Salim Aslanlar

The Effect Of Nugget Sizes On Mechanical Properties In Resistance Spot Welding Of SPA-C Atmospheric Corrosion Resistant Steel Sheets Used In Rail Vehicles*

Abstract This publication presents an experimental study on the resistance spot welding of SPA-C steel sheets used in side wall and roof application of rail vehicles. SPA-C atmospheric corrosion resistant steel sheets with a thickness of 2.3 mm were joined by using resistance spot welding as lap joint. A timer and current controlled resistance spot welding machine with 120 kVA capacity and a pneumatic application mechanism with a single lever were used to join the specimens. Welding periods were chosen as 5, 10, 15, 20, 25 and 30 cycles (1 cycle = 0.02 s) and also welding currents were increased from 6 kA up to 14 kA by rising in steps of 0.5 kA. The electrode force was kept constant at 6 kN. The welding joints obtained were exposed to tensile peel and tensile shear tests and their nugget sizes were calculated by results of optical microscopy measurements. The effect of nugget sizes on tensile peel strength and tensile shear strength was researched by using related diagrams and the optimum welding currents and times were advised.

An investigation of the factors affecting the design of drum dryers

This work is concerned with the investigation of the factors affecting the design of drum dryers. In the experimental procedure, AISI 4140 was used as a drum material, while HSS was used for a scraping knife. In order to increase the hardness and wear resistance, the drum was coated with the harder chromium, and then it was ground for the improvement of the surface quality. The micro-hardness of the drum was increased more than 10 times of the original drum; as a result better wear resistance was obtained. In addition, electrical measurements were done via a digital ohmmeter to calculate the real contact area between the drum and the scraping knife and the resistance was decreased with the increment of load. Finally, the contact between the couple (drum and knife) was increased with the increment of temperature.

Investigation of carbon–carbon composite brake pads in wet and dry sliding wear conditions

Purpose – The purpose of this study was to investigate wear behaviours of brake pads produced from carbon–carbon (C/C) composites in both wet and dry friction sliding conditions. Carbon is probably the most remarkable element in science and also C/C composites are a family of advanced composite materials. They are the most advanced form of carbon and consist of fibre based on carbon precursors embedded in a carbon matrix. In the present work, wear test specimens were prepared according to the related standards and they were exposed to pin-on-disc wear testing in wet and dry sliding conditions with different loads as 10, 20, 30 and 40 N with 1 m/s constant sliding speed. Wet friction process was conducted on all specimens by means of rain water collected from the nature. Design/methodology/approach – Pin-on-disc wear test tribology lubrication was used. Findings – Mechanical and physical property measurements of C/C composite brake pad materials: hardness, modulus of elasticity, density and water absorptio...

Wear behaviour investigation of wheel/rail interface in water lubrication and dry friction

Purpose – The aim of this study is to calculate the coefficient of friction of wheel/rail interface in both water lubrication and dry friction conditions.Design/methodology/approach – Specimens taken from wheel and rail used in railway transport were exposed to pin‐on‐disc wear testing with 10, 20, 30 and 40 N loads. The disc took the place of the rail and the pin that of the wheel in wear tests, and rain water was fed to the disc/pin interface with a three drops/min speed in wet friction conditions. The coefficient of friction and weight loss values of specimens were determined and types of wear mechanism were characterized.Findings – It was observed that the friction coefficient decreased in wet sliding experiments, so smaller values were calculated in wet friction conditions than those of dry friction conditions for wheel specimens. However, this decrease was more drastic for rail specimens. Weight and volumetric loss values of rail materials were lower than those of wheel samples.Originality/value – T...

Investigation of Mechanical Properties of MIG Brazed DP 600 Steel Joints Using Different Working Angles

Abstract In this study, dual phase (DP 600) steel plates with a thickness of 1 mm were joined by copper-based (CuAl8) wire using gas metal arc brazing technique. Specimens were prepared in butt joint form. Brazing operations were done at four different working angles: 50°, 60°, 70°, 80° and 90°, respectively. CuAl8 wire consisted largely of copper served as the filler metal. After completing the brazing operations, the tensile properties as well as the micro- and macro-structures of the joints were analyzed in order to investigate the joinability of DP 600 steel using gas metal arc brazing technique.

