Materials Science Forum Vol. 941

Abstract: Cemented carbides are the most common cutting tools for machining various grades of steels. In this study, wear behavior of two different cemented carbide grades with roughly the same fraction of binder phase and carbide phase but different grain size, in turning austenitic stainless steel is investigated. Wear tests were carried out against 316L stainless steel at 180 and 250 m/min cutting speeds.The worn surface of cutting tool is characterized using high resolution scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES) and 3D optical profiler.The wear of cemented carbide in turning stainless steel is controlled by both chemical and mechanical wear. Plastic deformation, grain fracture and chemical wear is observed on flank and rake face of the cutting insert. In the case of fine-grained, the WC grains has higher surface contact with the adhered material which promotes higher chemical reaction and degradation of WC grains, so chemical wear resistance of the composites is larger when WC grains are larger. The hardness of cemented carbide increase linearly by decreasing grain size, therefore mechanical wear resistance of the composites is larger when WC grains are smaller.

Abstract: The sin² ψ method [1] is conventionally used well as how to measure non-destructively the residual strain and stress states of polycrystalline materials by X-ray diffraction. In the conventional method, there are Dölle-Hauk method [2] and Winholz-Cohen least squares analysis [3] as the determinations of the strain and stress states for limiting the influence of measurement errors. Many researches are made about the statistical error in those methods. In recent years, use of the X-ray stress measurements with two-dimensional detector from the conventional method is spreading. One of the measurements is called the cos α method. The measurement errors have attracted a great deal of attention for users as the spreads. Therefore, the basic equations and determinations of the strain and stress states are examined. The confidence intervals of measured stress by the cos α method. The research and development is performed for the the cos α method which took the influence of measurement errors into consideration.

Abstract: In this study, the diffraction rings were measured point by point all over the head of rail sample which was used in service, and shearing stresses with respect to the depth direction were determined using the generalized cosα method. The full width at half maximum was also estimated from the diffraction ring.

Abstract: In recent years, the monitoring of the energy consumption in the industrial processes shows a growing interest due to its strong fallout on environmental pollution and environmental sustainability. On this purpose, this paper deals with the design of a portable Digital Acquisition system (DAQ) tailored for monitoring the energy consumption in different classes of welding machines. The proposed system is a multichannel DAQ able to measure the overall power consumption at the input of the machine (including those relative to the secondary equipment present in the welding process as gas pumps, chillers, etc.) together with some other physical quantities in output (which depend on the features own of the welding machine). The results of these measurements will be deeply investigated and, by a proper metallurgical analysis, related to the mechanical characteristics of the welted joint. Some results on preliminary measures performed on a Tungsten Inert Gas (TIG) welding machine in a real industrial welding process will be shown in the paper.

Abstract: Traceability has an enormous value for companies, but especially for those working in the regulated environment. It plays a special role in the field of pharmacy with respect to manufacturing, controlling and distributing batches of drugs. Through the guidance of Good Manufacturing Practice (GMP) traceability should be ensured. An increasing number of pharmaceutical companies are member of one of the global pharmacopoeias (United States Pharmacopeia, European Pharmacopeia and Japanese Pharmacopeia). The specifications of these pharmacopoeias describe the best practice in documentation, control, qualification and risk management. But however, the pharmacopoeias are written very generally and do not distinguish between the vendors of the analytical instruments. Here, we analyze how chromatographic analyses and data acquisition rely on a specific vendor of the device and the chromatography data system (CDS), the controlling software. We present a way to compare the data acquisition of different CDSs communicating with HPLC instruments. A newly developed software called Data Collector allows the acquisition of data from a HPLC detector parallel to the controlling CDS in the same run. Two HPLC systems and two different CDSs using a well defined sample standard have been tested. The direct comparison of the acquired data precludes unexpected data manipulations of both tested CDSs and shows that there are primarily deviations between the CDSs due to time variations only which depend on the sampling rate. All in all the Data Collector can be used for the traceability of data acquisition.

