No abstract

Temperature is the main effective process parameter in the warm deep drawing (WDD) process to improve the formability of light-weight engineering materials, and this feature requires the accurate measurement and assessment of temperature for process stability. In this study, an evaluation of the WDD process was conducted according to the forming temperature curves (FTCs) characterized from work piece temperatures instead of tool temperatures, as usual. To achieve this goal, a special index material was developed to accurately obtain FTCs from the work piece material under closed and heated tool conditions. The differences of temperature on work piece material are required to define temperatures by curves. The characteristic behavior of these curves was investigated under non-isothermal WDD of AA 5754-O. In the experimentation stage, the process parameters, namely FTC, blank holder force and punch velocity, which assure successful deep drawability, were determined according to the failure-free cups by analyzing wrinkling and tearing conditions and minimum cup height parameters as output parameters. As the next step, optimum conditions were investigated by evaluating the cup volume and springback parameters. As a general conclusion, approximately 330 • C in the flange-die radius region and 100 • C in the cup wall-punch bottom region are the ideal optimum temperatures for the warm deep drawing process.

This study examines the abrasive wear behavior of nano-sized steel scale on the CuZn35Ni2 Soft material. CuZn35Ni2 Soft material was used as a sample, and the three-body wear mechanism formed by nanoscale particles mixed with lubricating oil was investigated using a ball-on-flat tester. Three different loads, three different sliding speeds and three different environment variables were used in the experiments. A lubricant containing 0.15 and 0.3 wt.% nanoscale and a non-abrasive lubricant was used to form the medium. The experimental results were obtained as mass loss, wear depth and friction coefficient and the wear surfaces were examined using scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDX). The analysis of variance method was used to determine the effect of independent variables on the results. As a result of the study, it was concluded that the most effective parameter for mass loss and CoF was the environment, and the most effective parameter for the depth of wear was the load. It was concluded that there might be a difference of up to 10% in the coefficient of friction between the experiments and the predicted values. Still, in general, the predicted values and the experimental results agree.

The material S235JR was spray-coated with iron-based chromium carbide in the present study. The effects of the initial surface roughness on slurry erosion were investigated. Samples with a rough surface and polished surface were used. The impact of particle concentration, impact velocity and impact angle was studied on the slurry erosion characteristics in terms of mass loss, surface roughness and surface temperature. In addition, the surfaces were analysed using a scanning electron microscope (SEM). Further, the estimation equation has been derived using response surface method (RSM) based on the data obtained in the study. The results show that velocity and concentration are the key factors in determining the mass loss and surface temperature while the impact angle has a relatively minor role. Mass losses in rough samples ranged from 8.8 mg to 40 mg; in polished samples, the range ranged from 5.6 mg to 10.9 mg.

Metal matrix composites (MMCs) are materials used in a large range of engineering applications. In this paper, the relatively low-cost stir casting is evaluated with the use for Silisyum Carbite (SiC) as reinforcement and Al7075 alloy as matrix to produce MMCs with varied reinforcement from 10% to 18%. The produced composites were examined, and their wear behavior was investigated. The results showed that the mechanical properties of the MMCs decrease with the increase of the mass percentage of reinforcement and compression.