Papers by Keyword: Insert

Abstract: In this paper, a new concept of combination degree (CBD) is proposed. And the CBD between nylon and insert in the pipe wrench is investigated using ANSYS .Then studied the effects of factors on the CBD, such as load, elastic modulus, friction coefficient and behavior of contact surface between the nylon and the steel insert. The results indicate that as the load increases from500Nm to1500Nm, the CBD declines from4.92mm-1 to 1.23mm-1, which presents the combinative characteristics become worse. However, with the elastic modulus and the friction coefficient increases respectively, the CBD also increases. When the elastic modulus is 8000MPa, its CBD goes up to1.78mm-1. As the friction coefficient ranges from 0.1 to 0.5,the CBD increases from1.56mm-1 to 2.32mm-1.In addition, different behaviors of contact surface between the nylon and the insert have different effects on the CBD. When such behavior of contact surface is bonded, its CBD is the highest, 3.31mm-1, but when such behavior of contact surface is standard which means that if the separation between the nylon and the insert occurs, the normal pressure equals zero. And its CBD is the lowest, 1.78 mm-1.

Abstract: The resistance spot welding between commercially pure titanium and stainless steel was achieved using an aluminum alloy insert. The interfacial microstructure and mechanical properties of the joint were investigated. The maximum tensile shear load of 5.38 kN was obtained from the Ti/SUS304 joint welded at the welding current of 10 KA. The results reveal that the property of the Ti/SUS304 joint can be improved by using an aluminum alloy insert between Ti and SUS304 sheet.

Abstract: Inserts are used to transfer localized loads to structures made of sandwich composites. Stress concentrations near inserts are known to cause failures in sandwich panels. Experimental insert pull-out tests show that the load to failure can vary by 20% between batches of sandwich panels. Clearly, uncertainties in the mechanical properties of core and adhesive potting materials have to be accounted for in the optimal design of inserts in sandwich composites. In this paper, we use an one-dimensional computational model of an insert in a homogenized honeycomb sandwich panel to explore the utility of reliability methods in design. We show that the first-order reliability method (FORM) produces accurate estimates of loads that lead to low failure probabilities. We also observe that FORM is sensitive to the failure criteria and may not converge if the failure surface is not smooth and convex.

Abstract: To keep the k-anonymized dataset consistent with the original dataset in real time, the increment update algorithms basing on Semantic Similarity Degree for the k-anonymized dataset are presented. For each update operation on original dataset, the position of the tuple to be updated is located firstly on k-anonymized dataset by Semantic Similarity Degree and then the corresponding update operation is processed. The increment update algorithms not only guarantee k-anonymized dataset updating with original dataset simultaneously, but also avoid big changes in k-anonymized dataset.

Abstract: The influence on the wear properties of ductile iron with Cr-containing steel inserts has been investigated before and after austempering. The microstructure of locally reinforced ductile iron, with and without an austempering treatment, has been characterized using optical microscopy, scanning and transmission electron microscopy and secondary ion mass spectrometry. The introduction of such inserts during casting leads to the precipitation of carbides M3C, M7C3 and M23C6 (M stands for Fe and/or Cr) inside the inserts and to M3C and M7C3 in the region surrounding the inserts. After austempering, a partial dissolution of these latter carbides and transformation of the matrix to ausferrite occur. The wear properties of these materials have been evaluated under reciprocating sliding motion using cylinder-on-disc line contact configuration. The results of the present investigation show a better wear behavior of the reinforced material related to the microstructural changes observed.

Abstract: Particle reinforcement via the insertion of hard particles is a promising process in materials reinforcing. Particle-reinforced spheroidal graphite martensitic cast iron (SGMC), in which mixed particles of cermet and cemented carbide are dispersed, was achieved by an insertion process. A four-point bending strength test was applied to evaluate the particle composite material. An evaporative pattern process was used on the bending-test specimen to form a composite layer in the central part. Using a combination of three sizes of cermet particles and two sizes of cemented-carbide particles, the bending strength was found to increase with each small-particle combination. The Weibull coefficient m of the four-point bending strength of the particle-reinforced composite material (PRCM) ranged from 4 to 13, and m was large in the specimen with large bending strength.

