NDTsi 2001 Session: Advances in Non-Ultrasonic NDE Methods
Evaluation of PWHT Temperature For Low Alloy Steel Girth Weld Joint by using AC Magnetic Probe Method
M. Shiwa, G. Chen, Y. Horii, H. Yoneyama, JAPEIC, Japan
ABSTRACT
The AC magnetic testing method of high exciting frequency (60kHz) by using a small coaxial probe was proposed to evaluate the PWHT temperature, non-destructively. The waveforms of AC magnetisation in low alloy steel girth welded joint specimens (1.25Cr-0.5Mo steel and 2.25Cr-1.0Mo steel) were investigated under several PWHT temperature conditions. It was found that the normalised 3rd harmonic component intensity (Fh3) of the detected signals, which was defined as the ratio of the 3rd harmonic component intensity to the fundamental harmonic component intensity, changes considerably related to the PWHT temperatures. The regression curves based on the measured Fh3 value, were formulated to evaluate the PWHT temperature as the master curves. The evaluated PWHT temperatures based on the master curves agreed with the actual PWHT temperature very well. Also influence of the surface condition on the testing result was investigated. Two types of surface treatment, chemical polishing (CP) and mechanical polishing (MP), were used in the test. Measurement after the CP surface treatment gives more reliable results. Keywords: AC magnetic method, PWHT temperature, Normalised 3rd harmonic component intensity.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
