Papers by Keyword: Pure Titanium

Abstract: The main purpose of this paper is to analyze the values of the temperature after turning of pure titanium and its alloy, Ti6Al4V, as function of different cutting parameters (rotational speed, feed and depth of cut). Based on an infrared thermometer measurements for dry turning, with un-coated carbide insert, graphically dependencies of temperature as function of the cutting parameters are presented for the both materials.

Abstract: To produce functional cups by press forming, clad cups with a corrugated structure with voids like the cross section of corrugated cardboard were formed. Deep drawing, which is one type of press forming, is a plastic processing technology that forms thin sheets into three-dimensional containers. In the experiment, pure titanium TP270 and ultra-low carbon steel SPCC were used as test materials. The blank sheet thickness was 0.3 mm and the diameter was 80 mm to 90 mm. To form the corrugated cup, the roller ball die with steel balls installed on the shoulder of the die was prototyped. The steel balls were made of bearing steel JIS-SUJ2 and had diameters of 6.4 mm and 7.5 mm. The corrugated clad cup was formed by the composite die combined with a conventional die. Three conventional dies and two roller ball dies were used to obtain two corrugated layers with voids. The lubricant was a tool oil containing molybdenum disulfide powder. The sheet thickness strain distribution and residual stress distribution of the cup were evaluated. No destruction of the cup occurred during deep drawing. A regular wavy structure was observed in the cross section of the cup. The maximum reduction in the cup thickness was approximately 10 %. The residual stress on the outside of the cup was tensile stress from the bottom to the opening of the cup. The composite die made it possible to form a functional cup.

Abstract: Taking the advantage of its low density, high specific strength and strong corrosion resistance, titanium and aluminum alloys have high marine adaptability and can be directly used in various marine engineering equipment that will expose to seawater or directly contact with seawater. The seawater heater has to withstand 90~120°C corrosion in seawater. This unique working condition makes titanium and aluminum alloys are superior materials which can significantly lower the heater construction cost. In this study, the technology of friction stir welding was used to join the dissimilar materials of aluminum alloy 6061 and commercially pure titanium by means of butt joint. High-speed steel stir rod was used for the friction stir welding, and a 2^o title was applied to the stir rod during friction stir welding. To discuss the influence of different rotating speeds and travel speed, the specimens were analyzed for their microstructure, mechanical properties, and elemental analysis was carried out followed by the friction stir welding. Experimental results showed that the best mechanical properties of the butt joint can be obtained by setting the rotational speed of 1000 rpm and the travel speed of 100 mm/min. After welding, grain refinement can be observed in the stirring zone. However, the grains in the heat-affected zone had become larger, and there had a tendency of hardness decreasing, causing failure in this area during tensile testing.

Abstract: In order to increase strength while maintaining the ductility of material, pure titanium was improved through the thermomechanical treatment that combines rolling and heat treatment. The tensile properties of pure titanium treated by rolling and heating were investigated. Test material was JIS Grade 2. This material has a higher corrosion resistance. However, the strength of JIS Grade 2 is lower than that of JIS Grade 3. JIS Grade 2 with high strength while maintaining corrosion resistance is being developed. Techniques for improving the properties of materials with simple compositions are important. Thermomechanical treatment is used as a method for improving material properties. In the present study, the effect of thermomechanical treatment on the material properties of JIS Grade 2 was investigated. Rolling was performed at room temperature and the reduction ratio ranged from 70 to 90 %. The heating temperature was in the range of 300 to 700 °C. Heat treatment from 400 to 500 °C showed an increase in tensile strength while maintaining ductility. When the heat treatment temperature was 450 °C, the strength and elongation were approximately 600 MPa and 25 %. Tensile stress of JIS Grade 4 and the tensile strain of JIS Grade 1 were exhibited.

