SEARCH RESULT

Today, parallel to the rapid development of the industry, mechanical and metallurgical properties of the steel profiles that used as structural elements for constructions need to be improved. The constructions where steel profiles are used scaling up over time, require higher strength values for the materials or larger cross-sectional areas. Larger cross-sectional area has significant disadvantages in terms of product cost due to the weight increase, and the addition of strength-enhancing microalloys has significant disadvantages in terms of raw material cost. In this study, low-carbon and non-microalloyed base quality steel profiles that neither the hard nor the very soft material structure of undesirable were subjected to quenching of the profile surface to a certain depth with the quenching method, and then tempered the cooled surface by the region which was hot in the profile center. The changes in mechanical and metallurgical properties of the materials tested as a result of the process application designed according to the steel profile quality and cross-section. According to the results obtained, it was determined that the mechanical properties of the material increased and this increment was observed by the change in the material microstructure which was caused by the applied process. As a result of the study, it has been determined that more economical solutions can be revealed with the quenching process instead of using microalloying by using rare elements in a working environment where competition is gradually increasing.

International Iron & Steel Symposium
UDCS

Mehmet Akkaş Ezgi SEVGİ Burak ÖNDER Aytaç BAŞSÜLLÜ Osman Çulha

Hybrid composites are materials that have a combination of two or more reinforcements. These materials have extensive engineering applications that have a low strength/density ratio, low cost and ease of manufacturing. Hybrid composites provide a combination of properties such as tensile modulus, compressive strength and impact resistance, which cannot be realized in composite materials. The surface properties of the materials must be improved against corrosion and wear. It is therefore essential and important that the coating layer has both wear and corrosion resistant phases. In this study, the surface of AISI 316L stainless steel is coated with metal powder having different composition by tungsten inert gas (TIG) welding surface coating method. Ti, B4C and SiC metal powders of different ratios were used as coating powder. The corrosion properties of coated samples were characterized by potentiostatic polarization test. Corrosion test results showed that corrosion properties vary depending on the coating components.

International Iron & Steel Symposium
UDCS

Serkan Islak Mehmet Akkaş Cihan Özorak Aytekin Ulutaş

Copper, which is known to have very good electrical and thermal conductivity, has poor mechanical properties. In order to overcome this negativity, the production of coppermatrix composites is becoming increasingly popular. In this study, copper (Cu) matrix ferrochromium (FeCr) and ferroboron (FeB) reinforced composites were produced. Cold pressing and sintering process were preferred as production methods. Microstructure and phase composition of the composites were examined by using scanning electron microscope (SEM). Hardness properties were carried out microhardness device. Also, Densities of composites were studied. SEM images showed that FeCr and FeB reinforcements were partially homogeneously dispersed in the Cu matrix. In the presence of FeCr and FeB in the Cu matrix, the hardness of the Cu matrix was considerably increased.

International Iron & Steel Symposium
UDCS

Mehmet Akkaş Serkan Islak Uğur Çalıgülü Mustafa Boz

In this study, the effects of different gas pressures on the shape and size of Al-12Si alloy powder produced by gas atomization method are investigated experimentally. Experiments were carried out at the Gas Atomization Unit, which was redesigned at Karabuk University Faculty of Technology Department of Manufacturing Engineering. Experiments were carried out at a stable temperature of 770 °C, at a nozzle diameter of 2 mm and by applying 6 different gas pressures (5-10-15-2030-35 bar). Argon gas was used to atomize the melt. In order to determine the size and shape of Al12Si powders produced, scanning electron microscope (SEM) images and powder size analysis were performed by screen analysis method. As a result of the analysis, it was determined that the increase of the gas pressure caused the powder size to decrease and the powder shape to change from the ligament and the dripping structure to the spheroidal. It has been observed that the thinnest powders produced are in the gas pressure of 35 bar and the usually of the powders is complex.

International Iron & Steel Symposium
UDCS

Mehmet Akkaş Tayfun Çetin Atakan Oğuz Ocak Kamal Mohamed Em Akra Mustafa Boz

In this study, which have been made the design, manufacture and product production of the gas atomization unit. The Gas Atomization Unit consists of seven basic sections. These sections can be identified as; Melting furnace, Atomization tower, Nozzle, Powder collecting division, Cyclones and Gas pressure ramp and control panel. The melting furnace is designed to be capable of operating at temperatures up to approximately 1200 ℃. With the aim of prevent the oxidation of molten metal and produced powder, from the sides the of the melting furnace and from tower Argon gas is continuously being sprayed. The melting process is carried out in stainless steel melting pot according to the chemical composition of the material. Al12Si, AZ91, AM60 and AZ31 of the alloys powders were produced first with the gas atomization unit manufactured and designed. It was ascertained that the powders produced were between 0,1 microns and 750 micron and size of the 90 percent of the produced powders were below 100 microns. Experimental studies were carried out using different temperatures, different nozzle and different gas pressures. Argon gas was used to atomize the melt and frame a protective gas atmosphere. SEM-EDX analyzes were used to determine the phases of the internals of the produced powders and the percentage of these phases, and a laser measurement device was used for powder size analysis to determine the shape of powders. Microhardness measurements were also made to determine the hardness of the powders. Besides it was observed that size of powders was decreased depending on the increase of the gas pressure and changed their shapes from ligament to spheroidal. The fracture surface prior to sintering, where the amount of porosity in the specimens decreased and the volumes of the existing pores decreased with the increase of the pressing pressure, were determined from the SEM images. It has been determined that at low sintering temperatures, fracture occurs between intergranular cracks, while ductile fracture occurs as the sintering temperature increases.

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

Mustafa Boz Mehmet Akkaş

In this study, which have been made the design, manufacture and product production of the gas atomization unit. The Gas Atomization Unit consists of seven basic sections. These sections can be identified as; Melting furnace, Atomization tower, Nozzle, Powder collecting division, Cyclones and Gas pressure ramp and control panel. The melting furnace is designed to be capable of operating at temperatures up to approximately 1200 ℃. With the aim of prevent the oxidation of molten metal and produced powder, from the sides the of the melting furnace and from tower Argon gas is continuously being sprayed. The melting process is carried out in stainless steel melting pot according to the chemical composition of the material. Al12Si, AZ91, AM60 and AZ31 of the alloys powders were produced first with the gas atomization unit manufactured and designed. It was ascertained that the powders produced were between 0,1 microns and 750 micron and size of the 90 percent of the produced powders were below 100 microns. Experimental studies were carried out using different temperatures, different nozzle and different gas pressures. Argon gas was used to atomize the melt and frame a protective gas atmosphere. SEM-EDX analyzes were used to determine the phases of the internals of the produced powders and the percentage of these phases, and a laser measurement device was used for powder size analysis to determine the shape of powders. Microhardness measurements were also made to determine the hardness of the powders. Besides it was observed that size of powders was decreased depending on the increase of the gas pressure and changed their shapes from ligament to spheroidal. The fracture surface prior to sintering, where the amount of porosity in the specimens decreased and the volumes of the existing pores decreased with the increase of the pressing pressure, were determined from the SEM images. It has been determined that at low sintering temperatures, fracture occurs between intergranular cracks, while ductile fracture occurs as the sintering temperature increases.

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

Mustafa Boz Mehmet Akkaş