Advanced Materials Research Vol. 739

Abstract: The paper deals with solutions to particular process problems in production of thin sheets of special nickel and iron-based alloys. Experiments were focused on trial operation of a new melting furnace, on hot rolling of feedstock from experimental heats and on fine-tuning hot and cold rolling processes with the aid of numerical modelling in DEFORM 3D software. The paper also gives description of results of FEM simulation of cold rolling of strips. A FEM model of the cold rolling process with front and back tension was developed. In order to describe the behaviour of nickel alloys in the FEM simulation, a specific material model was proposed. This material model combines the material data obtained from Rastegaev compression test and the results of thermodynamical calculation from JMatPro software.

Abstract: Three types of copper traces for PCBs were investigated: 1) 2.5 μm thin film lines (Ti;Cu;Ni) on aluminium and ceramic (Al₂O₃) substrates; 2) 2.5 μm thin film lines (Ti;Cu;Ni;Au) on ceramic (Al₂O₃) substrates; 3) 15 μm traces (Cu;Ni) on polyimide substrate for high density interconnection PCBs. The width of all types of traces was varying in the range of 100-500 μm. The set of temperature-current diagrams for different PCB scenarios are presented and analyzed. The temperature caused by Joule heating was measured using IR camera Flir A40 with macrolens. For different cases the current was set in the range of 0.1-3 A; the measured temperature was in the range of 20-140 °C. The close agreement between the results measured and simulated with ELCUT software tool was achieved.

Abstract: nevitable part of bearing steel processing is soft annealing. Hot formed semi-products usually have unfavorable structure for machining. The lamellar pearlite in semi-products is transformed to globular pearlite by soft annealing. This long-lasting process is usually in practice carried out by annealing in furnace for tens of hours. Furnace processing effectiveness is very often raised by increasing amount of batch mass for one annealing. The time needed for soft annealing is then significantly extended by period necessary for homogeneous heating and slow cooling of the heat. Presented paper shows different way of carbide spheroidisation and steel softening using induction heating of 100CrMnSi6-4 bearing steel. The new process of soft annealing by induction heating is achievable in minutes. This method is appropriate especially for small semi-products and for continuous processes.

Abstract: Finite element analysis of superplastic forming process for a hollow sandwich structure of aluminum alloy was carried out with MARC software, which can predict the thickness distribution of the structure, and optimize the pressure-time curve to control the maximum strain rate, which provided reference basis for the forming pressure of the subsequent experiment.

Abstract: The aim of this contribution is to test the suitability of selected types of tool steels used for manufacturing of injection molds. Experiments were realized by the simulation of adhesive wear using laboratory equipment Amsler, which allows the testing of grinding pairs. Evaluated grinding pairs consisted of tool steel and two types of roundels. Tested polymeric materials were based on pure PA6 and PBT filled with short glass fibers, prepared by mixing process in twin screw extruder. The wear of five types of tool steels were evaluated by weight decrease before and after the experiment, while changing the friction coefficient of grinding pairs, material of grinding pairs and sensing the roughness of steel before and after wear.

Abstract: Support vector machines (SVMs) are a promising type of learning machine based on structural risk minimization and statistical learning theory, which can be divided into two categories: support vector classification (SVC) machines and support vector regression machines (SVR). The basic elements and algorithms of SVC machines are discussed. As modeling and prediction methods are introduced into the experiment of microwave calcining AUC, the better prediction accuracy and the better fitting results are compare with back propagation (BP) neural network method. This is conducted to elucidate the good generalization performance of SVMs, especially good for dealing with the data of some nonlinearity.

Abstract: Weave density , yarn size , texture cycle , and so on how to affect honeycomb weaves property and principle are analyzed , with weaving honeycomb textile based on Love structure model of non-plain weave fabric , different density , different organization cycle , different yarn count and different tension . Analysis results is that main factor of affecting honeycomb weaves property is weave cycle yarn numbers .When weave cycle yarn numbers become more big , honeycomb weaves effect is more obvious . Otherwise , under some degree , weave density and yarn size cause to honeycomb weaves effect is not obvious .With experiment and analysis , main reason which is to cause to produce honeycomb weaves is that different yarns of weaves are interlaced according to yarns numbers can cause to different yarns structure to change .

Abstract: The effects of rheocasting times on the hot tearing defect in semi-solid die casting of aluminum A201 alloy have been investigated. This study found that no hot cracking formed in the semi-solid A201 alloy parts at a rheocasting time of 10 seconds, implying that the hot tearing suscepability (HTS) index value is zero. Moreover, the HTS index values for all semi-solid casting conditions were lower than those found in conventional casting samples. The microstructure of the as semi-solid casting parts consisting of non-dendritic structures and smaller grain size helped to improve the hot tearing resistance of aluminum A201 alloy. These results support the feasibility of semi-solid die casting of aluminum A201 alloy by using Gas Induced Semi-Solid (GISS) technique.

Abstract: A three-layer Ti-Si graded coating was fabricated on a commercially pure titanium substrate by laser cladding with Ti-5.8 at%Si, Ti-9.0 at%Si and Ti-13.5 at%Si mixed powders. The microstructure of the three layers comprised Ti-Si solid solutions (Ti) and the Ti₅Si₃ compound. As the silicon content was increased, the microstructure along the direction of deposition underwent a series of changes, including replacement of the (Ti) phase by the primary Ti₅Si₃ phase, and a change of the (Ti)/Ti₅Si₃ eutectic growth from lamellar to anomalous.

Abstract: The basic hypothesis of the article focuses on the ploughing effect from the cutting process during the course of making holes by drilling into austenitic stainless steel X5Cr18Ni9. The problem with drilling holes with a diameter of D_w=3 through 10 mm. The article presents the results from experiments where stainless steel X5Cr18Ni9 was drilled. Based on the cutting tests, cutting speeds of 40 to 60 m/min, feed rate of 0.04 to 1.2 mm and screw drill carbide monolite.