SEARCH RESULT

AISI 52100 steel is considerably attracted in making bearings and shafts due to its greater strength and better corrosion immunity. However, high power consumption is encountered in machining operations due to their hard machinability. The consumption should be eliminated for cleaner production in terms of sustainable machining. Therefore, this study aims modelling of cutting forces in hard turning of AISI 52100 steel based on finite element method. The cutting parameters are chosen as cutting speed and depth of cut with three levels and constant feed rate. The average of 6.6% difference is achieved between experimental and simulated feed forces while 7.5% difference for main cutting forces. The finite element modelling of cutting forces is quite compatible with the experimental results and it can be performed by high accuracy without excessive machining experiments of difficult-to-cut materials.

International Iron & Steel Symposium
UDCS

Mehmet Erdi KORKMAZ

Hard turning is an alternative machining method instead of cylindrical grinding. In this method, more efficient results can be obtained for surface integrity (surface roughness, hardness, residual stress, etc.) of the machined parts when the cutting conditions are optimized. This study includes the optimization of cutting parameters for the minimum surface roughness (Ra) and the development of a mathematical model for estimation of Ra in turning of hardened X40CrMoV5-1 tool steel with ceramic cutting tools. In this context, hard turning tests were made at three different levels using the cutting speed (V), cutting depth (a) and feed rate (f). According to the Taguchi methodology, the optimum cutting parameters were determined as the a2V3f1 test sequence. According to the results of the analysis of interactive variance, the most important parameter was determined as the feed rate.

International Iron & Steel Symposium
UDCS

Mehmet Erdi KORKMAZ Mustafa GÜNAY

The residual stresses induced by any machining process affects fatigue life, corrosion crack resistance and part distortion. Therefore, residual stresses should be predicted better and the cutting parameters should be arranged for minimum value. This paper presents a 2D finite element analysis (FEA) on residual stresses during hard turning of AISI 4140 steel with HSS tools. The cutting parameters are chosen as feed rate and cutting speed with three levels and constant depth of cut. In simulation after the cutting process is finished, both the chip and tool are removed and the workpiece can thermo-mechanically relax. The average of three extraction points on eight different depths of machined surface for residual stresses is calculated for better results. FEA results showed that both tangential and axial residual stresses act as tensile in the depths near the surface until about 75 µm while they act as compressive stress after the depth of 75 µm until about 300 µm. Also, increasing cutting speed has decreasing effect on tensile residual stresses while increasing effect on compressive residual stresses.

International Iron & Steel Symposium
UDCS

Mehmet Erdi KORKMAZ Nafiz YAŞAR Mustafa GÜNAY

Machining parameters for manufacturing methods can be optimized based on the finite element method using numerical simulation software. In this study, the simulation of the hot rolling process was performed for plain round bar producing. Rolling simulations were done in DEFORM-3D software and the hot rolling process was analyzed with three different rolling temperatures and rotation speed of rolls. In the results of numerical analysis, diameter and circularity tolerances have been measured for the product. The outputs of the finite element simulation were evaluated to determine the effects of rolling parameters on size quality of round bar product. The analysis of variance (ANOVA) with %95 confidence level was performed in order to determine the effect level of rolling parameters. It was determined that the rounded product geometry is out of diameter and circularity tolerances by increasing the rolling temperature and the rotational speed.

International Iron & Steel Symposium
UDCS

Emre EROL Mehmet Erdi KORKMAZ Mustafa GÜNAY

Teknoloji ve endüstrinin hızla gelişmesi ile yüksek mukavemetli, hafif ve mükemmel aşınma direncine sahip yapısal malzemelere olan talep sürekli artmaktadır [1,2]. Bu çalışmanın amacı, Al2014 alüminyum alaşımının kaplamasız sementit karbür takım ile delinmesi sonucunda itme kuvvetinin deneysel ve simülasyon sonuçlarını kıyaslamaktır. Bu sayede deneyler sonucunda elde edilecek verilen düşük sapmalar ile simülasyonla da elde edilebileceğini göstermektir. Deneyler ve delme simülasyonlarında ilerleme miktarı ve kesme hızının üç farklı seviyeleri kullanılmıştır. İşleme simülasyonları için yaygın olarak kullanılan [3] Johnson-Cook malzeme modeli Eşitlik 1'de verilmektedir. Malzeme modeli ağırlıklı olarak yüksek gerilme oranı metallerinde deformasyon davranışı için uygundur. Genellikle plastik deformasyon süreçlerinin adyabatik geçici dinamik analizinde kullanılmaktadır. Bu modele göre sertleşme, akma gerilmesinin σ0 olarak kabul edildiği belirli bir izotropik sertleşme türüdür [4]:

International Symposium on Light Alloys and Composite Materials
UHAKS

Mehmet Erdi KORKMAZ Ramazan Çakıroğlu Nafiz YAŞAR Ramazan Özmen Mustafa GÜNAY

In this study, the effects of raster angle on the behavior under the static load of PA12 base materials which were manufactured by Multi Jet Fusion Technology (MJF) in 3D printer, was investigated. For this purpose, standard tensile and three-point bending test samples were produced by 3D printer at a constant deposit thickness (80 µm), constant infill rate (%100) and different printing orientations (0, o 45 and 90 ). Tensile and three-point bending tests were applied for the samples and the findings was evaluated. Consequently, it was determined that the tensile and bending strength of PA12 base sample o has the highest value in 90-90-90 printing orientation.

International Congress on 3D Printing (Additive Manufacturing) Technologies and Digital Industry
3D-PTC2019

Mehmet Erdi KORKMAZ Mustafa GÜNAY

Brass alloys are characterized by excellent workability, high thermal and electric conductivity, corrosion resistance as well as exceptional antibacterial properties and are therefore widely used in various industries, such as electric and electronics, automotive and sanitary industry. However, power consumption should be eliminated for cleaner production in terms of sustainable machining. Therefore, this study aims modelling of cutting forces in hard turning of C23000 brass based on finite element method. The cutting parameters are chosen as cutting speed, depth of cut and feed rate with three levels. The average of 4.66% difference is achieved between experimental and simulated feed forces while 4.39% difference for main cutting forces. The finite element modelling of cutting forces is quite compatible with the experimental results and it can be performed by high accuracy without excessive machining experiments of high machinability materials.

International Data Science & Engineering Symposium
IDSES

Mehmet Erdi KORKMAZ

The improvements which need in railway vehicles made neccessary also brake systems developing. The main factors affecting the performance and functioning of the brake system are brake force, mass and speed of the train, stopping distance and road curvature. With the operating speed exceeding 120 km/h, very different braking systems and equipment have been developed. In this work, the brake systems such as air brakes, dynamic brakes, parking brakes, vacuum brakes, electro-pneumatic brakes have been considered. Especially, evaluations have been made on brake disc-pad systems, which represent the most important components in terms of safe navigation for high-speed trains operating at speeds of 200 km/h and above. For this purpose, experimental and numerical analysis studies on braking system interactions based on brake disk-pad geometry and material properties were investigated. As a result of this study, important information will be gained on the basis of the detailed analysis of the scientific and applied researches which will contribute to the productivity to the institutions and organizations that are in the design and manufacturing activities on the braking systems of our country railway vehicles.

International Symposium on Railway System Engineering
ISERSE

Erhan Selçuk Mehmet Erdi KORKMAZ Mustafa GÜNAY