Advanced Materials Research Vols. 1004-1005

Abstract: the process of the wheel style grinding wheel grind concave surface of rotors has been simulated in this paper,through changing of the location of grinding point, the qualitative change of the strain and stress has been simulated and analyzed, obtaining that when the grinding point is at the midpoint of wheel grinding arc, the strain and stress of grinding wheel are the smallest, when at other locations, strain presents parabolic and spreads to the edge, the maximum and minimum stress are in the process of gradually decreasing as grinding dot moving from the edge to the halfway point , and the maximum stress and strain are occurred in a neighborhood of the grinding point.

Abstract: During the traditional cutting processing, cutting tool and the workpiece contact each other continuously along with the chip removal, this paper puts forward a kind of vibration cutting structure based on the parallel mechanism known as 2R-2P, in which certain elliptical trajectory could be taken, according to the principle of applying separate characteristic between vibrating cutting tool and workpiece to lower cutting force, cutting temperature, so as to improve the machining accuracy. Firstly, illustration in the mechanism of formating the surface morphology in elliptical vibration cutting and the micro trajectory of tip is carried out, secondly, completing the structure design and kinematics analysis, the tip vibration curve has been attained. Finally, through the statics and dynamics analysis, distribution rule of stress and strain is concluded when the structure is subjected to external force changing periodically, as the vibration mode and the harmonious response, verifying the feasibility of the structure and the ability of tip vibrating in ellipse trajectory.

Abstract: In order to improve the accuracy of rolling force parameters,the elastic deformation and pressure between rolls of tandem cold rolling are calculated using divided element method in this paper. Bland-Ford model is used to calculate the rolling force, and the lengths of flattening contact arcs of each element are calculated. Considering the flattening contact arc lengths and tensile stress synthetically, rolling force parameters are calculated iteratively. Then the corresponding procedure is developed, and the distribution of rolling force, pressure between rolls and tensile stress are calculated with this procedure. The results are basically consistent with the measured data, and it will be useful to thermal crown calculation and strip flatness control.

Abstract: Recently, wear and corrosion of the engine parts surrounded with combustion chamber is more serious compared to the other parts of the engine due to using of heavy oil of low quality. Therefore, an optimum repair welding for these parts is very important to prolong their lifetime in a economical point of view. In this study, Inconel 625 filler metal was welded with GTAW method in the forged steel which would be generally used with piston crown material. In this case, the mechanical and corrosion properties between weld metal zone (WM) welded to the groove which were artificially made in the base metal and deposited metal zone (DM) only welded by Inconel 625 filler metal on the surface of the base metal were investigated using electrochemical methods, such as measurement of corrosion potential, anodic polarization curves, cyclic voltammogram and impedance etc. in 35% H₂SO₄ solution. The deposited metal zone exhibited a better corrosion resistance compared to the weld metal zone, furthermore, its corrosion potential was a nobler value rather than that of the weld metal zone. However, the hardness indicated more or less higher value in the weld metal zone. The corrosive products after measurement of anodic polarization curves was hardly observed both in the weld and deposited zones, while, the morphologies of the corroded surfaces exhibited general and pitting corrosion in the weld and deposited metal zones respectively. The fine pearlite microstructure was a little observed in the weld metal zone, moreover, the microstructure of ferrite with elliptical pattern was significantly increased in the deposited metal zone. As a result, it is considered that the amount of Cr, Mo and Ni having a high corrosion resistance diffuse and migrate from the weld metal zone to the base metal zone, thus, the deposited metal zone indicated a better corrosion resistance than the weld metal zone because the amount of Cr, Mo and Ni were much involved in deposited metal zone compared to the weld metal zone.

Abstract: Isothermal compression experiment of Al-W alloy was carried out using Gleeble1500 thermodynamic simulator within a temperature range of 420°C-570°C and a strain rate range of 0.001s^-1-1s^-1。And the constitutive relationship model for this alloy was successfully developed using BP neural network. In the proposed model, the input variables are strain, strain rate and deformation temperature while the flow stress is the output variable. The results show that absolute maximum error between predicted and experimental values of flow stress is less than 10.0Mpa, the correlation coefficient is 0.993. It was found that the established constitutive relationship model could provide a good representation of the test data and describe the whole deforming process better compared with the traditional method.

Abstract: Aiming at the serious crack phenomenon of automobile rim butt welding in a domestic wheel plant, means of analysis such as chemical analysis, tensile test, bending test, macrocosmic and microcosmic examination were used to find out the formation mechanism. Results showed that the chemical compositions and mechanical properties of base metal near the weld fracture meet the quality requirements, while the widmanstaten structure and composite oxide inclusion covered in unmelted region, which could cause micro-cracks in the welded seam and lower the plasticity of welding seam, were the key reasons to cause cracks of welding.

Abstract: Removed due to intellectual right issues.

Abstract: The determination of EG content in the liquid products of PET hydrolysis process under microwave irradiation at 170°C 180°C and 190°C was measured by Gas chromatography. The chromatographic column was quartz capillary chromatographic column the carrier gas was nitrogen hydrogen flame ionization detector FID. The result indicated that the concentration curves of EG didn’t follow a dynamic process which suggested that PET hydrolysis under microwave was not a continuous process dynamics.

Abstract: The role of pores structure in porous titanium with helical pores was studied. The results showed that porosity of porous titanium depends on diameter of titanium fiber (d₁), screw diameter (d₂) and screw pitch (d₃). With the increase of titanium fiber diameter, the decrease of screw diameter and screw pitch, the porosity of porous titanium decreases. Compressive yield strength and Young’s modulus increase with the decrease of porosity, and the final functional expression of compressive yield strength and Young’s modulus depending on porosity was given.

Abstract: In order to study the influence of process parameters on forming quality of printer board with metal-insert,shorten the development cycle,reduce the enterprise cost,the warp trend and reasons of injection process parameters,including packing time,hold pressure,mold temperature,melt temperature,on the warpage of the part were analyzed by means of software moldflow. The results show that warpage amounts decreases with packing time and hold pressure increasing,larger packing time and longer hold pressure is advantageous to the injection parts molding;And warpage amounts increases with mold temperature and melt temperature increasing,the lower mold temperature and melt temperature is advantageous to the injection parts molding;Among the four parameters,the melt temperature had the greatest influence,followed by the mold temperature and the hold pressure,packing time had the minimal influence on the warpage.