Accurate Measurements of Longitudinal-wave Velocity in IIW-Type Clibration Blocks

Published

October 16, 2008

Author(s)

T Lerch, M C. Renken, C M. Fortunko

Abstract

A proposed ISO standard, based on the draft European standard prEN 12223, specifies that the longitudinal wave velocity in Type 1 Calibtration Blocks shall be measured within a tolerance of 0.1% I.e. with an uncertainty of +or-}6 m/s for compressional waves, based on an assumed true value of 5920 m/s for low-alloy steel. However, ASTM E 494-85 Standard Practice for Measuring Ultrasonic Velocity in Materials states that absolute velocity readings may vary sometimes by as much as 5%, and relative velocity readings by as much as 1%. To help harmonize the ISO and ASTM standards, ASTM Committee E-7 on Nondestructive Testing asked NIST, as an independent group, to address the inconsistencies between the two standards. In response, we have derived expressions for estimating the various sources of error in the time-of-arrival of the signal and made velocity measurements in a laboratory setting for different experimental guidance on how to meet the proposed measurement tolerance in both laboratory and practical environments. We show that, in general, it is very difficult to achieve the proposed tolerance of 0.1% using measurement techniques suggested in prEN 12223.

Citation

Review of Progress in Quantitative Nondestructive Evaluation

Pub Type

Journals

Keywords

IIW-type blocks, ultrasonic velocity measurements

Citation

Lerch, T. , Renken, M. and Fortunko, C. (2008), Accurate Measurements of Longitudinal-wave Velocity in IIW-Type Clibration Blocks, Review of Progress in Quantitative Nondestructive Evaluation (Accessed November 8, 2024)