PISTON-RING irons are not the “best-wearing” irons, contends Mr. Lane in his discussion of bore wear from the standpoint of the materials commonly used for high-speed automotive diesel and aircraft-engine cylinders, liners, and rings. Measured on a weight-loss basis under direct comparison with other conventional iron structures, piston-ring irons normally give relatively high weight-loss figures. But piston-ring irons do have the significant and desirable faculty of wearing away with very little tendency to accumulate wear products on their rubbing surface. In fact, this ability is probably of equal or greater importance than actual low weight loss. In his paper Mr. Lane reports the results of several years of laboratory wear-testing research, correlated in many instances with actual service experience, from the viewpoints of hardness, structure, and chemical composition.
Variations in the structure and wear of automotive cylinder castings are illustrated along with the tendency of different type cast irons toward scuffing and scoring, and the cause or reasoning for such tendencies, from the standpoint of the nature of the metal structure, is pointed out. Wear balance and compatibility, through hardness and structural relations, are reviewed, and arbitrary wear values are shown for many of the hardened steels and other alloys frequently used for cylinder and liner applications.