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Carboniferous bituminous coals of the Zonguldak Basin have been mined for over a century. Due to underground mining activity, there have been several fatal incidents related to gas explosions. The gas content of the coals varies greatly in the basin mainly based on coal maturity (rank), increasing with increasing coal depth. In this study, we report a map for coal depth and coal rank in the Kozlu-Üzülmez-Karadon districts of Zonguldak Basin with hope the that it would aid coal gas exploration/exploitation and also coal gas degassing efforts for safer underground mining production in the Zonguldak Basin. [ABSTRACT FROM AUTHOR]

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Tool steels are extensively used in sheet metal forming dies in order to prolong the life of dies and reduce the cost of production. Powder metallurgy tool steels are also alternatively preferred because of their low-risk metallurgical behavior owing to their compositions by which bulk steel would be difficult to produce, such as high amount of carbides or high alloying elements. Such advantage is desired if the steel has a narrow range of fine grain sizes and is less metallurgically affected by the heat treatment process due to having large surface area of fine grains. In this study, ASP® 2012 powder metallurgy steel containing high amounts of Si, Cr, Mo and W was selected for boronizing by the boron-giving thermochemical process. The boride layers on the surface of ASP® 2012 tool steel were metallographically characterized by various characterization techniques including adhesion strength test, SEM and XRD. The effects of corrosion kinetics and chemical composition of steel on the amount and types of boride layers formed on P/M steel of ASP® 2012 after powder-pack boriding were investigated. The results indicate that, according to the Rockwell-C indentation test, the best adhesion in the boride layer was obtained in samples borided at 850°C for 4 h, while the worst adhesion was obtained in ASP® 2012 steel boronized at 950°C for 4 h. Corrosion rates of boronized ASP® 2012 steel were decreased compared to nonboronized ASP® 2012 steel. [ABSTRACT FROM AUTHOR]

Tool steels are generally preferred for shaping and blanking dies in sheet forming industry. A mild heat treatment is needed to bring about the properties needed for long lasting operational characteristics such as low wear rate, high hardness and durability. Blanking and deep drawing processes, plastic injection moulding and various machine components are typical applications of such steels, which can also be produced by powder metallurgy such as ASP®2012 class tool steels with a high hardness value as much as 63 HRC. In this study, boronizing was carried out on ASP®2012 tool steels and diffusion kinetics were investigated for different temperatures (1123, 1173, 1223 K) and holding times (2, 4 and 6 h) in Ekabor-2 powder. The microstructural development and phases in the specimens were investigated by using optical microscopy and Shimadzu XRD-6000 brand X-ray diffraction using CuKα (λ = 1.5406 Å) radiation, respectively. The kinetics study showed that high alloying elements retards the diffusion in the bulk however borides of W2B, Mo2B and CrB were observed within the hard boride layer on ASP®2012 tool steel surface. [ABSTRACT FROM AUTHOR]