Abstract: The availability of reliable fatigue data is of continuous and often urgent need. The paper to be presented therefore intends to show how the potential of non-destructive testing methods, digitisation in metrology as well as signal processing can be combined in order to achieve a significant gain in information concerning the fatigue behaviour combined with a reduction of required experimental effort and cost. The new SteBLife approach is an enhanced short-time calculation method developed at the Chair of Non-Destructive Testing and Quality Assurance at Saarland University, which takes into account that a material’s elastic-plastic reaction and hence relationship is non-linear. With respect to a test strategy, the number of fatigue experiments required to determine a material’s complete S-N-curve can be limited to three to five tests only (SteBLife_mtc, mtc: multiple tests, trend curve and SteBLife_msb, msb: multiple tests, scatter bands) in cases that mean values and/or complete scatter bands of S-N-curves are required. If a trend S-N-curve is sufficient, the effort can be reduced to one single test only (SteBLife_stc, stc: single test, trend curve) with a special step-shaped specimen. This leads to a significant improvement in efficiency when compared to the conventional way an S-N-curve is determined where a minimum of 15 fatigue tests is required. Within the work to be presented the SteBLife method is demonstrated for normalized SAE 1045 (C45E) steel.

Abstract: 3D imaging techniques have an enormous potential to understand the microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this conference paper we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. We demonstrate showcases of ceramics and composite materials, where microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. We present in situ analysis of the damage evolution in an Al/Al₂O₃ metal matrix composite during tensile load and the identification of void formation (different kinds of defects, particularly unsintered powder hidden in pores, and small inhomogeneity’s like cracks) in Ti64 parts produced by selective laser melting using synchrotron X-ray refraction radiography and tomography.

Abstract: We investigated the consistency of four methods by analyzing the distorted Debye rings with various stress states. Firstly, the distorted Debye rings were generated under various uni-, bi-and tri-axial stress states by using the fundamental stress-strain relationship in two dimensional X-ray stress analysis theory. Secondly, we performed reverse analysis of stress states in the frameworks of sin²ψ and cosα methods from the simulated Debye rings. Moreover, the profiles of simulated Debye rings were Fourier transformed and the stress states were calculated in accordance with the obtained 1st and 2nd order Fourier coefficients. As a result, it was confirmed that all these methods provide the same stress values. That is to say, all these methods are consistent. Therefore, we can guarantee the validity of choosing any appropriate method considering the geometrical restrictions of experiment.

Abstract: Tons of composite trimmings are regularly generated as a result of current production methods in commercial aircraft wing component fabrication. Specific to this proposal, a local facility produces trimmings that range in thickness from about a centimeter to over two inches thick and varying widths from a few inches to six inches and lengths up to five feet. Reducing the cost of the disposition of these trimmings and a reduction of waste to landfill are the primary motivations for this work. A processor was devised that both separates fiber and reduces volume. This device is a vertical crusher/roller into which the ‘boards’ are inserted. An initial cogged wheel delaminates much of the board. Secondary wheels and hammers crush the matrix. The resulting matrix is captured at the bottom, while the fibers are pulled off to a side roller. Preliminary testing of a prototype indicates that a composite board takes 156 ksi to initiate delamination in bending. A sub-size device with components was designed and built. The device was designed in the fall of 2017 and constructed over the winter. By spring the system was operational and test data was generated for the processor. Test parameters include percent and amounts of recovered fiber, processing rates related to all the composite constituents, packing volumes, and overall energy management. A report was generated in concurrence with our MET489 Senior Project capstone course by the end of the current academic year.

Abstract: This paper presents the experimental results on the strength and axial behavior of rectangular steel tube columns filled with cellular lightweight concrete (CLC) under axial compression. A total of 24 specimens, including 6 reinforced cellular lightweight concrete (RCLC) columns and 18 cellular lightweight concrete-filled steel tube (CLCFT) columns are investigated. The nominal dimension of the rectangular columns are 150×75 mm in cross-section and 750 mm in height. The parameter used in all tests are the ultimate compressive strengths of the CLC, which are 15 MPa, 20 MPa and 25 MPa, and the wall thicknesses of steel tubes, which are 3.0 mm, 4.5 mm and 6.0 mm. All specimens are prepared and loaded concentrically in axial compression to failure. The results of these tests demonstrated that the CLCFT columns have a linear behavior up to the approximately 80-90% of their maximum compressive load. Then, the behavior of the columns is nonlinear. The nonlinear behaviors are due to the crushing of the concrete core and local wall buckling of the steel hollow tube. In addition, it is found that the CLCFT columns have high axial deformability at the failure when compared to the reference RCLC columns. Finally, by comparing the maximum compressive load of the test results with those obtained from the ACI composite design equation, the comparison results show that calculation formula in ACI code can be applied to compute the axial capacity of CLCFT columns under axial compression.