Papers by Author: Meng Han Wang

Abstract: In this study, the finite element method (FEM) was used to simulate the rotary forging process of a heavy and thick-walled container head, and the problems about load, strain distribution and optimization of rotary forging method were studied. First, five controlling factors of load were defined, which were single reduction amount (δ), reduction rate (ν), thickness of top die (ω), rotary angle (θ) and rotary way (γ) respectively, and their influence degree on load was studied later. Then the influence of γ on strain distribution was investigated. The results indicate δ, ν and ω have a strong influence on load, while θ and γ have a small influence on it; the strain distribution under crossed rotary way which is proposed in this paper is more homogeneous than stepwise rotary way. Based on the research results, a new multi-stage rotary forging method was proposed, by which load and strain distribution could be controlled effectively by means of an optimized combination of the five controlling factors in different forming stages. The simulation results are in good agreement with practical production. This study can provide valuable guidance in load control and process optimization for other similar heavy blind-hole forgings. Keywords: Heavy and thick-walled container head, FEM, Rotary forging method, Load control, Strain distribution

Abstract: In order to reveal the forming laws，eliminate the forming defects appearing in the typical aluminum alloy web-rib parts，two types of preforms have been used in the final forging with numerical simulation software.Based on the simulation，the comparisons of metal flow，effective strain distribution are obtained between the two types of preforms applied in the final forging process，the forming laws of a symmetrical rib-web component have been obtained ,and the forming mechanism of defects often happened in web- rib parts also has been analyzed,the relationship between the fillet radius and metal flow velocity/ final load was obtain. The results show that the fiber breaking,vortex could be avoided，a high forming quality of rib-web part could be gained by the method of using the thin web-high rib preform in finish-forging.

Abstract: In the present study, an axis-symmetric electro-thermo-mechanical model has been developed to analyze a deformation process by continuous resistance heating. To obtain the transient temperature field prior to forming, a novel temperature-dependent model of the contact resistance was developed in the thermal-electrical analysis. The influences of the contact resistance, the current intensity and the die geometry on the temperature distribution were investigated. In the subsequent electro-thermo-mechanical analysis of the forming process by continuous resistance heating, the variations of the billet temperature distribution, forming force were obtained. The simulation results correspond well with experimental measured values. Furthermore, the influence of a current increasing during forming on the billet temperature and forming force was predicted in order to optimize the forming technology by continuous resistance heating.

Abstract: The aluminum tube with rectangle section can be produced by two-pass drawing process including non-plug and with-plug drawing. It is an effective method to study the deforming mechanisms by simulation, based on which the section varying of two-pass drawing got schemed and the relevant dies with reasonable dimensions got designed. The dynamics model and elasto-plastic FE model of the non-plug and with-plug drawing were established based on FEM software, then the simulation was performed. The sizing section of drawing die got optimized with angle β=178°, which eliminated instability. The influence of different semi-die angle 2 a on drawing load was researched, and a proper value of 2 a and 1 a was found. The touch boundary and touch-stress distribution of transitional drawing were achieved. Furthermore the residual stress and spring-back strain distribution after final drawing were achieved, which contributes to modifying the dimensions of rectangle sizing section.