The effects of degassing, grain refinement & Sr-addition on melt quality-hot tear sensitivity relationships in cast A380 aluminum alloy

ULUDAĞ, Muhammet | ÇETİN, Remzi | DIŞPINAR, Derya | TİRYAKİOĞLU, Murat

Hot tearing tendency of A380 with various element additions (Sr, Sr+Ti, Ti, B and B+Sr) was investigated. Constrained rod casting (CRC) hot tearing test method was used to characterize the hot tearing sensitivity. Reduced pressure test (RPT) samples were produced from each condition and all trials were repeated three times. Number density of pores on the cross section of RPT samples was calculated via digital image processing and statistical analysis was carried out. Microstructure analysis was carried out to observe the effect of alloying elements. Hot torn cross sections were subjected to SE ...Daha fazlası

Effect of Sr and Ti Addition on the Corrosion Behavior of Al-7Si-0.3Mg Alloy

ÇETİN, Remzi | ULUDAĞ, Muhammet | KOÇABAŞ, Mustafa | DIŞPINAR, Derya | CANSEVER, Nurhan

In the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approx ...Daha fazlası

Characterization of the Effect of Melt Treatments on Melt Quality in Al-7wt %Si-Mg Alloys

ÇETİN, Remzi | ULUDAĞ, Muhammet | DIŞPINAR, Derya | TİRYAKİOĞLU, Murat

The effects of degassing, holding time and melt additions (Sr, Sr + Ti, Ti, B and B + Sr) on the quality of A356 melts were examined. A total of 120 reduced pressure test samples were collected. Pores in these samples were analyzed via digital image processing to determine the number density of pores as well as the statistical distribution of their sizes. Results showed that in all cases, degassing with argon reduced the number of defects regardless of the additions made to the melts. Moreover, all additions were found to degrade melt quality. The lowest number density of pores in all melts wa ...Daha fazlası

Change in Porosity of A356 by Holding Time and Its Effect on Mechanical Properties

ULUDAĞ, Muhammet | ÇETİN, Remzi | GEMİ, Lokman | DIŞPINAR, Derya

In most of the practical casting operations, it is important to be able to cast large number of part with one single melt. Therefore, when quantity of the charge and melting crucible is increased, during casting process, the liquid is led to settle for a long period of time. In this work, 10 kg charge of A356 was melted at 750 °C and held for 240 min. A sand mold with different thickness was cast at 30, 60, 120, and 240 min of holding time of the liquid, before and after degassing conditions. Melt quality was measured by reduced pressure test, and pore size and number were measured at each cas ...Daha fazlası

Effect of Degassing and Grain Refinement on Hot Tearing Tendency in Al8Si3Cu Alloy

ULUDAĞ, Muhammet | ÇETİN, Remzi | DIŞPINAR, Derya | TİRYAKİOĞLU, Murat

The effect of melt quality on hot tearing susceptibility of Al8Si3Cu alloy was examined under six different conditions, by using a traditional T-shaped mold. Grain refinement was carried out by two different modifiers: AlTi5B1 and Al3B. For each test, samples were cast before and after degassing of melt. Therefore, a new hot tearing tendency index was developed by both bifilm calculations and porosity that occurred in the middle of T-zone of casting parts. Results indicated that hot tearing of cast aluminum alloys was a complex phenomenon, and bifilms play a major role, especially by compensat ...Daha fazlası

On the Interpretation of Melt Quality Assessment of A356 Aluminum Alloy by the Reduced Pressure Test: The Bifilm Index and Its Physical Meaning

ULUDAĞ, Muhammet | ÇETİN,Remzi | DIŞPINAR, Derya | TİRYAKİOĞLU, Murat

The oxide layer on liquid aluminum serves as a protective property to prevent the alloy from further oxidation. However, it has the potential to be a source of porosity when entrained into the bulk of the liquid. For this reason, oxides entrained into aluminum castings have been shown to degrade casting quality. In the current study, the effectiveness of the reduced pressure test in assessing the quality of A356 alloy melts has been investigated under various conditions obtained by changing six different melt parameters. Several metrics, including average pore size, number density of pores, bi ...Daha fazlası

Freezing Range, Melt Quality, and Hot Tearing in Al-Si Alloys

ULUDAĞ, Muhammet | ÇETİN, Remzi | DIŞPINAR, Derya

In this study, three different aluminum-silicon alloys (A356, A413, and A380) that have different solidification morphology and solidification ranges were examined with an aim to evaluate the hot tearing susceptibility. T-shape mold and Constrained Rod Casting (CRC) mold were used for the characterization. Reduced Pressure Test (RPT) was used to quantify the casting quality by measuring bifilm index. It was found that bifilm index and solidification range have an important role on the hot tearing formation. As it is known, bifilms can cause porosity and in this case, it was shown that porosity ...Daha fazlası

Investigation of the efficiency of grain refiners on the hot tearing in Al8Si3Cu alloy

ULUDAĞ, Muhammet | ÇETİN, Remzi | DIŞPINAR, Derya