UT basic calibration block material- ABS Guide requirement

Date 03-20-2012 20:39

Dear Experts

ABS Guide for NDE on Hull Welds-2002-Section 3.11.2- "Basic Calibration Block- Material whick the block fabricated is to be of the same product form, heat treatment, material specification and accoustically similar material being examined".

I'm working with Materials like - AH36/DH36/EH/36.EQ51/EQ57 -Series.
Does separate individual calibration/reference block required or block made of ASTM A36 is enough?

This is my understanding of what is staed in ABS Guide:-
1- Product Form - Manufacturing process - Rolling/Forging/Casting..etc
2- Heat treatment- annealing/normalized..etc
3- Mat Specification - Carbon Steel/StainlessSteel /Duplex Stainless Steel Steel/CuNi- need block form same/equivalent material.

AWS D1.1- calls for ASTM A36 or acoustically equivalent material is enough.

Pls explain as detail as possible.
Thanks in advance.

By Bill M

Date 03-29-2012 14:27

Not familiar with the ABS standards

When ASTM specs require calibration blocks they specify a requirement for "accoustically similar material" as well:

from ASTM
"Accustical similarity is presumed when, without a change in instrument setting, comparison of the back reflection signals between the reference block and the examined plate show a variation of 25% or less"