Friction Resistance between Valve Made of TiAl Alloy and its Guide Made of Phosphor Bronze

Abstract

A lightweight valve is often made of TiAl alloys and its stem can be solid or hollow. Such valves can mate with guides made of cast iron or of phosphor bronze at different conditions in their contact zone valve/quide. The aim of the research was to measure the friction force in the sliding contact between the valve stem made of TiAl alloy and its guide made of phosphor bronze, in the absence of oil. The experiment was conducted at room temperature and in static air under normal pressure. The investigations were conducted with use of the tester, which is presented in this article. The loading of contact zone has varied periodically during series. The displacement and acceleration of valve and the force during its impact into seat insert have been measured during tests. Additionally the sound level has been measured, either. Tests have been provided for different frequency of driving force. Additionally, researches on the tribotester pin-on-disc, presented in the article, have been provided, with the pin made of Ti6Al4V alloy and the disc made of phosphor bronze. The model of research stand has been elaborated for the simulation of dynamics for the material sample rotating plate assembly. The aim of such researches has been to obtain values of coefficient of friction for such tribological pair and to simulate dynamics of the material sample rotating plate assembly, characteristic for used research stand. The obtained courses of coefficient of friction vs. loading, slide velocity, duration of motion of material sample in respect to the rotating plate have been presented in the article. On the base of simulation results the values of damping coefficient have been estimated, which allow to obtain the value for the amplitude of the modeled motion for the material sample in respect to the rotating plate near to the value of the amplitude for the real motion. Such estimation allows forecasting the dynamics of the mentioned assembly for other values of velocity and loading.