Search Results

For many years the ASTM D2882 test method, using the V-104C Vane pump, served the industry well to evaluate the lubricating properties of hydraulic fluids at low pressures (< 2000 psi). However, at higher pressures in different types of pumps (i.e. piston pumps), this method may not be reliable enough to predict satisfactory lubrication performance in commercial applications. In this paper the V-104C pump will be evaluated in terms of vane contact force and film thickness parameters to assertain the possibility of using a modified bench test to better predict hydraulic fluid performance at higher pressures.

Cavitation is the dynamic process of gas cavity growth and collapse in a liquid. These cavities are due to the presence of dissolved gases or volatile liquids and they are formed at the point where the pressure is less than the saturation pressure of the gas (gaseous cavitation) or vapor pressure (vaporous cavitation). In this paper, various hydraulic system design factors and fluid properties affecting the cavitation process, and bubble collapse mechanisms will be discussed. In-situ generation of cavitation, examination of the cavitation process in model hydraulic systems, material effects and test methods will be reviewed.

There is increasing interest in the development of bench tests to characterize the performance of hydraulic fluids in order to minimize the cost of testing and the volumes of fluid currently required for pump testing. One method which permits comprehensive characterization of the boundary, mixed EHD and EHD wear regimes encountered in pump lubrication is to develop a performance map. This paper discusses the use of this testing method to characterize the performance of two experimental hydraulic fluid formulations.

The ASTM test method D-2882 (Standard Test Method for Indicating the Wear Characteristics of Petroleum and Non-Petroleum Hydraulic Fluids in a Constant Volume Vane Pump) is widely used to evaluate hydraulic fluids. Performing this method can be difficult due to problems with the pump hardware and the written procedure. This paper discusses the problems and suggests possible remedies.

Atmosphere carburizing remains one of the most important surface treatment technologies throughout the world. In this paper, various important metallurgical design variables are identified by examining the results of the carburisation of 15HN steel. These results showed the importance of the formation of martensite-retained austenite-carbide microstructure after hardening. Increasing austenization temperature causes a decrease in the carbide fraction and an increase in the fraction of retained austenite. By optimisation of the composition of these microstructures through variation of carburisation process, hardening, and tempering variables, it is possible to optimise compressive stresses, abrasive wear resistance, and contact fatigue resistance.

Thickened water-glycol hydraulic fluids, which are generally suitable for use at system pressures of < 34.5 MPa have been used by the fluid power industry for over forty years. The principle reason for the use of this class of fluids is their outstanding fire safety properties. However, when higher system pressures are encountered and fire safety is required, a polyol ester or phosphate ester based fluid is usually selected. Recently, a proprietary, thickened water-glycol based fluid has been developed for use at system pressures of up to 34.5 MPa. The fire safety and performance testing results of this fluid will be described in this paper.

One of the most commonly used tests to evaluate the antiwear properties of a hydraulic fluid is ASTM D 2882 which is based on a Vicker's V-104 vane pump. Although this is a commonly used test, the results are subject to numerous potential problems in both testing procedure and pump hardware. In this paper, the particular focus will be placed on potential problems that may be encountered with testing of water-glycol hydraulic fluids which may lead to erroneous and non-reproducible results.