Abstract
The objective of this paper is the investigation of the statistical properties of Vickers hardness (HV) of friction welded parts in nickel based super resisting steel, alloy 718 steel. First, we examine the statistical properties on the case of as-welded parts. Several Virkers indentations were made under same nominal conditions. This was repeated for three different applied loads, 100, 200 and 300g with a duration time, 10 second. The arithmetic mean of Vickers hardness in base metal (BM) materials is larger than that of HAZ in all applied loads. The measure of dispersion, that is, the coefficient of variation (COV) for BM and HAZ is decreased by increasing with the applied load. The distribution of Vickers hardness was not found to be symmetric type. The probability distribution of Vickers hardness was well followed Weibull distribution. The shape parameter and the scale parameter (characteristic hardness) are increased by increasing with the applied load, as both BM and HAZ.