Paper Title
Desgin and Development of a Time-Dependent Load wear Testing Machine with Enclosure for Steam Environment

Abstract
Measurement or estimation of loads experienced by a Tribological pair used in an engineering application, supported with explanatory simulations is essential to determine the wear life of the Tribological pair. A detailed study of various loads and motion characteristics of a mechanical face seal used in a Rotary Union (RU) was done in a prior study [1]. Such RUs are used in the paper manufacturing industry to connect stationary steam inlet pipes and rotating paper dryer cylinders. The contact pressures to be achieved in pin on disc wear tests in constant loading conditions were evaluated. In addition, three different amplitudes and frequencies of sinusoidal loading to be replicated in the wear tests were obtained. In the present study, the design and development of a pin on disc Time- Dependent- Load Wear Testing (TDLWT) machine with enclosure for steam environment suiting the above requirement is discussed. Constant loads were applied on the pin using dead weights. An arrangement consisting of a scotch yoke mechanism, springs and an induction motor was used to create a time dependent sinusoidal load. Three springs were designed to obtain 3 different amplitudes for the load curves. The arrangement was enclosed in an environment chamber and designed to maintain up to 0.6 MPa of saturated steam. A torque sensor was included in the drive mechanism to evaluate frictional torque. To validate the performance of the test rig, commercial grade antimony impregnated graphite pins were wear tested on 304 grade Austenitic Stainless steel discs. The results of wear rate Vs static load show that the wear rates of the pins increase with increase in static contact loads initially and then decrease for 2 grades of Antimony impregnated graphite pins. Frictional torque Vs Time graphs showed a gradual reduction from a maxima to a steady state for the three lower applied constant loads. As constant load values were increased, there were abrupt variations in the frictional torque with respect to time. The wear rates of pins under time dependent loads are seen to be less than the average of the wear rates obtained at the maximum load and the minimum loads in constant wear tests. Keywords - Curve Fitting, Time Dependent Loading, Steam Environment, Impregnated Graphite, Pin On Disc Testing.