Abstract: A tungsten carbide insert is produced during ductile iron foundry practice to increase the surface hardness of the material. The insert is ensured with the help of a critical quantity of a binder, around 3 weight percent of sodium silicate, previously mixed with the tungsten carbide powder. The binder is verified to form a film around the tungsten carbide particles and bridges amongst these enveloped particles; these films and bridges are replaced by the ductile iron melt during the molding cavity filling. After solidification, a sound inserted layer is formed, composed of tungsten carbide particles in a tungsten enriched cast iron matrix. In the absence of the binder addition to the tungsten carbide powder no inserted layer is produced. The surface hardness of the inserted test pieces is close to 500VHN/4.9N and the respective thickness is around 2.5 mm. The characterization of the effect of the sodium silicate in the mixture has been the main purpose of this work

Abstract: The grid technique is an experimental method for measuring the deformation in hot rolling. An AA3004 sample -fitted with an insert - was rolled in a single hot rolling pass at 400 oC. The insert was hand engraved with a 1x1 mm grid and the analysis of the image of the deformed grid enabled the calculation of the components of the deformation gradient tensor. In order to prevent relative motion between the insert and the work-piece, four steel pins were used; after the test no detachment was observed between insert and sample. The temperature was monitored during rolling using two embedded thermocouples, one close to the surface and the other on the centre-line of the slab. The commercial finite element (FE) code ABAQUS was used to build a threedimensional model of the rolling process. The recorded temperature was compared with the FE values evaluated after tuning the heat transfer coefficient. The FE model was run several times with different friction coefficients and the deformation gradient checked against the experimental measurement of the deformed grid in order to obtain the optimum friction coefficient. The experimentally determined deformation gradient and the measured temperature agreed well with the numerical values.

Abstract: A continuous effort is being devoted to study the feasibility of improving the wear resistance of ductile iron components through an insertion of a hard metal powder layer during the casting process. Tests have been run to evaluate the wear resistance of the inserted material, compared to a non inserted ductile iron. The tests have been run in accordance with ASTM G65-94, which specifies the so-called rubber wheel test. Three different kinds of material have been tested: a non inserted ductile iron, an inserted ductile iron in the as-cast state and an inserted ductile iron with a rectified surface. The tests have been run gradually; each test piece has been taken out from the test apparatus and weighted at different intervals, from 200 to 6400 wheel revolutions (or 0.1 to 4.4 km of sliding distance); the results obtained show that the non inserted ductile iron presents a loss of weight fifty percent higher than the inserted material. The analysis of the surface of the test pieces after the wear tests has been run under stereo and scanning electron microscopy. The non inserted ductile iron test piece surface has shown an uniform waviness with a wavelength around half a millimeter and under higher magnification much finer wear marks have been observed. The inserted ductile iron test piece surface has shown the same relief with half a millimeter wavelength but a significant difference has been noticed: the fine wear marks have been observed in the metallic matrix of the insert but they stop in the neighborhood of the tungsten carbide particles, leading the authors to propose that these hard particles remained unchanged until the metallic matrix supporting them has been sufficiently removed to cause the respective extraction; this behavior should explain the smaller weight loss rate of the inserted material.

Abstract: A diffusion brazing of aluminium alloy A6061 was preformed using a Ag-28Cu insert to conduct eutectic brazing. Interface behaviors of the brazed joints were observed after brazing at 450-560°C. The tensile property of the brazed joints was also examined. During diffusion brazing of Al6061 alloys with Ag-28Cu insert, eutectic melts were formed by eutectic reaction between Al6061 and Ag-28Cu insert. It was found that the reaction layers composed of two phases were formed at the interface between Al6061 and Ag-28Cu insert. EPMA analysis revealed that two phases in the reaction layers consist of Ag-rich phase and Cu-rich phase. The tensile strength of the joints brazed at 560°C for 30min was 160 MPa.