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You M.,CITIC Heavy Industries Co.
Zhuzao/Foundry | Year: 2014

The wire feeding production process of ductile iron grinding table with a gross weight of 95 t was introduced. The microstructure and mechanical properties, ultrasonic and testing magnetic particle all meet the technical requirements of the casting. Meanwhile, mass production achieves with a steady quality up to now. The production practice shows that wire feeding process is an effective way to produce large ductile iron castings.

Li W.,Tsinghua University | Shen B.,CITIC Heavy Industries Co. | Shen H.,Tsinghua University | Liu B.,Tsinghua University
IOP Conference Series: Materials Science and Engineering | Year: 2012

The paper presents the recent progress made by the authors on modelling of macrosegregation in steel ingots. A two-phase macrosegregation model was developed that incorporates descriptions of heat transfer, melt convection, solute transport, and solid movement on the process scale with microscopic relations for grain nucleation and growth. The formation of pipe shrinkage at the ingot top is also taken into account in the model. Firstly, a recently proposed numerical benchmark test of macrosegregation was used to verify the model. Then, the model was applied to predict the macrosegregation in a benchmark industrial-scale steel ingot. The predictions were validated against experimental data from the literature. Furthermore, macrosegregation experiment of an industrial 53-t steel ingot was performed. The simulation results were compared with the measurements. It is indicated that the typical macrosegregation patterns encountered in steel ingots, including a positively segregated zone in the hot top and a negative segregation in the bottom part of the ingot, are well reproduced with the model. © Published under licence by IOP Publishing Ltd.

Fan B.,Henan University of Science and Technology | Fan B.,CITIC Heavy Industries Co. | Pu J.,Henan University of Science and Technology | Liu G.,Henan University of Science and Technology
International Review of Electrical Engineering | Year: 2013

A new method to direct power control (DPC) of the three-phase voltage source PWM rectifier base on the virtual flux is proposed in this paper, in which the formation mechanism of the switch table is analyzed. With the development of environment simulation model of the system based on Matlab / simulink, it is shown that the DPC system occupies good dynamic response so as to achieve active power and reactive power control, which ensures that the input side of the unity power factor control. The experimental results illustrate DPC system proposed in this paper can achieve higher power factor and lower harmonic disturbance (THD) than the conventional current control strategy. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.

Zhang X.-J.,Hohai University | Wang D.-G.,Hohai University | Lai X.-J.,CAS Nanjing Institute of Geography and Limnology | Song H.-H.,CITIC Heavy Industries Co.
Journal of Hydraulic Research | Year: 2016

A high-resolution typhoon-induced storm surge model based on the unstructured grid finite-volume method was developed for the Shanghai coast. The storm surge generated by Typhoon Prapiroon (2000) was simulated, and the results demonstrated good agreement with observations. The average relative error in the simulated water level was 12.8%. The statistical difference between the predicted and observed typhoon tracks was also analysed using data from 2004 to 2011. After Johnson transformation, the angular deviation follows a normal distribution. Five simulations were conducted for the observed track and four synthetic tracks (deviating 30° and 45° clockwise and counterclockwise from the observed track). The simulations reveal that the surge level is sensitive to the deviation angle. A new predictive scheme with optional angles deviating from the forecasted track was developed and applied to Typhoon Matsa (2005). The results indicate a significant reduction in the error of the peak water level. © 2015 International Association for Hydro-Environment Engineering and Research.

Zhao Y.,Xian Jiaotong University | Qin D.,Xian Jiaotong University | Wu W.,CITIC Heavy Industries Co.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2011

Multi-failure modes of each gear and multifactor relevance were existed in a planetary gear transmission. Based on the stress-strength interference theory, general reliability computation model for mechanical transmission system was presented under conditions of multi-failure modes and multifactor relevance, and applied to the reliability analysis for the multi-stage planetary transmission system used in shield machine cutter drive. Reliability models for each failure units like gears and bearings were established first. The reliability model of transmission system was obtained considering main failure modes and failure relevance of load and application factor, and Monte-Carlo method was used to simulate the result. The results demonstrate that the model can evaluate the reliability of shield machine cutter drive multi-stage planetary transmission system accurately.

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