Advanced Materials Research Vols. 834-836

Abstract: The connecting pipe in solar hot water system is made by TIG welding of thin-walled stainless steel and copper. As the welding of stainless steel and copper belongs to dissimilar metal welding and their physical properties are very different, thus the welding process is difficult and it is likely to cause a variety of defects in the welding process. In this paper, ANSYS software is used to simulate the welding process of stainless steel and copper, and the residual stress distributions in the welding process are obtained. The results show that: at the end of the welding cooling, large residual stress (253MPa) is remained in the junction area of the starting and ending position of welding, which is close to the yield strength of material at the same temperature. Therefore, there will be greater deformation in the junction area and more cracks inside. Meanwhile, the stress distributions of stainless steel and copper tubes in the welding process are greatly different. Different volume changes emerge in two tubes, which are harmful to the welding seam and also leads to the unfitness of dimensional tolerance of welding parts, resulting in the scrapping of welding parts. The results provide references and theoretical basis for the welding technology of dissimilar materials.

Abstract: Tension-torsion experiments at 680°C and 850°C on thin-wall tube specimens of DD3 nickel-based single crystal superalloys were successfully completed. It shows that specimens have stress relaxation obviously and inelastic deformation accumulation phenomenon with different crystal orientation under asymmetric cyclic loadings. Based on the microstructure characteristics of nickel-based single crystal superalloys, a two-phase multi-cell microscopic mechanical model was established by finite element method to simulate the test with displacement. Numerical simulation studies showed that the matrix phase appeared plastic deformation accumulation at first and resulted in low cycle fatigue damage, but stress distortion occurred on the boundary with a single cell model under tension-torsion displacement loading, which is not consistent with experimental results. While using multi-cell model can avoid this phenomenon, it could be better to simulate stress relaxation behavior under asymmetric cyclic loading at elevated temperature and to study on stress weaken damage for single crystal superalloys.

Abstract: This essay direct at quenching craft of P110 oil case, makes 25MnV steel as study objective, considers geometric symmetry of oil case, analyzes chemical component of oil case, measures thermal conductivity, specific heat and convection coefficient, simulates the temperature field of the quenching oil case by finite element software, and receives the temperature field distribution and the change along thickness, the result closes to the date of fact. This is reference to establishment and prediction of quenching craft and next research of residual stress of quenched oil case.

Abstract: Drawing speed is one important process in production over-head line, deform 3d software is used to simulate the drawing process. The distribution of stress-strain and temperature in different drawing speed with die angle and friction coefficient was investigated. The results shows that the aluminum conductors can be used in high speed drawing when die angle, drawing speed and frication coefficient of first pass is about11~13 degrees, 4~6m/s and 0.08~0.10 respectively, the uniformity of stress-strain and temperature is better for producing good quality over-head wires with high cold-drawing speed.

Abstract: The primary goal of this research is the development of software system about functional gradient material process by laser. The system can be divided into several modules such as STL file loading and viewing, model slicing, filling path planning and process controlling. Path planning of FGM area is one key technology of system development because of one path must contain material information of functional gradient material. The material information planning methods of one-dimension and two-dimension functional gradient material were described respectively in this article. The material information of one-dimension FGM changes by layer along Z-axis, and the material information of two-dimension FGM changes by path in X-Y plane, especially, there is different change direction of FGM between inner loop and outer loop.

Abstract: As investment castings grow in size and complexity, control of wax pattern dimensions becomes increasingly important and difficult. Conventionally, mold design and dimensions are re-worked by trial-and-error procedures until casting dimensions are produced within acceptable dimensional tolerances, increasing the cost of the castings.Nowadays, numerical simulation is an efficient tool for mold design. However, one of the critical difficulties in using computer models for the simulation of wax injection process is the lack of material properties of the wax. Material property measurements were conducted in this study that can be used as input in Moldflow. Then, 3D numerical simulation could be applied in analysis with mold design of thin-walled wax pattern, with high dependability. Simulation results of filling time and the location of the air traps were analyzed. Consequently, best gate location and reasonable gate system were determined. The paper highlighted the effectiveness of simulation in filling optimization and deformation of wax pattern.

Abstract: The lost foam casting process of gray cast iron linner was simulated in this paper by using the numerical simulation method to study the properties of the filling and solidification for lost foam casting. And the comparison of the simulated results with the practical casting obtained from foundry was implemented. The results show that the reasonable technical parameters were obtained: pouring temperature of 1400°C, foam density of 13 kg/m³, vacuum of 0.04MPa, coating thickness of 0.5 mm and coating permeability of 9.5×10^-9m²/Pa·s.

Abstract: IRN (injection-rolling nozzle) is the key component of the new Polymer CIDR (Continue Injection Direct Rolling) process, and it has higher requirements than the metal roll-casting nozzle. In order to achieve uniform exit velocity, a new type of structure of the flow channel which is called IRN flow channel structure is designed by combining with the two traditional flow channel characteristics, i.e. the fishtail and coat-hanger flow channel. Then numerical simulation was used to calculate the fluid field in IRN flow channel and analyze 3D flow phenomenon and characteristics. The simulation results show that it has a uniform exit velocity of the IRN flow channel with the value of about 0.06m/s.

Abstract: A methodology of the establishment of a jet milling process visualizion simulation system is proposed. A specific analysis method of jet milling process is built with the LS-DYNA system featured ANSYS software.It has been put forward that the rate loss of part particles could be replaced by the rate loss of the whole particle flow in proportion and the result is proved through experiments.3DS Max software was used to build the visualize system. The caculation applicability and the error range of the simulation system for different kinds of particle are concluded by comparing the simulation results and the actual grinding results.

Abstract: Currently, finite element analyses are usually done by means of commercial software tools. Accuracy of analysis and computational time are two important factors in efficiency of these tools. This paper studies the effective parameters in computational time and accuracy of finite element analyses performed by ANSYS and provides the guidelines for the users of this software whenever they us this software for study on deformation of orthopedic bone plates or study on similar cases. It is not a fundamental scientific study and only shares the findings of the authors about structural analysis by means of ANSYS workbench. It gives an idea to the readers about improving the performance of the software and avoiding the traps. The solutions provided in this paper are not the only possible solutions of the problems and in similar cases there are other solutions which are not given in this paper. The parameters of solution method, material model, geometric model, mesh configuration, number of the analysis steps, program controlled parameters and computer settings are discussed through thoroughly in this paper.