SEARCH RESULT

In this study, laser surface hardening process was applied to the 8620 steel which is used in the parts, for the machines and automobiles, gear wheels, pins and shaft enamel. Laser power and laser feed rate were determined as laser surface hardening parameters. It has been studied between 1050 and 1400 W as laser power. 4 and 6 mm velocities were preferred as the feed rate. The hardness of the samples was measured under 500 g (HV0,5) load for 15 seconds. Nikon brand optical microscope is used for microstructure studies. According to the hardness results, the hardness of hardness of 8620 steel was obtained with 1400 W laser force and 6 mm feed speed.

International Iron & Steel Symposium
UDCS

Harun ÇUĞ Mehmet Akif Erden İsmet Faruk AYDIN

In this study, Fe-based composites containing 1, 2 and 4% (by weight) SiC were produced by conventional powder metallurgy method. The powders were weighed in the sensitive balance and pressed under pressure of 750 MPa after 1 hour of blending. After pressing, the composite materials were sintered at 1100 °C for 1 hour. With the increasing the amount of SiC, the decrease in density amounts, the increase hardness and porosity values were determined.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Hasan Karabulut

In this study, laser surface hardening process was applied to the low carbon steel which is used in the parts, for the machines and automobiles, gear wheels, pins and shaft enamel. Laser power and laser feed rate were determined as laser surface hardening parameters. It has been studied between 1050 and 1300 W as laser power. 4 and 6 mm velocities were preferred as the feed rate. The hardness of the samples was measured under 500 g (HV0,5) load for 15 seconds. Nikon brand optical microscope is used for microstructure studies. As a result of the hardening, the expected hardness on the surface could not be obtained due to the low carbon content. Due to the effect of the laser, carbon is deposited on certain areas and formed non-uniform regions. As a result, it was found that it was difficult to achieve the desired effect from laser hardening process without carburizing the low carbon steels.

International Iron & Steel Symposium
UDCS

Harun ÇUĞ Mehmet Akif Erden

This work can be located to two parts. In the first part, hydrothermal carbon (HTC) was synthesized from cellulose at 180 ℃ for 20 hours. In the second part, HTCs reinforced iron matrix composites were fabricated via powder metallurgy. For this fabrication process, HTCs and iron powders were mixed by turbula mixer for one hour. Then, obtained mixtures of powders were compacted by press machine at 700 Mpa. After that, green billets were sintered at 1100 ℃ for one hour. Microstructures of samples were characterized by Scanning Electron Microscope (SEM). Density measurement was applied according to Archimedes method. Hardness and compression tests were conducted to determine mechanical properties of samples.

International Iron & Steel Symposium
UDCS

Hamza Simsir Yasin Akgül Mehmet Akif Erden

In this study, a mixture of unalloyed steel material in the desired composition via powder metallurgy method is obtained by adding 0.5% by weight of graphite element in Fe matrix. The powders obtained were mixed by using a 4, 5 and 6 mm ball in the mechanical mixing device and the mixture was mixed with powder and ball ratio 1/10 for 1 hour. Powders obtained after mixing were squeezed at pressures of 700 MPa at 1350⁰C sintering temperature in 1 hour in the molds designed as tensile specimens. The particle size of the produced steels and the distribution of the phases were determined by optical microscope. After microstructure analysis, tensile test was applied to steel samples prepared in tensile specimen dimensions. The elongation, yield-tensile strength of the samples are explained depending on the ball diameter. As a result, steel samples with a ball diameter of 5 mm exhibited the highest yield and tensile strength.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Selim Erman Harun ÇUĞ

In this study, Fe based SiC reinforced composites were produced by powder metallurgy method. Fe-Graphite and SiC powders were weighed with a scale of 0.0001 g and then blended for 1 hour. It was then pressed under pressure of 750 MPa. After the pressing process, the composite materials were sintered at 1100 °C, 1200 °C and 1300 °C for 1 hour in argon atmosphere. With increasing sintering temperatures, an increase in density values and a decrease in porosity were determined. The ideal hardness results for the composites were obtained by sintering at 1100 ° C.

International Iron & Steel Symposium
UDCS

Hasan Karabulut Mehmet Akif Erden

— In this study, Fe based composites containing Al2O3 at 1, 3 and 5% by weight were produced by powder metallurgy method. The powders were weighed in the sensitive balance and pressed under pressure of 750 MPa after 1 hour blending. After pressing, the composite materials were sintered at 1100 °C for 1 hour. With the increase in Al2O3, the density decreased, the hardness and porosity increased.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden

