Advanced Materials Research Vol. 900

Abstract: The traction characteristics of lubricant is one of the important parameters of the dynamic performance of bearings design .This paper chose three significant factors affecting the traction coefficient：temperature、load and rotate speed. Test results showed that the traction coefficient under the high load is significantly higher than under low load from room temperature to 135 °C. After more than 135 °C, the traction coefficient under the low load is higher than under the high load. It illustrated that the grease was sensitive to temperature but it reflected high temperature stable performance.The optimum conditions were obtained by Design-Expert software optimization : temperature for 235°C、load for 2800.00N、rotate speed for 183.17r/min and in this time the traction coefficient is at 0.547 in this test. It shown that the grease fitted the low speed and heavy load equipment.

Abstract: The systems of DLC film/304 stainless steel were separately treated with cryogenic treatment,annealing treatment and composite treatment of cryogenic+annealing to study the effects of different treatments on friction and wear property of DLC film/304 stainless steel,mainly from the film’s hardness,fracture toughness and surface roughness. The results show that the friction and wear property of DLC film/304 stainless steel is improved in different degrees by the three kinds of treatment,single cryogenic treatment performs best. It is because that three kinds of treatment all can improve the fracture toughness of DLC film and reduce DLC film’s surface roughness,but only single cryogenic treatment doesn’t reduce film’s hardness and makes film get the best lubricity and highest hardness-to-elasticity ratio. The residual stress of film/substrate composite system can be effectively adjusted by cryogenic or annealing,but annealing often sacrifices DLC film’s hardness as the price.

Abstract: There are many reasons for having a lubricant within the engine besides that of reducing friction. However scrupulously clean the engine is maintained, there will always be a small amount of dirt or impurities that find their way inside. That dirt must be removed before it can cause damage to bearings or block small oil passageways. The oil can be used to keep the engine clean by carrying dirt to the oil filter where it is strained out and where it remains until replacement of the filter. The majority of the bearings within the engine are manufactured from steel, a metal which would soon oxidize itself if it were not prevented from doing so by a liberal coating of oil, thus the lubricant will also minimise corrosion inside the engine.

Abstract: This paper describes the structure and operational principle of OFVA used in OFW, and the electromagnetic force characteristics are obtained by FEM (finite element method) and measurements. The coupled magnetic field-circuit-motion simulation model which is driven two-phase symmetric sinusoidal voltage sources is established and the motion trajectory is simulated.

Abstract: With the help of the orthogonal experiment and the friction-wear mechanism by car as the research object of the clutch driven platen friction plate of Chongqing Changan CX20 auto power take-off installation, the optimization of clutch friction materials is studied.It was selected for the resin-base fiber materials of clutch driven platen to be commonly used in auto mechanical manufacture. It was analyzed for the abrasion mechanism of the clutch driven platen friction plate between the flywheel and the pressure plate,and discussed for the relationship of driven platen friction-plate heat recession-performance and the driven plate material at high temperature. The results show that the friction factor of the optimized driven platen lining materials do not change. In the process of the frequent friction heating to high temperature, the stability of the optimized driven platen lining materials is strong, the wear of those is reduced, and the optimized driven platen lining materials have good performance of high temperature-thermal recession.

Abstract: The purpose of this study is to investigate the fire possibility of the cotton packages by the friction heating during the transportation by train. Theoretical simulation was conducted for the friction heating with a typical amplitude and frequency. The results suggest that the hot point induced by the sliding friction between the iron string joints around the package and the iron floor is the heat source for the heat transfer progress. It is also illustrated that the calculated temperatures on the surface of cotton package near the friction point are still a little lower that the rapid pyrolysis temperature of cotton material in a rather worse situation. However, more and more heat may accumulate inside the cotton package if there is a long-time heating for it. The smoldering of the cotton packages may still happen and turn into a cotton fire in train when there are also some other factors at the same time.

Abstract: Friction and wear behaviors of aluminium matrix composites reinforced with in-situ formed TiB₂ particles were measured by MMW-1 friction testing machine under the different loads and rotation speeds. SEM, heating microscope and XRD were utilized to research the friction and wear behaviors. The results showed that the friction and wear property was improved by addition of TiB₂ particles.

Abstract: In order to deal with Hertz contact problem of friction drive in continuously variable transmission (CVT), two methods were proposed in this paper. One is a numerical computation method by MATLAB to solve the elliptic integral equations of Hertz contact, while the other is a finite element method (FEM) which uses the ANSYS Workbench to calculate the point contact between two elastic bodies. The computation results of Hertz contact problem of friction drive in a new CVT proposed by our research group show that, compared with a look-up table method, the numerical solution of MATLAB has many advantages such as high precision and less computational cost, while the finite element method has more simplicity and better visibility. The present methods can provide a reference for the solution of Hertz contact problem of common friction drive.

Abstract: Taking the waste heat utilization of sintering circular cooler in Chongqing Iron & Steel Co.,Ltd as an example, the problems of the system have been analyzed and some measures have been presented based on the theory of total energy system in this paper. The result shows the main reasons that the generated energy can only reach the design value of 60% are lower energy grade because of oversintering or undersintering of sinter, the air leakage of waste gas recovery system of sintering circular cooler, frequent short interruption of sinter flow and so on. Some measures which can improve the energy grade of waste heat of sintering circular cooler and increase the generating capacity have been proposed. These measures involve controlling the end point of sintering, improving the operation level of main process, improving sealing technology of the system, recycling the heat of the boiler outlet flue gas, cascading utilization of the heat of third section of the sintering circular cooler, valuing the conversion and utilization between the various forms of energy, such as work, heat, the internal energy of working medium.

Abstract: Relying on the status of existing thermal protection system and existing flight parameters, appropriate metal thermal protection system being able to reproduced are designed. Then, based on the highest temperature thermal protection materials can bear, flying height of aerospace plane and Mach number, the numerical method was utilized to reveal the heat-flow density of stagnation point on the sharp- nose and the distribution of heat-flow density.