Advanced Materials Research Vols. 129-131

Abstract: In order to improve the effects of rare earths (RE) as microalloy on the recrystallization behavior in the high strength micro-alloyed steel, the X80 pipeline steels with different RE content were produced with a vacuum induction furnace, a series of hot torsion tests were performed under a range of deformation conditions, and the stress-strain curves were analyzed. The results showed that trace RE would improve the austenite recrystallization behavior. The activation energy of deformation and static recrystallization of the austenite in the X80 pipeline steel without RE additions were respectively 393 and 366 kJ/mol. When the RE addition was 0.0025 wt.%, the activation energy of deformation and static recrystallization were reduced by 33 and 29 kJ/mol respectively. But when the RE addition was increased to 0.0220 wt.%, RE would significantly inhibit the dynamic recrystallization of the austenite, the activation energy of deformation would be increased by 35 kJ/mol, but the activation energy of static recrystallization would reduce by 15 kJ/mol.

Abstract: Flange connections in petrochemical equipments easily leak high temperature gas or fluid. Configuration of flange with preloaded diskspring technique are introduced to solve this problem. However, the preloaded diskspring as an important role in flange is easily corroded at high temperature. Temperature fluctuation and strong corrosive circumstances would lower strength of diskspring and causes stress relaxation. Therefore, it is important to search suitable material for diskspring without reduction of strength and stress relaxation used in medium temperature range and strong corrosive circumstances. In this paper, precipitation hardening stainless steel 0Cr17Ni7Al (17-7PH) was studied systematically. Medium temperature mechanical properties are tested experimentally by electric stretch mechanical experiment setup with heater. The medium temperature elastic modulus variations are measured. The variation of elastic hysteresis curve loop area with reciprocating load-unload is measured at different temperature. Experimental results show that the elastic modulus of this material decreases only 0.1% from room temperature to 350°C. The elastic modulus remain almost unchanged at temperature below 300°C which ensure that the loading stability of diskspring does not change when temperature is changed under 300°C. It was found that the elastic hysteretic loop area can be minimized by five times loading-unloading at 300°C which ensure to decrease diskspring’s stress relaxation during long time use within medium temperature range, and it is a key basis for this type of diskspring making. Conclusion: 17-7PH is an ideal elastic material for diskspring used in medium temperature range and highly corrosion environment, and diskspring should be prestressing treated five times at 300°Cduring manufacture to decrease stress relaxation.

Abstract: Environmental pollution is a serious issue for human being. In the present study, we propose a C-Fe3O4 composite magnetic nanoparticles for the adsorption of dye pollutants. Since carbon shows high affinity for dye molecules and Fe3O4 shows benign response to a magnet, the material is suitable for remediation of environmental pollution in a convenient way. The material was prepared and was characterized by scanning electron microscopy, nitrogen sorption and powder X-ray diffraction. As a model dye, methyl red was used to evaluate the adsorption performance of the nanocomposite. The result demonstrates that the composite material can adsorb methyl red efficiently and it can be easily recovered by an external magnet, which simply the operational process in comparison with traditional centrifugation or filtration. It is a promising material for environmental remediation.

Abstract: In a lot of factors, thermal deformation of motorized high-speed spindle is a key factor affecting the manufacturing accuracy of machine tool. In order to reduce the thermal errors, the reasons and influence factors are analyzed. A thermal error model, that considers the effect of thermodynamics and speed on the thermal deformation, is proposed by using genetic algorithm-based radial basis function neural network. The improved neural network has been trained and tested, then a thermal error compensation system based on this model is established to compensate thermal deformation. The experiment results show that there is a 79% decrease in motorized spindle errors and this model has high accuracy.

Abstract: The present study focuses on preparation of ENR-50/PEMA-NH4CF3SO3 proton conducting polymer electrolytes by solution casting technique. Conductivity increases with NH4CF3SO3 concentration up to 40 wt.% but decreases with further increase in salt content. The temperature dependent conductivity study shows that the conductivity-temperature behaviour of ENR-50/PEMA-NH4CF3SO3 electrolytes follows the VTF rule. DSC studies show that the Tg increases with increase in salt content. This means that the increase in conductivity of ENR-50/PEMA-NH4CF3SO3 is incorrelated to the increase of the segmental motion of the host polymer chains but may be attributed to the increase in the concentration and migration rate of charge carriers.

Abstract: In order to obtain the optimal scheduling plan which includes the reasonable task start time and resource allocation for complex product design project, a multi-mode resource-constrained scheduling method for complex product design tasks was proposed. In the method, human resource was separated out from the technology resource aiming at characteristics of product design process. The mathematics model was built based on the idea of multi-mode resource-constrained scheduling problem. To solve the model, designer-task-resource matching degree matrix was calculated and genetic algorithm was used. Finally, a case study was presented to validate the method.

Abstract: Effects of glue spread, adhesive kind and curing agent ratio on bonding quality of wood-FRP (Fiber Reinforced Plastic) interface were investigated to choose the optimal adhesive and condition of bonding wood-FRP composites. Two different kinds of epoxy resin and one kind of curing agent were used to bond wood-wood and wood-FRP samples with three different glue spread. Shear strength of samples were measured by compression shear test. The results indicated that bonding strength of wood-FRP sample with glue spread of 300 g/mm2 and curing agent ratio of 40% were the best, when using the same epoxy resin and curing agent. The shear strengths of wood-FRP samples were less than those of samples without FRP. The bonding qualities of samples with E-44 epoxy resin/T-31 curing agent system were better than those of E-51 epoxy resin/T-31 curing agent system.

Abstract: Laminated Veneer Lumber (LVL) panels made from birch (Betula platyphylla Suk.) veneers were tested for physical and mechanical strength properties in this study. The static bending test were conducted on the LVL, and bending test and shear test were conducted on veneer and three-lamination LVL. The effects of the relative humidity on the modulus of elasticity (MOE) and bending strength (MOR) of birch LVL with vertical load and parallel load were investigated. There were four relative humidities including 40%, 50%, 60% and 70%. The results showed that the MOE and MOR of LVL would diminished with the increase of relative humidity, the bending strength of veneer sample decreased as the relative humidity increased, and there was noticeable effect of relative humidity on shear strength of PF resin.

Abstract: In this paper, the chemical character of NiP substrate of computer disk is analyzed, the CMP kinetics processing is discussed to indicate that the chemical reaction is the slowest and the control process. By analyzing essentiality of slurry on NiP film CMP, it is indicated that the chemical component of slurry acts the important role in CMP. New type of alkali slurry for NiP substrate was prepared and its CMP mechanism is studied with alkali slurry. Strong complexation of complex agent improved selectivity of concave area and convex area to get higher removal rate. Low roughness is realized with small size and low hardness silica sol as abrasive.

Abstract: Three different nondestructive testing (NDT) methods and the static bending test were conducted on the Laminated Veneer Lumber (LVL) made from birch (Betula platyphylla Suk.) rotary-cut veneers in this study. The NDT methods included the longitudinal vibration method, in-plane and out-plane flexural vibration method. The linear regression between dynamically elastic module and bending strength (MOR) and the effects of relative humidity on the reliability of NDT methods for LVL were investigated. There were four relative humidities including 40%, 50%, 60% and 70%. The results showed that the three non-destructive testing methods can be applied to test mechanical properties of birch LVL, the theory MOR result obtained by adjusted regression equation were reliable and can be applied in the actual project.