In this study, a mixture of unalloyed steel material in the desired composition via powder metallurgy method is obtained by adding 0.5% by weight of graphite element in Fe matrix. The powders obtained were mixed by using a 5 mm ball in the mechanical mixing device and the mixture was mixed with powder and ball ratio of 1/10 for 1-2 and 3 hours. Powders obtained after mixing were squeezed at pressures of 700 MPa at 1350⁰C sintering temperature in 1 hour in the molds designed as tensile specimens. The particle size of the produced steels and the distribution of the phases were determined by optical microscope. After microstructure analysis, tensile test was applied to steel samples prepared in tensile specimen dimensions. The elongation, yield-tensile strength of the samples are explained depending on the mechanical alloying time. As a result, steel samples for 1 hour exhibited the highest yield and tensile strength.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Selim Erman Harun ÇUĞ

In this study, a mixture of unalloyed steel material in the desired composition via powder metallurgy method is obtained by adding 0.5% by weight of graphite element in Fe matrix. The powders obtained were mixed by using a 5 mm ball in the mechanical mixing device and the mixture was mixed with powder and ball ratio of 1/5, 1/7 and 1/10 for 1 hour. Powders obtained after mixing were squeezed at pressures of 700 MPa at 1350⁰C sintering temperature in 1 hour in the molds designed as tensile specimens. Tensile test was applied to steel samples prepared in tensile specimen dimensions. The elongation, yieldtensile strength of the samples are explained depending on the powder and ball ratio. As a result, steel samples with powder and ball ratio 1/10 for 1 hour exhibited the highest yield and tensile strength.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Selim Erman Harun ÇUĞ

In this study, Fe matrix composites with different amounts of graphene nanoplatelets (0.2-0.5-0.8 wt%) were produced via powder metallurgy. Tribological behaviors of samples were determined with a dry sliding wear test. Results were compared with Fe-Graphite (C) composites. Microstructures of samples were investigated by the optical microscope. Vickers hardness and density measurement were performed for all samples. Also, worn surfaces of samples were observed with a Scanning Electron Microscope (SEM). Results show that all graphene nanoplatelets (GNPs) containing samples showed better wear resistance behavior compared to graphite containing samples. However, the same trend was not observed according to hardness test results. 0.8 wt% graphite-Fe sample has a higher hardness value than 0.8 wt% (GNPs)-Fe sample.

International Iron & Steel Symposium
UDCS

Salih BEKTAS Mehmet Akif Erden Ahmet Nusret Tanrıverdi Yasin Akgül

In this work, the effect of Cr content on the microstructures and tensile behaviors of nonalloyed powder metallurgy (PM) steels were investigated. The samples pressed at 700 MPa and sintered at 1400°C temperature in the sintering argon atmosphere for 1 h were produced. Nonalloyed PM microalloyed steels with different Cr ratio were analyzed in terms of tensile test. The microstructure of the PM steels was characterised by optic microscope. Results indicated that 5 wt. % Cr added PM steel showed the highest values in yield strength (YS) and ultimate tensile strength (UTS)

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Rıfat GÜNDÜZ

In this work, the effect of graphite content on the microstructures and tensile behaviors of Mo added powder metallurgy (PM) steels were investigated. The samples pressed at 700 MPa and sintered at 1400°C temperature in the argon atmosphere for 1 h were produced. Mo added PM microalloyed steels with different graphite ratio were analyzed in terms of microstructure and tensile test. Results indicated that as the amount of the graphite in the PM steels increases, the volume fraction of the pearlite increases gradually. Mo aded PM steel contained 0.6 wt. % graphite showed the highest values in yield strength (YS) and ultimate tensile strength (UTS).

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Hasan Karabulut Süleyman GÜNDÜZ

In this work, the effect of Nb content on the microstructures and tensile behaviors of Nb-V added microalloyed powder metallurgy (PM) steels were investigated. The samples were pressed at 700 MPa and sintered at 1400°C temperature in argon atmosphere for 1 hour. Nb-V added PM microalloyed steels with different niobium ratio were analyzed by tensile test. The microstructure of the PM steels was characterised by optic microscope. Results indicated that 0.075 wt. % Nb added PM steel showed the highest values in yield strength (YS) and ultimate tensile strength (UTS). However, when the amount of Nb content increased from 0.075 to 5 wt.%, yield strength and ultimate tensile strength decreased. Elongation also tends to decrease with increasing Nb content.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Ferhat KAHVECİGİL Özkan KARAOĞLU

In this work, the relatıon sheep between microstructure and mechanical properties of carburizing steel steel produced by powder metallurgy method were investigated. The samples pressed at 700 MPa and sintered at 1400 °C temperature in the sintering argon atmosphere for 1 h were produced. Steels which have carburized and uncarburized were analyzed in terms of tensile and hardness test. The microstructure of the PM steels was characterized by optic microscope. Results indicated that carburizing steel can be produced.

