A Study on Statistical Properties of Vickers Hardness of Friction Welded Parts in Alloy718 Steel (Part 1. As-welded)

J. Ocean Eng. Technol. 2008;22(5):87-93.

Kwon Hyeok-Yong,Choi Sung-Yoong,Lee Sang-Yeal,Kong Yu-Sik,Kim Seon-Jin

Graduate Student School of Mechanical Engineering Pukyong National University,Graduate Student School of Mechanical Engineering Pukyong National University,Department of Automotive Engineering Pohang College,Graduate Student School of Mechanical Eng

Alloy718 마찰용접재의 비커스 경도의 통계적 성질에 관한 연구 (As-welded 재의 경우를 중심으로)

권혁용,최성웅,이상열,공유식,김선진

부경대학교 기계공학부 대학원,부경대학교 기계공학부 대학원,포항대학 자동차계열,부경대학교 기계공학부 대학원,부경대학교 기계공학부 대학원

Keywords: Friction welded part, Vickers hardness, Base metal (BM), Heat affected zone (HAZ), Probability distribution, Weibull distribution, Variation

핵심용어: 마찰용접부품, 비커스 경도, 모재, 열영향부, 확률분포, 와이블분포, 변동

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.