Abstract: The influence of different nitriding temperatures was investigated on the structures and mechanical properties of the treated specimens. Based on the research of nitriding temperature on the properties of pure titanium, the cause of the rresults can be discussed in this research. When the nitriding temperature is 1050°C, the cross-sectional hardness of the hardened layer reaches the maximum. At the same nitriding temperature, the bonding strength also reaches the maximum, which is related to the performance of the hardened layer. In summary, when the nitriding temperature is 1050°C, the nitriding of pure titanium can improve the overall performance.

Abstract: Structure and mechanical properties of pure titanium by combined processing of boriding and nitriding with different processing temperatures in the heating furnace have been investigated. The effect of combined processing temperature for 2 h on the structure and mechanical properties of the treated specimens. As a result of the examination, combined processing at all designed temperatures resulted in the formation of titanium nitride, where the content of the nitride depended greatly on the processing temperature. When the processing temperature is 1300°C, the cross-sectional hardness of the hardened layer reaches the maximum. At the same temperature, the bonding strength also reaches the maximum, which is related to the performance of the hardened layer. Based on these results, when the processing temperature is 1300°C, the combined processing of pure titanium can improve the overall performance.

Abstract: The paper contains the results of surface modification on the properties of the pure titanium Grade II, obtained by the SLM procedure. In the paper, the analysis of the results of physicochemical properties, such as pitting corrosion test and contact angle measurements and Surface Free Energy calculated were performed. Additionally, the microscopic observation with microchemical analysis, surface topography analysis using Atomic Force Microscopy, surface roughness measurements and wear test were performed too. The studies were carried out on three groups of samples in an initial state (1) (after mechanical treatment - mechanical grinding and polishing) and after surface modification by PVD method using CrN layer (2) and TiN layer (3). Based on the obtained results it can be concluded that the samples with TiN layer were characterized by the optimum properties.

Abstract: Industrial pure titanium (TA2) and Ti-6Al-4V (TC4) have been widely available for chemical equipment. However, the corrosion resistance changes during their post-fire performance. In this research, the electrochemical properties of industrial pure titanium and Ti-6Al-4V after heat treatment and different cooling methods were analyzed by AC impedance technique and dynamic polarization method. The results support two conclusions. Firstly, when the temperature is approximate to the phase transition point, for pure titanium and its alloys, water-cooling can obtain better corrosion resistance than air-cooling. With regard to pure titanium, its best corrosion resistance can be obtained at 800°C under water-cooling. For Ti-6Al-4V, its best corrosion resistance can be obtained when the temperature reached 910 °C under water cooling condition. Secondly, the corrosion current density under acid corrosion condition has risen compared with neutral corrosion condition. These results can provide some experimental data and theoretical basis for post-fire anticorrosion performance of titanium materials, and also support the safety, risk evaluation of titanium equipment.

Abstract: Pure titanium and its alloys are widely used in automotive industry, due to their high specific strength (strength/density) and excellent corrosion resistance, despite of their high cost. From point of view of machining, turning experiments of the pure titanium involve few input parameters (cutting speed, feed rate or depth of cut) and investigation of their influence on the response parameters of the cutting process (temperature in this case). Objectives of this study are to find the optimal combination of the input parameters, so that the temperature in turning of pure titanium to be minimum. In order to use a small number of experiments, two major tools, signal-to-noise (one of the three characteristic: nominal is the best, smaller the better or larger is better) and orthogonal array as statistical method can be used. For this study, a L₉ (3⁴) orthogonal array was considered adequate, so nine experiments was conducted using each factor (speed, feed and depth of cut) at three different levels.

Abstract: The cold rolling texture evolution as a function of strain path in pure titanium with initial typical recrystallized texture has been studied using viscoplastic self-consistent simulations. Three different strain paths, namely unidirectional rolling, two-step cross rolling and multi-step cross rolling have been employed to investigate the effect of strain path change on the evolution of deformation texture. The simulation results indicate that the activation of predominant prismatic slip in unidirectional rolling sample results in the formation of commonly cold rolling fiber texture RD//<10-10> in pure titanium, whereas the increased activity of basal slip over that of prismatic slip is responsible for the strong ND//<hkil> fiber texture in the two cross rolled samples.