SAC METAL ŞEKİLLENDİRMEDE MUKAVEMET ARTTIRMA VE SONLU ELEMANLAR ANALİZLERİNİN DİNAMİK TESTLER İLE KARŞILAŞTIRILMASI

Bu calismada, beyaz esya sanayide yatay eksendeki kapaklarin acilip kapanmasini ve istenen seviyelerde dengede durmalarini saglayan yayli bir mentese mekanizmasi ele alinmistir. Mentesenin montajlanacak oldugu urunun geometrik sinirlari, calisma sartlari ve calisma araliklari tanimlidir. Menteseyi olusturan her bir parca icin detayli cizimler “SolidWorks” yazilimi yardimi ile yapilmis, 3d model olusturulmustur. Calisma esnasinda mentese mekanizmasi acma kapama omur test cihazi ile test edilmis ve deformasyona ugrayan parcalar belirlenmistir. Deformasyona ugrayan parcalarin sonlu elemanlar analizleri “SolidWorks Simulation” ile yapilmis, test sonuclarinin analiz verileri ortustugu gozlenmistir. Deformasyona ugrayan parca uzerinde geometrik iyilestirme yapilarak sonlu elemanlar analizleri ile yapilan iyilestirmenin sayisal karsiligi degerlendirilmis, alinan sonuclar laboratuvar testleri ile karsilastirmali olarak incelenmistir.

Microstructural Investigation of SPA-C Steel Sheets Used in Railway Vehicles in Resistance Spot Welding

This paper presents an experimental study on resistance spot welding of SPA-C steel sheets used in side wall and roof in rail vehicles. SPA-C steel sheets having 2.3 mm thicknesses were joined by using resistance spot welding as lap joint. A timer and current controlled resistance spot welding machine having 120 kVA capacity and a pneumatic application mechanism with a single lever was used to prepare the specimens. Welding periods were chosen as 5, 10, 15, 20, 25 and 30 cycles and also welding currents were increased from 6 kA up to 14 kA by rise of 0.5 kA. The electrode force was kept constant at 6 kN. The micro and macro-structures of prepared welding specimens were investigated by means of an optical microscope and scanning electron microscope (SEM) in order to see the joinability of SPA-C steel sheets by resistance spot welding.

Effect of Welding Current on Tensile-Peel Loading of Welding Joints in TRIP 800 and Micro-Alloyed Steels in Resistance Spot Welding

Effect of Welding Current on Tensile–Peel Loading of Welding Joints in TRIP 800 and Micro-Alloyed Steels in Resistance Spot Welding V. Onar, S. Aslanlar and N. Akkaşc,∗ Metallurgical and Materials Engineering Departments, Faculty of Engineering, Sakarya University, Sakarya, Turkey Manufacturing Engineering Departments, Faculty of Technology, Sakarya University, Sakarya, Turkey Mechanical Engineering Departments, Faculty of Technology, Sakarya University, Sakarya, Turkey

Microstructural Investigation of IF Steels Joined by Metal Inert Gas Brazing

In this study, interstitial-free (IF) Erdemir 7116 and galvanized Erdemir 1315 steels having 1.0 mm thickness were joined by metal inert gas (MIG)-brazing method. CuAl8 wire was used as filler material. The specimens were cut in 200 mm × 200 mm dimensions and joined by using 40, 45, 50, 55, 60, 65 and 70 A currents both in butt and overlap joint forms. Having prepared the joints, all specimens were exposed to tensile test according to TS 138 EN 10002-1 standard. Micro and macro-structure investigation of samples were performed by optical microscope and scanning electron microscope (SEM). The matrix structure and the other phases occurred during brazing process were characterized and the effects of them on mechanical properties of joints were discussed.

Microstructural Investigation of MIG-Brazed 304L Stainless Steel Joints

In this paper, austenitic 304L stainless steel plates having 1.0 mm thickness were joined by copper-based CuAl8 wire in gas metal arc brazing technique with 100 % Ar gas as a protective atmosphere. Specimens were prepared in butt and overlap joint positions. The metal inert gas (MIG) brazing operations were done with seven different arc voltages and weld currents as 40, 45, 50, 55, 60, 65 and 70 A. CuAl8 wire composed largely of copper serves as the filler metal was used. Owing to the low fusion temperature of the filler metal (900\(-\)1,100 \(^{\circ }\mathrm{C})\), no fusion of the base metal takes place in MIG-brazing. The 1,500 \(^{\circ }\mathrm{C}\) fusion temperature of the base metal was not reached. A solid joint between the workpieces was brought about by diffusion. Having accomplished the brazing operations, micro and macro-structures of joints were investigated by optical microscope and scanning electron microscope (SEM) in order to see the joinability of stainless steels by gas metal arc brazing technique.