THE EFFECT OF TEMPERATURE ON THE MODULUS OF ELASTICITY AND OTHER PROPERTIES OF METALS
Minutes of the Proceedings of the Institution of Civil Engineers
THE physical properties of metals a t ordinary temperatures have been very fully investigated, and the relationship of certain of the properties to the life of material under various conditions of stress has received a good deal of consideration. Most metals, when subject to stresses at ordinary temperatures, obey Hooke's law approximately, if not absolutely, within a certain range of stress, and some metals, such as hot-worked mild steel or wrought iron, do so up to a stress at which a sudden
... at which a sudden change in the rate of elongation takes place, which is called the yield stress. I n other metals, as for example, cold-drawn steels, brasses, and the aluminium alloys, the departure from a linear stress-strain diagram takes place very gradually and only an arbitrary definition can be given to the " yield-point." The object of this Paper is to describe experiments made t o determine the effect of temperature on the ultimate strength, the elastic limit, the yield-point, and the modulus of elasticity of certain metals. The experiments have been carried out amidst pressure of other work and have thus extended over n number of years. The results obtained so far show how quickly some of the properties in question change when certain temperatures are exceeded, and indicate the importance of knowing these effects when metals are to be subjected to temperatures higher than those of the atmosphere. The most important examples are the pistons, cylinders, sparkingplugs, valves, valve-seats and springs of internal-combustion engines, the rotors of turbines using highly superheated steam or hot gases, valves on superheated-steam pipe-lines, and parts of fireboxes especially of locomotives and flash boilers. Downloaded by [ Purdue Univ Lib TSS] on [17/09/16].