The temperature and carbon content at blow end point should be controlled strictly during the BOF converter steelmaking process. Meanwhile many factors have impact on the temperature and carbon content at blow end point. These factors include initial weight of molten iron, initial weight of scrap steel, oxygen blow duration, the temperature and carbon content when lowering the sublance, as well as the weight of all kinds of addition reagents. In order to determine the optimized process parameters so as to reach the ideal temperature and carbon content at blow end point, this paper built a series of experiment programs based on DOE. According to the experiment programs, authors conducted these experiments with the help of RBF neural network and analyzed each parameters as well as some interactions impact on target. According to the statistical analysis results of experiment data (the SNR), authors extract significant factors and reached an optimized process parameters A3B3C2D1E1F3G2H3J2. According to the RBF neural network, the prediction error of carbon content and temperature is only 0.0063 and 0.0159 respectively. The result proves that DOE is an effective method in optimizing process parameters, and worth promoting and applying in converter steelmaking process.

For improving braking efficiency, the high friction composite brake shoe, instead of cast-iron shoe, is widely used in railway wagon. However, some flange and tread of the foundation brake rigging wear frequently in operation, leading to the over standard of wheel diameter difference, which affects the safety performance and the running efficiency of railway transport. This paper uses the normal pressure between wheels and shoes as the evaluation index of tread wear and the lateral shift of brake beam as the evaluation index of flange wear. With the multi-body dynamics simulation method, take a research on the influence of curve braking for flange and tread wear. Firstly, establish a multi-rigid body dynamics model of the foundation brake rigging in RecurDyn software. And then, take a research on the lateral shift of brake beam and the pressure distribution of shoes for empty and loaded wagon on four kinds of curves braking respectively. At last, to testify the simulation results theoretically, analytical method is used to derive lateral force of the brake beam. The results indicate that the lateral shift of rear brake beam which lead the shoe moving close to the flange is the cause of flange wear, and the positive pressure between wheel and shoe of one wheel-order bigger than others is the cause of tread wear. The research accomplishments above provide technical support for further improvement of the foundation brake rigging in railway wagons.

In this paper, a theoretical mechanical model for the brake shoe is set up according to the foundation brake unit of railway freight cars, and it indicates that the friction moment is the origin resulting in brake shoe eccentric wear. On this basis, the pressure distribution formula on the brake shoe is derived when the train brakes in forward and backward direction respectively. The analysis results show that if the wheel and the brake shoe are concentric, the ratio of the revolving-in end pressure to the revolving-out end pressure in wheel forward revolving is larger than that in wheel backward revolving. It is consistent with the phenomena that upper eccentric wear often appears on the brake shoe in practice. Further research reveals that the degree of the eccentric wear is determined by the braking force action style, which is the theoretical basis for the design revision. In addition, the RecurDyn Multi-body Dynamics software is used to build the rigid-flexible coupling dynamics model for the foundation brake unit. The simulation experiment verified the analysis result. The research outcome provides the theoretical basis and technical support for further design improvement of the foundation brake unit in railway freight cars.

The coupler is used to connect the vehicles, and to transfer and ease longitudinal force and impact force generated by the train running or shunting operation; hence it plays a vital role on vehicle-running safety. The parts of coupler are shaped by casting forming, with some forming error. The process of unlock, full open and lock, (three postures operation) are realized through the motion collision of these components. The forming error will influence the accuracy of coupler motion. However, there is no established theory or techniques to support the research towards the reliability of the motion. By making use of RecurDyn, simulation software for the 13 type coupler, authors carried out multi-body kinematics and dynamics modeling and simulation analysis, and predicted the up-lifter rod max not extract angle when the coupler is unlock with forming error. Meanwhile, authors established a basis process which contains construction and analysis of contact impact mechanism model, simulation geometry modeling, multi-body kinematics dynamics model and simulation analysis. All the efforts lead to one conclusion: the max up-lifter rod not extract angle is 25.5°,when the coupler is unlock. The outcome provides a simulation analysis method for predicting the motion veracity of railway freight car coupler with the features of space mechanism.

The foundation brake rigging is an important part of the railway freight cars, as it is an actuator of the rolling stock for deceleration and stop to ensure essential device for running safety. The mechanism clearance of the foundation brake rigging has a great influence on the brake shoe eccentric wear in the braking and releasing process. Especially during the braking process, the contact area between the brake shoe and the wheel tread is very small, resulting in the contact area with high stress. Actual operation manifests that on the upper side of the brake shoe wear severely. In order to build and analyze the model of the mechanism with clearance, the foundation brake rigging for the rigid-flexible coupling and multi-body dynamics simulation is carried out with the RecurDyn software, which provides the flexible body analysis module-FFlex. The method of resolving the problem is proposed, which includes the original model format conversion, the model preprocessing, constructing the rigid-flexible coupling dynamics model and analyzing the simulation results, and then providing the theoretical and technical support to improve the foundation brake system for railway freight cars by analyzing the main factors of influencing brake shoe eccentric wear.