Yazar "Ozlu, Baris" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    The Effect of Mechanical Properties and the Cutting Parameters on Machinability of AISI 5140 Steel Cooled at High Cooling Rates After Hot Forging
    (Gazi Univ, 2019) Ozlu, Baris; Demir, Halil; Turkmen, Mustafa
    In this study, the effect of mechanical properties and cutting parameters (Cp) on the machinability of AISI 5140 steel cooled at high cooling rates after hot forging was investigated. The microstructural examinations and hardness measurements of the as-received AISI 5140 steel and the workpieces cooled in the oil and polymerized water after hot forging were performed. Turning process was conducted by using a coated ceramic tool at five different cutting speeds (Vc) (120, 150, 180, 210, and 240 m/min), four different feed rates (fn) (0.04, 0.08, 0.12, and 0.16 mm/rev), and four different depths of cut (ap) (0.4, 0.6, 0.8, and 1 mm) under dry machining conditions. SEM examinations of the cutting tools were also performed. It was seen from the results that the changing microstructure and hardness values had a significant effect on cutting forces (Fc) and surface roughness (Ra) from the Cp depending on cooling rate. While the highest Fc were reached in the workpiece with the highest hardness cooled in the polymerized water after hot forging, the lowest surface roughness (Ra) was obtained in the same workpiece.
  • Küçük Resim Yok
    Öğe
    Evaluation of the effect of hot forging and cooling conditions on the microstructure, hardness and machinability of medium carbon DIN 41Cr4 steel
    (Gazi Univ, Fac Engineering Architecture, 2023) Ozlu, Baris; Akgun, Mahir; Demir, Halil
    This work DIN 41Cr4 tempered steel of hot forging applied focuses on the investigation of machinability of samples obtained by cooling in sand and air. The machinability evaluation has made in terms of main cutting force (Fc) and surface roughness (Ra). DIN 41Cr4 original material (OM), sand (SC) and air cooling (AC) samples has investigate microstructure and hardness changes. Turning experiments carried out at five different cutting speeds, four different feed rates and depth of cut. As a result, it has seen that the cooling environment of the samples after hot forging has a significant effect on the hardness and microstructure. The lowest main Fc was 131.54 N in the OM, while the highest Fc was 337.49 N in the AC sample in the turning of the samples. Evaluated in terms of Ra, the lowest Ra was obtained as 0.505 mu m in the AC sample, while the highest Ra was obtained as OM 1.793 mu m. It has been observed that the main Fc increases, while the Ra somewhat decreases depending on the increase in hardness and decrease in grain size. In general, SEM examinations, it has been seen that built-up edge (BUE) and breaks occurred in the cutting tools.
  • Küçük Resim Yok
    Öğe
    Multi-objective Optimization of Process Parameters for Surface Quality and Geometric Tolerances of AlSi10Mg Samples Produced by Additive Manufacturing Method Using Taguchi-Based Gray Relational Analysis
    (Springer Heidelberg, 2024) Isik, Ugur; Demir, Halil; Ozlu, Baris
    In this study, it has been focused on examining the effects of production parameters on quality parameters such as surface roughness and geometric tolerances in the production of AlSi10Mg samples by the additive manufacturing method. The experimental design has been prepared according to the Taguchi L27 orthogonal array. As a result, in the production of samples, increasing laser power (P) contributed positively to surface roughness and diameter change, and increasing scanning distance (SD) negatively contributed to circularity change and concentricity. Further, it has been determined that increasing the scanning speed (SS) negatively affects the concentricity change of the produced samples. The optimum production parameters for surface roughness and diameter variation has been determined as A1B1C3. The optimum production parameters for circularity variation and concentricity have been determined as A3B3C1 and A3B1C1, respectively. According to the ANOVA analysis results, the most effective parameters for surface roughness, diameter change, circularity change and concentricity have been 53.22% P, 62.45% SD, 37.23% SS and 40.41% SD, respectively. Furthermore, as a result of the gray relationship analysis (GRA) performed for the output parameters, the optimum production parameter has been determined as A2B1C3.