Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
Browse
3 results
Search Results
Article Testing Corrosion Rates on Steel Piping in Geothermal District Heating(National Association of Corrosion Engineers, 2008) İnce, Umut; Toksoy, Macit; Güden, MustafaThe corrosion behavior of St-37 pipeline carbon steel (CS) in a geothermal district heating system was tested at two different fluid velocities. An experimental set-up, directly connected the the end of the transmission line of a geothermal well, was used to assess the corrosion of St-37 steel tensile test coupons prepared in accordance with ASTM E8 in geothermal fluid. The geothermal fluid entered the set-up with a relatively low velocity, 0.02 m/s, and then injected into the well with a relatively high fluid velocity, 9.6 m/s. It was observed that while the uniform corrosion rates were relatively low, pitting corrosion rate, mainly driven by the sulfate-reducing bacteria (SRB) activity, was relatively high and more pronounced at low fluid velocities. St-37 steel material is prone to the pitting type corrosion, thus a biocide chemical addition and the fluid velocity of 2 to 3 m/s in transmission line were recommended to reduce SRB activity to reduce the pitting corrosion rate.Article Izmir-balçova Jeotermal Doğrudan Isıtma Sisteminde Kullanılan St-37 Karbon Çelik Malzemesinin Değişik Akışkan Hızlarındaki Korozyon Davranışı ve Mekanik Özelliklerindeki Değişimler(TMMOB Makina Mühendisleri Odası, 2004) İnce, Umut; Toksoy, Macit; Güden, Mustafaİzmir-Balçova ısıtma sisteminde kullanılan St-37 çelik malzemesinin düşük (0,002 m/s) ve yüksek (9,3 m/s) akışkan hızlarındaki korozyon davranışları ve korozyon sonucu oluşan mekanik özelliklerdeki değişimler araştırılmıştır. Deney sonuçları, düşük akışkan hızlarında homojen dağılmış korozyon hızının azaldığını ancak çukurcuk korozyon eğiliminin arttığını göstermiştir. Çalışılan her iki akışkan hızlarında malzeme yüzeyinde oluşan korozyon tabakalarının yapısı mikroskobik ve elemental analiz yöntemleri ile detaylı incelenmiştir. Korozyon deneyleri ve mekanik test sonuçları kullanılarak çalışılan akışkan hızlarında malzemenin ömürleri tahmin edilmiştir.Article Citation - WoS: 7Citation - Scopus: 7An Iterative Numerical Method for Determination of Temperature-Dependent Friction Coefficients in Thermomechanical Model Analysis of Cold Bolt Forging(Springer Verlag, 2013) İnce, Umut; Güden, MustafaA set of temperature-dependent friction coefficients was developed to increase the accuracy of finite element (FE) simulations of cold bolt forging. The initially attained friction coefficients at different temperatures were calibrated with the iterations between the experimental and thermomechanical model extrusion test loads. The constant friction coefficient and the determined set of friction coefficients as function of temperature were then implemented to the simulations of the cold bolt-forging processes. Further calibrations and model validations were made based on the temperature measurements of the workpiece in the actual bolt-forging processes. To show the advantages of developed temperature-dependent friction coefficients, the loads of four different bolt-forging processes were compared with the thermomechanical model loads calculated using the constant friction and temperature-dependent friction coefficients. The modeling results indicated that the use of temperature-dependent friction coefficients in the FE simulations resulted in nearer temperature distributions and the loads of the workpiece during forging as compared with the use of a constant friction coefficient.