title: A nondestructive method for estimation of the fracture toughness of CrMoV rotor steels based on ultrasonic nonlinearity.
abstract: The objective of this paper is to develop a nondestructive method for estimating the fracture toughness (K(IC)) of CrMoV steels used as the rotor material of steam turbines in power plants. To achieve this objective, a number of CrMoV steel samples were heat-treated, and the fracture appearance transition temperature (FATT) was determined as a function of aging time. Nonlinear ultrasonics was employed as the theoretical basis to explain the harmonic generation in a damaged material, and the nonlinearity parameter of the second harmonic wave was the experimental measure used to be correlated to the fracture toughness of the rotor steel. The nondestructive procedure for estimating the K(IC) consists of two steps. First, the correlations between the nonlinearity parameter and the FATT are sought. The FATT values are then used to estimate K(IC) using the K(IC) versus excess temperature (i.e., T-FATT) correlation that is available in the literature for CrMoV rotor steel.
authors.affiliation: Division of Mechanical and System Design Engineering, Wonkwang University, Iksan, Chonbuk 570-749, South Korea. hjjeong@wonkwang.ac.kr
authors.forename: Hyunjo
authors.initials: H
authors.lastname: Jeong
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Nahm
authors.forename: Kyung-Young
authors.initials: KY
authors.lastname: Jhang
authors.forename: Young-Hyun
authors.initials: YH
authors.lastname: Nam
mesh_terms: D004868:Equipment Failure; D008422:Materials Testing; D011210:Power Plants; D013232:Steel; D014465:Ultrasonics
chemical_list: D013232:Steel