Advanced Materials Research Vols. 690-693

Abstract: A brief overview is given in the conventional domed bursting disc structure and manufacturing method. 316L stainless steel as a template is selected. With the investigation on bursting disc material tensile test method, the test results are summarized,also the burst results of disc burst pressure in different sizes. With the help of bursting disc material performance test and bursting disc burst pressure test of 316L , the test results provide a reference for other types of bursting disc.

Abstract: The warm tension-rotation bending process of AZ31 Mg alloy profile was simulated. The distribution of stress and equivalent plastic strain of the profile during the bending process were analyzed. The results indicate that tangential stress of cross-section of profile from the inside to outside after bending is shown as "tensile-compression-tensile-compression", which is appeared as "N"-shaped. Equivalent plastic strain of the outside of profile is maximum, which is 0.132; the inside of profile is lower, which is 0.069; the middle of profile is minimum, which is 0.003.

Abstract: Spline shaft is widely used as one of the important parts in machinery. Cold rolling process is currently the main processing method to small module splines.For the spline with position requirements, that is: one of the spline tooth is located at an angle of the spline shaft cross section, cold rolling processing can't guarantee the spline tooth position. The paper analyzes the defects existed in the rolling and processing of this kind of spline. Through transforming a hydraulic press and design special frock clamp to ensure the spline tooth position angle, the small modulus involute spline processing with position requirements is realized in the way of punch press processing.

Abstract: AP1000 steam generator of nuclear power is an important equipment in the PWR nuclear power plant and the structure of its bi-straight tapered cylinder forging is complex, which increases forming difficultly. In this paper, forming process of bi-straight tapered cylinder forging is determinated by numerical simulation and physical experiment. Influence law of dimension parameters of blank and auxiliary of forging forming quality is studied by numerical simulation. The lead specimen forming physical experiment of ratio of 1:15 validates the feasibility of bi-straight tapered cylinder forging forming process and finds that the results of numerical simulation are agreed well with the physical experiment.

Abstract: Aiming at the axle material 30CrMoA high speed cylindrical grinding force calculation problems, a consideration of plowing force grinding force model is established based on the Werner’s theory model of grinding force, and the friction force and plowing force coefficient is defined as variable parameters. On the basis of the finite element analysis software DEFORM-3D, a high speed cylindrical grinding simulation model method is presented.Through the theoretical value and simulation value contrast, a mutual authentication of grinding force model is proposed. According to the simulation analysis results of grinding force and grinding wheel speed, grinding depth and the relationship between the workpiece speed, theoretical and technical guidance for the grinding force calculation and the selection of grinding process parameters are provided.

Abstract: In the present study, an attempt has been made to experimentally investigate the effects of the cutting parameters on cutting forces in hard milling of AISI H13 steel with coated carbide tools. Designed based on Taguchi method, four factor (cutting speed, feed, radial depth of cut and axial depth of cut) four level orthogonal experiments were conducted. Three components of cutting forces were measured during hard milling experiments and then variance analysis was performed. Finally, the linear regression model was established.

Abstract: This paper aims at discussing chatter characteristics performed by a one-dimensional milling system having positive process stiffness and negative process stiffness. In this study, a dynamic model of the milling system is established first. An analytical form showing the critical chatter conditions including axial depth of cut, chatter frequency, critical spindle speed, etc. is formed. The analysis of process function shows that positive process stiffness occurs under most cutting conditions. However, process stiffness becomes negative when a one-dimensional milling system carries out low radial depth of cut in the direction of the feed (down milling) or semi-groove milling in the direction against the feed (up milling). Further analysis is made to explore chatter characteristics performed by the milling systems with positive process stiffness and negative process stiffness respectively. Finally, the prediction equation calculating critical chatter conditions of these two types of milling system, the range of rotation speed with high cutting stability and the range of rotation speed with low cutting stability is proposed.

Abstract: The influence of chip formation technology on the simulation of machining unidirectional fiber reinforced polymer composite (FRP) is investigated. Two-dimensional macro-mechanical FE model was developed for orthogonal machining. Tsai-Hill failure criterion was implemented in VUMAT Abaqus subroutine. Two different chip formation technologies were simulated, analyzed and compared with experiment in literature. The results show that chip formation technology makes a difference in FRP machining simulation for various cutting conditions. Though chip shape, cutting forces and sub surface damages predicted by ALE model are more reasonable than that by element deletion model, predictions in both models are not satisfactory due to inherent limitations associated with the macro mechanical FE model and Tsai-Hill damage criterion.

Abstract: A mechanistic approach for the prediction of end milling including tool wear is proposed in this paper. The additional cutting force caused by increase of flank wear is considered. Total cutting force is regarded as the summation of the rake-face force and flank-face force. Cutting force coefficients are identified by the cutting tests of various cutting parameters combination on 300M steel. Then the cutting force coefficients models are established based on the cutting parameters. The prediction of cutting force obtained by numerical method is validated by the cutting experiments.

Abstract: Dry machining was conducted on Ti-6Al-4V alloy with three different types of microstructure: globular, bi-modal and fully lamellar microstructures. The effects of cutting speed on the cutting force and chip formation were investigated. The differences in cutting force and chip morphology are found only at cutting speed lower than 100m/min. The main cutting force and chip thickness when machining Ti-6Al-4V alloy with globular microstructure are lower than these when cutting Ti-6Al-4V alloy with bi-modal and fully lamellar microstructures at cutting speed lower than 100m/min. The tendency of segmented chip formation is the highest for cutting Ti-6Al-4V alloy with fully lamellar microstructure and the lowest for machining Ti-6Al-4V alloy with bi-modal microstructure at cutting speed lower than 100m/min because of their differences in increase of shear strength with strain rate.