International Iron & Steel Symposium
UDCS

Mehmet Akif Erden Özcan TOPÇU

In this work, the effect of Mo and Ni (3 wt.) on the microstructures and tensile behaviors of powder metallurgy (PM) steels were investigated. Comparing in terms of mechanical properties, C ratios in Mo-Ni PM steels are kept constant and the effects of Mo and Ni are examined. Before the mixing process, the powders were prepared by weighing on a digital precision scale of 0.0001 g precision. The mixing process was conducted without ball using a Turbula T2F mixer for 1 hour. Having mixed homogeneously, the powders were pressed with cold under 700 MPa unidirectionally with a Hidroliksan press of 96 ton pressure capacity according to ASTM (E8M) standards of powder metal material tension test sample. The pressed samples were sintered at 1400 °C for 1 hour in argon atmosphere. Tensile test was made at 0.5 mm/min crosshead speed with Shimadzu tensile device that has 50 KN capacity. The tensile strength and elongation % of the tensile test samples were determined. After sintering, density (%)were measured. Microstructure examinations were carried out with Nikon Epiphot 200 brand optical microscope. Density of the samples was measured with the density measurement tool according to Archimedes principle. It is clear that the mechanical properties of 3 wt. % Mo and Ni added PM steel is better than that of 0 and 3 wt. % Mo added PM steels.

International Symposium on Railway System Engineering
ISERSE

Mehmet Akif Erden

Bu çalışmada toz metalurjisi yöntemiyle Fe matris içerisine % ağırlık olarak 0,4 grafit elementinin katılmasıyla istenilen bileşimde alaşımsız çelik malzeme toz karışım olarak elde edilmiştir. Elde edilen tozlar çekme numunesi şeklinde tasarlanan kalıplarda 700 MPa presleme basıncında sıkıştırılarak 1200⁰C, 1300⁰C ve 1400⁰C’de argon atmosferinde 1saat sinterlenerek çelik malzeme üretimi gerçekleştirilmiştir. Üretilen çeliklerinin tane boyutu ve fazların dağılımı optik mikroskop ile belirlenmiştir. Mikroyapı analizinden sonra çekme numunesi boyutlarında hazırlanan çelik numunelere çekme testi uygulanmıştır. Numunelerin % uzama, akma-çekme dayanımları sinterleme süresine bağlı olarak açıklanmıştır. Sonuç olarak, 1300⁰C’de argon atmosferinde sinterlenen çelik numuneler en yüksek akma ve çekme dayanımı sergilemiştir. In this study, a mixture of unalloyed steel material in the desired composition via powder metallurgy method is obtained by adding 0.4% by weight of graphite element in Fe matrix. The obtained powders were squeezed at pressures of 700 MPa at 1200⁰C, 1300⁰C and 1400⁰C sintering temperature in 1 hour in the molds designed as tensile specimens. The particle size of the produced steels and the distribution of the phases were determined by optical microscope. After microstructure analysis, tensile test was applied to steel samples prepared in tensile specimen dimensions. The elongation, yieldtensile strength of the samples are explained depending on the sintering temperature. As a result, steel samples sintered at 1300 °C in an argon atmosphere exhibited the highest yield and tensile strength.

International Symposium on Railway System Engineering
ISERSE

Mehmet Akif Erden

Bu çalışmada toz metalurjisi yöntemiyle Fe matris içerisine % ağırlık olarak 0,4 grafit elementinin katılmasıyla istenilen bileşimde alaşımsız çelik malzeme toz karışım olarak elde edilmiştir. Elde edilen tozlar çekme numunesi şeklinde tasarlanan kalıplarda 700 MPa presleme basıncında sıkıştırılarak 1300⁰C’de argon atmosferinde 1saat ve 2 saat sinterlenerek çelik malzeme üretimi gerçekleştirilmiştir. Üretilen kompozit çeliklerinin tane boyutu ve fazların dağılımı optik mikroskop ile belirlenmiştir. Mikroyapı analizinden sonra çekme numunesi boyutlarında hazırlanan çelik numunelere çekme testi uygulanmıştır. Numunelerin % uzama, akma-çekme dayanımları sinterleme süresine bağlı olarak açıklanmıştır. Sonuç olarak, 1300⁰C’de argon atmosferinde 2 saat sinterlenen çelik numuneler en yüksek akma ve çekme dayanımı sergilemiştir. In this study, a mixture of unalloyed steel material in the desired composition via powder metallurgy method is obtained by adding 0.4% by weight of graphite element in Fe matrix. The obtained powders were squeezed at pressures of 700 MPa at 1300⁰C sintering temperature in 1 hour and 2 hour in the molds designed as tensile specimens. The particle size of the produced steels and the distribution of the phases were determined by optical microscope. After microstructure analysis, tensile test was applied to steel samples prepared in tensile specimen dimensions. The elongation, yield-tensile strength of the samples are explained depending on the sintering temperature. As a result, steel samples sintered at 1300 °C in 2 hour in an argon atmosphere exhibited the highest yield and tensile strength.

International Symposium on Railway System Engineering
ISERSE

Mehmet Akif Erden