Hardness and Elastic Modulus of Al-Based Composite Developed from Aluminium Piston Scraps Using Alumina and Snail shell as Reinforcements

This paper presents the relationship between the Young’s modulus and hardness of composites developed from recycled aluminium pistons reinforced with alumina and snailshells. The percentages of alumina and snailshells were kept within the range of 0-30 and 0-10 wt.%, respectively. Experiments were designed using response surface methodology (RSM) to evaluate the influence of the reinforcements on the tensile, hardness and Young’s modulus of the composites. The theoretical hardness was analyzed from the ratio of indentation hardness to indentation modulus while the Young’s modulus was evaluated from the composite equations. The results indicate that an increased fraction of the hybrid reinforcement does not necessarily translate to higher hardness value and Young’s modulus. The sample with the best characteristics has a tensile strength of 172.5 MPa, modulus of resilience of 28.28 GPa and hardness value of 44.9 RHN. The average experimental Young’s modulus of the samples is about 30% of the theoretical value of 86.5GPa while experimental hardness value of 44.90 is about twice that of the theoretical value. The discrepancy between the experimental and theoretical modulus is due to the assumption of a perfect crystal for the former as against polycrystalline crystals. The two samples with the highest modulus of resilience were chosen and further characterized. Scanning Electron Microscope images showed that the fillers in the two samples were well bonded with the aluminium matrix. Keywords - Mechanical Properties, Casting, Aluminum composite, Alumina and Snailshells

Quality Management of Aluminum Pistons with the Use of Quality Control Points

The publication analyses the way of managing and improving the quality of the production process of aluminum pistons for internal combustion engines. The aim of the article is to propose a method of analysis of the effectiveness of individual control methods used in the process of controlling the aluminium piston. Thanks to the location of a control point with the highest share of product non-compliance detection in the production process, it is possible to reduce quality control points by less effective points, which will contribute to lower costs or shorten the time of production processes. In view of the increasing demands on the efficiency of the checkpoints for components in internal combustion engines, the issue is important and topical.

UJI KETAHANAN FATIK ALUMINIUM SCRAP HASIL REMELTING PISTON BEKAS MENGGUNAKAN ALAT UJI FATIK TIPE ROTARY BENDING

Aluminium merupakan salah satu logam non-ferrous yang paling banyak dipergunakan dalam bidang keteknikan karena memiliki sifat yang ringan, tahan terhadap korosi, dan dapat didaur ulang. Daur ulang adalah proses untuk menjadikan suatu bahan bekas menjadikan suatu bahan bekas menjadi suatu yang berguna. Dalam penelitian ini dilakukan daur ulang dengan metode remelting aluminium piston bekas dengan harapan nantinya bahan piston bekas dapat dipergunakan kembali. Tujuan penelitian ini adalah untuk mengetahai nilai kelelahan fatik aluminium hasil remelting piston bekas pada variasi beban yang berbeda. Metode penelitian memvariasikan beban 40%, 50%, dan 60% dari Yield Strength untuk menghasilkan nilai kelelahan. Nilai uji fatik dari pembebanan 40% Yield Strength diberi beban 1,2 kg mendapatkan nilai siklus putaran 171.026 dan waktu patah 01:34:01 detik. Pada pembebanan 50% Yield Strength diberi beban 1,5 kg mendapatkan nilai siklus putaran 56.796 dengan waktu patah 00:37:52 detik. Pada pembebanan 60% Yield Strength diberi beban 1,8 kg mendapatkan nilai siklus putaran 24.384 dan waktu patah 00:16:15 detik. Semakin besar beban yang diberikan semakin kecil siklus dan waktu yang dihasilkan, sebaliknya semakin kecil beban yang diberikan semakin besar siklus dan waktu yang dihasilkan.Kata kunci : Aluminium scrap, Piston bekas, Remelting, Uji fatik, Rotary bending.