Applied Mechanics and Materials Vols. 217-219

Abstract: Nickel-base superalloy 718 is a new kind of materials that is difficult to drilling. In this paper, the superfine deep-hole (ø36×5440mm)drilling test is based on the material. This paper analyzes the causes and laws of the tool wear , tool breakage ,and the hole axis deflection from the blade material, tool geometry parameters, cutting parameters and drilling methods.

Abstract: Rotary meat grinders with bone chip removal facilities are advanced meat mincing machinery, characterized by undesirable hard-particle separation from ground meat during grinding operations. The grinder plate with an involute spiral groove to facilitate removal of hard particles is developed. The perforated plate with bone chips removal facilities has a unique design including catcher groove, bone-collection chamber and bone-removal passage. Its 3D modeling in Pro/E software, machining process planning, milling path optimization, simulation based on MasterCAM and compiling post program were introduced and verified. The results indicated that adoption of CAD/CAM offers firms the potential to pursue new innovative strategies.

Abstract: The Al-Zn-Mg-Cu (7A04) alloys were prepared by using the method of spraying forming and the hot extrusion. The changes of microstructure and mechanical properties of the spray deposited Al-Zn-Mg-Cu alloy underwent ageing, regression and reageing treatment (RRA) was studied by scanning electron microscopy, X-ray diffraction and other methods. The results show that the tensile strength of the alloy aged at 120°C for 24 hours can reach the peak value (760MPa), but the elongation is only 4.8 percent. The toughness of the alloy regression treated at 160°C for 2 hours can increase to 9.0 percent, but its tensile strength decreases greatly (680MPa). The reaging treatment at 120°C can make the tensile strength up to 740MPa, while the elongation which is 8.2 percent still keeps a higher level.

Abstract: The crankshaft fillet rolling process is one of the commonly adopted methods in engineering to improve fatigue life of the crankshaft. The crankshaft fillet rolling process was simulated based on the explicit dynamic calculation in this paper. After the data acquisition program was compiled, the distribution of the crankshaft surface stress could be obtained. Coupling calculation between the operating stress at different bending moments and the rolling residual stress was based on the Smith-Watson-Topper (SWT) modle. After the simulation on the crankshaft fillet rolling process was carried out, which was based on optimization rolling parameters, the crankshaft fatigue strength was improved by 8.6%.

Abstract: This paper introduces the dynamic process of droplet transfer of DCEN MAG welding applied outside longitudinal magnetic field, and analyses the influence law of magnetic parameters on welding arc, droplet transfer behaviour, wire melting coefficient and weld formation. The feasibility of application of longitudinal magnetic field to DCEN MAG welding is established. We compared DCEN MAG welding with DCEP in order to further perfect rotating MAG welding.

Abstract: An X-ray inspection machine image detection system is designed by making use of the software Visual C++ 6.0, in which a lot of noise in the X-ray image are filted out by using corrosion algorithms and median filtering method. A analysis software of the bridging of the solderjoints, weld situation is designed,which can real-time display and zoom the image of solder joint inspection, and can alarm.

Abstract: The Al-Zn-Mg-Cu (7A04) alloys were prepared by using the method of spraying deposition and the hot extrusion. The effects of two-stage solid solution treatment and single solid solution treatment on the microstructure and mechanical properties of spray deposited 7A04 alloy were investigated. The microstructure and mechanical properties were observed and tested by optical microscopy, SEM, X-ray diffraction and other methods. It is indicated that the two-stage solid solution treatment is better than the single. After the two-stage solid solution, the sizes of recrystallization grains were small and a lot of precipitations were dissolved. And the microstructure was nice by ageing treatment. The tensile strength and elongation of the alloy can respectively reach 740MPa and 5.8 percent by the two-stage solid solution (at 450°C for 1 hour and 475°C for 2 hours) and the aging treatment.

Abstract: Metal-bonded cBN wheels with regular pores were fabricated using Cu-Sn-Ti alloy, cBN abrasive grains and alumina (Al2O3) bubble particles. Dressing experiments were carried out through rotary dressing method. Subsequently, grinding experiments were conducted on nickel-based superalloy GH4169. Comparative grinding performance was evaluated with vitrified cBN wheels in terms of grinding force and specific grinding energy. The results reveal that the pores in the working layer of the cBN wheels are exposed after rotary dressing. Compared to vitrified cBN wheels, grinding forces and specific grinding energy of the newly developed cBN wheels with regular pores are smaller.

Abstract: Abstract According to the high frequency vibration of the diamond tool and feed motion of the machine tool, the kinematic model of ultrasonic vibration machining was established by superposition principle. Its motion law was analyzed in theory. The experiments on the drilling force, the impact of load on the processing efficiency, and the surface quality of the workpiece with ultrasonic vibration drilling and traditional machining were carried out on the improved ultrasonic vibration drilling machine by way of drilling the ceramic material.

Abstract: Based on the orthogonal experiment, this paper studied the influences of depth of cut ap, table speed vw and grinding method gm on the two-side direction burr in grinding-hardening machine. The results show that, with thermal-force coupling effect induced in the grinding-hardening machine, the metal in the workpiece’s surface flowed to two-side direction of the workpiece that without any constraint and leaded to the burr’s formation. The depth of cut ap and grinding method gm are significant factors that affected the size of two-side direction burr, and the significant order are as follows: depth of cut a_p> grinding method gm > table speed v_w >interaction av. With the increasing of depth of cut ap or the grinding trip, the max size of the two-side direction burr increased gradually; and with the raising of table speed v_w, the max size decreased firstly and then increased. In actual application, it should adopted the grinding parameters a_p＝0.2mm，v_w＝0.6m/min and up-down grinding to improve the quality of grinding-hardening and reduce the size of the burr.