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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.

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.

Yue Z.-G.,CITIC Heavy Industries Co. | Gao X.-Y.,CITIC Heavy Industries Co.
Zhuzao/Foundry | Year: 2016

Shrinkage, dispersed shrinkage and crack of R zones easily occurred in head casting of mine mill causes during casting process. By reasonable designing of riser, pad, chills and pouring system, the defects above were avoided. The quality of head is good to meet the UT and MT requests. © 2016, Chinese Mechanical Engineering Society. All right reserved.

You M.,CITIC Heavy Industries Co. | Diao X.,CITIC Heavy Industries Co.
Advanced Materials Research | Year: 2012

Casting process of heavy section ductile iron wind generator rotor shaft was simulated by finite element software ProCAST. Gating systems was designed according to the structure of the casting. Solidification behavior of the casting was then analyzed. Defects, especially porosity, of the casting during solidification were predicted and hence casting process optimization has been performed based on the simulation results in order to avoid porosity in the casting. Results show that solidification time of the casting is more than 14h when cooled in sand mold. Porosity easily formed at the thermal center and in the middle of flange. Solidification time is evidently decreased with the help of chills. However, porosity tendency depends on the position of chills. A ductile iron rotor shaft casting with good quality was finally produced according to the simulation results. © (2012) Trans Tech Publications, Switzerland.

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.

Li R.,Xuchang University | Ding R.,Xuchang University | Wang F.,CITIC Heavy Industries Co.
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2011

A novel four phase translational meshing motor with double rotors is presented, and each magnetic pole of new motor consists of one stator, one internal and external rotors. Four internal rotors of magnetic poles are fixed together as one four-pole internal translational rotor and four internal rotors are fixed together as one four-pole external translational rotor. If controlling electromagnetic force of magnetic poles, the internal and external translational rotors move opposite direction synchronously by circle translation with the restricting of eccentric shafts mechanism, meanwhile, it drive internal ring gears meshing with external gears to output big torque with the elimination of inertia force and the increases of output torque. The prototype is found, and the flux linkage characteristic is calculated through finite element method. In additional, the static torque is computed utilizing the magnetic coenergy principle. The characteristics of speed and torque are acquired form prototype experimental results. Compared with the driving device of traditional motor and reducer, the double rotors translational meshing motor is a feasible translational motor with features of rapid start, high efficiency and big output torque. © 2011 Journal of Mechanical Engineering.

Zhao Y.,Xi'an Jiaotong University | Qin D.,Xi'an 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.

Chunlei G.,University of Science and Technology Beijing | Yongdong X.,CITIC Heavy Industries Co. | Mengjun W.,Central South University
Materials Science and Engineering A | Year: 2011

Isothermal compression tests were carried out on Al6061 using a Gleeble-1500 thermal simulator at temperatures ranging from 573 to 723K and strain rates from 0.5 to 30s-1. The flow stress of Al6061 was characterized based on an analysis of the true stress-true strain curves. A mathematical mode coupling flow stress with strain, strain rate and temperature for Al6061 has been proposed by using a hyperbolic sinusoidal type equation. The material constant α is 0.01MPa-1 in the model, whereas other material constants n, lnA and Q are found to be functions of strain. The predicted results from this proposed model are found to be in good agreement with the experimental flow stress curves which can be used to predict the required deformation forces in hot deformation processes. © 2011 Elsevier B.V.

Luoyang Mining Machinery Engineering Design And Research Institute Co. and CITIC Heavy Industries Co. | Date: 2013-02-28

The invention provides a system for calcining active lime, including a precalcining furnace for receiving limestone materials to be calcined and precalcining the limestone materials, and a rotary kiln for receiving the materials containing precalcined product from the precalcining furnace, outputting the formed active lime, and at the same time supplying a first flue gas to the precalcining furnace. The calcining system further includes a precalcining furnace combustion device, which generates a second flue gas and supplies it to the precalcining furnace, such that the limestone materials are precalcined in the precalcining furnace under the action of the first flue gas and the second flue gas. In this way, the precalcining rate of the limestone materials in the precalcining furnace is significantly improved. Since the heat exchange in the precalcining furnace is mainly in the form of convective heat exchange having a high heat efficiency, the heat exchange efficiency of the whole system is improved, and thus the heat consumption of the system is reduced.

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