Advanced Materials Research Vols. 189-193

Abstract: This paper mainly looks at the research on cold extrusion process and die of vehicle gear sleeve with spline, optimized the cold extrusion process of the part using FEM analysis, which gives us a theoretical basis for further exploration on the cold extrusion, and selecting optimum process parameters. The optimized results were verified by experiments and mass production. It analyzes the effect of the punch shape of gear container to metal flowing. The plastic flow could be controlled by the selection of the punch shape of gear container which reduced the resistance to deformation, and the gear profile was full without folding defects.

Abstract: The paper deals with the influence of severe plastic deformation on the typical powder metallurgy (PM) microstructural characteristics, such as porosity, of a PM aluminum alloy. A commercial ready-to-press aluminum based powder was used as material to be investigated. After applying different compacting pressures (400, 500, 600 and 700 MPa), specimens were debinded in a ventilated furnace at 400 °C for 60 min. Sintering was carried out in a vacuum furnace at 610 °C for 30 min. The specimens were ECAPed for 1 pass. The dimensional and morphological porosity of investigated materials were measured individually for each pore. Results show that ECAP generates shearing stress breaking down the oxide film; this, coupled to particles deformation under local constraints, enables strong bonding and stability. Therefore, ECAP supports next progressive decreasing of pore size as well as strongly influences both dimensional and morphological porosity characteristics, considering that small pores evolve easily to a circular form. Moreover, ECAP cause strong bonding between adjacent particles, which results in a significant increase of mechanical properties.

Abstract: In order to make the spiral drum has a good performance and human-computer interaction function. This paper made the spiral drum module division base on the modularization theory and parametric design. Built the 3 D parametric model of spiral drum by Pro / E software, completed the assembly of spiral drum parts, and analyzed the interference of each component, consequently, improved the accuracy of the design. It also can made parametric driving for relative modular as user different needs for spiral drum design. namely, it can got the 3-D model and assembly drawing, and can achieve the goal of improving the drum design efficiency.

Abstract: Using the compression tests on a Gleeble-1500 thermo-mechanical simulator to study the dynamic recrystallization behaviours of AZ80 magnesium alloy in the temperature range of 593-683K and strain rate range of 0.01-10s^-1. By the analysis of the dynamic recrystallization kinetics, the Avrami exponent (m) and the constant (k) have been determined, and they aren’t constant and depend on the dimensionless parameter(Z/A).

Abstract: The thickness variation of drawing part is usually very complicated, which causes the accurate calculation of the surface area of drawing part to be very difficult. Blank optimization of sheet metal forming is often considered as a multi-objective problem. A blank optimization strategy of sheet metal forming process was suggested based on Response Surface Methodology (RSM). Latin Hypercube Sampling (LHS) method was introduced to design the rational experimental samples; the objective function was defined based on crack factor and wrinkle factor; the accurate response surface for sheet metal forming problem was built by Least Square Method; Genetic Algorithm (GA) was adopted in optimization and Pareto solution was selected. The strategy was applied in blank optimization of an auto-part, this method was proved suitable for blank optimization of sheet metal forming.

Abstract: At present the application layer in the network data transmission and expression of the most widely used protocol is Http protocol, embedded devices through the Internet network remote monitoring of data transmission direction to one of the main focus in the Web server for embedded systems. Embedded web server to achieve this, no operating system support, embedded system itself Common Gateway Interface, to complete web page publishing, the most important is the use of embedded devices that can be used as remote monitoring software system.The key equipment for the motor system for remote network monitoring, this paper describes the design of the specific structure of web servers and for system implementation and realization of the key technologies used to give a detailed exposition, in the end PC to run on the results of the test.

Abstract: With expendable pattern casting, WC infiltrated layer on carbon steel surface can be gained. Metallography of infiltrated layer was researched, hardness of infiltrated layer was tested and wear resistance was also tested on ML－100 attrition testing machine. Experimental results shoes that: microstructure of infiltrated layer is made up of pearlite, ferrite and WC particle, Brinell hardness of infiltrated layer is 1.7 times that of the matrix and wear resistance is 2.97 times that of the matrix.

Abstract: Bending process is an important process in the metal sheet forming in many industries. The main problem of the bending process is the spring-back phenomenon after removing the punch. This research aims the investigation on effect of residual stress on springback behavior of sheet metal in U bending process. The corner setting technique and bottoming process were designed for experiments. The corner setting technique and bottoming has reduced the thickness in bending area to 5, 10, 15 and 20 percent of the original sheet thickness. Clearance between punch and die of both processes was equal to same the thickness. The residual stress value and springback phenomenal were investigated by commercial program code DEFORM 2D which was able to analyze the effect stress and force in bending area. Electrolytic zinc coated carbon steel grade JIS; SECC, JIS; 440 and JIS; 590 which having the thickness of 1 mm were employed as the workpiece material for all experiments. The result of three materials in conventional U bending die shows larger spring back than the corner setting technique and bottoming process. Moreover, the corner setting technique reduces spring back value in bending process but requires high bending force. Corner setting technique and bottoming process at 15% and 20% shows that the spring go of all parts. The FEM simulation results explained the effect of residual stress to springback phenomenal. Comparisons between experimental and finite element method results were also performed.

Abstract: The solid solution of the second phase particle and austenite grain growth behavior of the high niobium-containing RE steel was studied by mathematical calculation and extraction replica technique. The purpose of the study was to investigate the effects of Rare Earth La on austenite grain growth and propose an empirical equation for predicting the austenite grain size of RE steel. Austenite grain grows in an exponential law with the increase of heating temperature, while approximately in a parabolic law with the increase of holding time. Results show that the RE steel has good anti-coarsening ability at elevated temperatures. When soaking temperature is lower than 1250°C , AGS and growth rate are small for high niobium steel, but soaking temperature is lower than 1220°C , AGS and growth rate are small for RE steel. RE La can promote solid solution of second-phase particles Nb(C, N), the solution temperature decrease 30°C than high niobium steel.

Abstract: With the constant development of numerical control technology, the development cycle and efficiency of CNC (computer numerical control) system is restricted with NC code compiler insufficient in Rapid Development and efficiency. In order to solve this problem, a compiler developed with Lex&Yacc for CNC system based on PC is put forward. This compiler is consisted of a lexical analysis module, a syntax analysis module and an object-storage module. With designed in modules, parameter-driven programming and assisted by Lex&Yacc which is an efficient language for compiler development, this compiler has great advantages such as high efficiency and short development cycle, which mean realistic significance to engineering application. The main principal and design process of every module was expatiated and at last a test of compiling a NC file was executed successfully, which verified the validity of this proposed method.