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Zhang M.,Shanghai University | Wan Z.,Shanghai Huizhong Automotive Manufacturing Co. | Li L.,Shanghai University
Materials Today: Proceedings | Year: 2015

Continuous cooling transformation characteristics of steel 22MnB5 were studied in detail using dilatometer method. The influence of hot forming procedure parameters, such as heating rate, austenizing temperature, and holding time on microstructure transition was analyzed. Microhardness was tested afterwards. The microstructure obtained from the dilatometer samples reveals that for heating temperatures above 850°C samples fast heated for 10s holding couples with full austenite transformation and can get a fully martensitic microstructure after immediately quenching with 30°C/s cooling rate. The same is for samples heated with 10°C /s to 930, 900, 880, 860, and 840°C for 300s holding conditions. In the studied cases, hardness of the samples is around 500HV. Hot stamping V-type automotive parts were subsequently manufactured using a self-designed special tool set with cooling system in it, heating to 860, 880, 900, and 920°C for 300s holding correspondingly, following die quenching as soon as possible. The tensile strength of the parts reaches 1500MPa, and total elongation A80 achieves 8%. It is found that heating temperature lower to 880°C is good for getting a much finer fully martensitic microstructure, and a better property combination. © 2015 The Authors.

Lang L.,Beihang University | Zhang F.,Beihang University | Cheng P.,Beihang University | Wang T.,Shanghai Huizhong Automotive Manufacturing Co.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014

The multi-step hydroforming process of trailing arm which is one of the typical automotive chassis parts was optimized by numerical simulation and experiments. In order to improve forming efficiency and quality consistency, a multi-cavity mould was used and the influences of tool lay-out on hydroforming process were studied. It is a reasonable tool lay-out that hydroforming tool has symmetrical distribution with two “C” shapes compared to other ones. It can improve the stress condition of the tool and parts during hydroforming process and make the quality of the forming parts be guaranteed, as well as enhance the production efficiency. ©, 2014, Zhongguo Jixie Gongcheng/China Mechanical Engineering. All right reserved.

Wenbin Z.,Shanghai Key Laboratory of Modem Metallurgy and Materials Processing | Wenbin Z.,Shanghai Huizhong Automotive Manufacturing Co. | Hongbo Z.,Shanghai Key Laboratory of Modem Metallurgy and Materials Processing | Dengke Z.,Shanghai Key Laboratory of Modem Metallurgy and Materials Processing | And 4 more authors.
China Foundry | Year: 2011

The effect of niobium on the formation of NbC phase and solidification structure in high carbon equivalent grey cast iron was investigated. The experimental results indicated that an increase in the niobium content is favorable to refining the graphite and eutectic cell; and the pearlite lamellar spacing is reduced. Based on the thermodynamic calculation the formation of NbC is prior to the eutectic reaction. The reduction in the pearlite lamellar spacing is mainly attributed to the decrease of eutectic temperature with the addition of niobium. Additionally, properties including hardness and wear resistance were improved after the addition of niobium.

Shen Y.-F.,University of Shanghai for Science and Technology | Shen Y.-F.,Shanghai Dianji University | Zheng S.-L.,University of Shanghai for Science and Technology | Wang Z.-R.,Shanghai Huizhong Automotive Manufacturing Co.
Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao | Year: 2015

A program load spectrum compiling method for automotive components was introduced with swing arm as example. Based on low loading strengthening property, a spectrum compiling method considering the strengthening effective loads is put forward, which overcomes the deficiency of the traditional methods, in which only the damage effect of low amplitude loads is considered. By transferring the strengthening loads to the most effective level, the bench tests show that the total cycling blocks decline sharply under homemade specification. It proves that while deleting the useless loads during the spectrum compiling process, the strengthening loads' influence should be taken into account. Moreover, the real service condition of automotive parts by simulation can be faster and more real, and it is significant to predicate the failure mode of durability tests and to estimate service life of automotive parts more accurately. © 2015, Chinese Mechanical Engineering Society. All right reserved.

Fang M.,Tongji University | Tan J.,Shanghai Huizhong Automotive Manufacturing Co. | Xu G.,Shanghai Huizhong Automotive Manufacturing Co.
Qiche Gongcheng/Automotive Engineering | Year: 2013

A method by combining test and finite element analysis, with maximum strain energy density as parameter to predict the fatigue life of vehicle rubber bushings is proposed in this paper. Firstly a vehicle stochastic nonlinear dynamic model is set up using dynamic substructure technique. Then Monte Carlo method is used to simulate the random excitations of road surface and engine, and the displacement, velocity and acceleration responses of rubber bushings in vehicle under those excitations are obtained. Finally with these response characteristics as excitations to the FE model for rubber bushing, the maximum strain energy density is obtained, by which the fatigue life of rubber bushings under random load excitation is predicted with fatigue life prediction model. The results of verification by the fatigue test on front engine cradle show that the method proposed has reasonable accuracy in predicting the random fatigue life of vehicle rubber bushings.

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