri Iswanto ◽  
Akhyar Hasan ◽  
Aditya Janata ◽  
Luthfi Muhammad Mauludin ◽  
Hizba Muhammad Sadida

Fatigue behavior of A356 aluminum alloy for motorcycle rim was experimentally investigated based on T6 heat treatment and artificial aging. The high speed of 1,100 rpm from centrifugal casting was used in this study. The pouring temperature at 750 °C was employed and the preheated temperature at 250 °C was applied on the mold. The solution heat treatment of the sample was conducted for 4 hours at 540 o C before it immersed into the water for rapid cooling at room temperature. This step followed by natural aging treatment at 30 °C and artificial aging treatment at 150 °C, 175 °C, and 200 °C for 2 hours, respectively. It is found that increasing centrifugal casting speed into 1,100 rpm combined with heat treatment and artificial aging temperature can significantly increase not only its mechanical properties but also the fatigue life of motorcycle wheel made of A356 aluminum alloy. This experiment proved that the lowest fatigue crack growth rate obtained with this method was at temperature of 175°C.


Author(s):  
P. Kordas

Purpose: Assessment of the possibilities of shaping the structure and improvement of mechanical properties of casting from AlMg10 alloy through a selection of casting technology and precipitation hardening. Design/methodology/approach: the work evaluated the impact of casting and heat treatment technology on the mechanical properties and structure of AlMg10 alloy castings. The tests were performed on 200 mm × 100 mm × 25 mm plate castings produced by gravity casting methods for sand and metal moulds and by a liquid state press moulding technology. Castings made with these technologies solidify in substantially different heat- evaporation conditions and exhibit varying degrees of primary structure fragmentation. Metallographic and strength tests were performed on raw castings and after heat treatment. Findings: The changes in the morphology and size of primary crystals and the dispersion of the reinforcing phase according to the casting solidification rate and the precipitation hardening treatment were analyzed. Solidifying castings in the form of sand show a globular structure, whereas in die and press castings, a typically dendritic structure occurs, with the dendritic crystals in pressed castings being much smaller in size than the die castings. In castings which were not heat-treated, the reinforcing phase of Al3Mg2 occurs in interdendritic spaces, and its dispersion increases with the rate of cooling. After supersaturation and ageing treatments, the phase α has a grain structure in all samples. The largest dispersion of reinforcing molecules is characterized by press castings. In a raw state, the highest mechanical properties are shown by castings made in the form of sand and the method of pressing in a liquid state. Heat treatment of AlMg10 alloy castings significantly influences the increase of mechanical indexes in all castings investigated. The highest features of Rm are approx. 330 MPa and A5 above 10% is obtained in castings made by the press method. Research limitations/implications: Particular attention should be paid to the avoidance of the effects of slag inclusion, shrinkage and magnesium oxidation during casting of AlMg10 alloys. In die castings of a plate type, due to own stresses, a significant decrease in mechanical properties occurs. Practical implications: The most advantageous mechanical properties of AlMg10 alloy castings are obtained by using liquid-state pressing technology. In addition, this technology makes it possible to produce thin-walled castings of high dimensional accuracy, high air- tightness, fine grain structure, lack of surface defects and low roughness. Originality/value: The paper presents the possibility of improving the mechanical properties of AlMg10 castings by applying heat treatment. It has been proven that the casting method has a significant effect on the mechanical properties of the castings.


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