inspecting weld access holes.

Date 09-21-2005 21:24

Traditionally, we've had to MT the access area as AISC Manual Steel Construction Section5-Chapter J-1.8 required it to be done and of course lately because FEMA/AISC Seismic does also.
What is the acceptance/rejection standard? If you see any sign of a linear by MT, is it rejectable? Or should we be using material discontinuity limitations stated in AWS D1.1-2004, Section 5.15 and Table 5.4?? Or some other reference such as ASTM A6??
THANKS.

By swnorris (****)

Date 09-21-2005 21:49

SamCMS,

Section J1 item 8 does not require MT of the weld access holes UNLESS the access holes are made in materials from Groups 4 and 5, or in built up shapes of material greater than 2" thick. If you read all of 8., the last sentence basically states that weld access holes in other shapes need not be ground nor inspected by MT.
FEMA 350 requires weld access holes to be preheated to a minimum 150 degrees Fahrenheit prior to thermal cutting, ground smooth to 500 micro inches (bright metal), and inspected for cracks using either PT or MT. Access holes are permitted to be sawed or drilled without grinding, but still require either PT or MT.
To the best of my knowledge, ASTM A6 does not address criteria for weld access holes. A6 addresses dimensional tolerances, chemical composition tolerances, and rolling tolerances.

By SamCMS

Date 09-22-2005 17:30

AWS D1.1-2004 states C6 (page453)
FEMA 353(2000) Section 4.4, Section 5.8.2
Whats your opinion Mr. Norris?...In my opinion FEMA 353 tells me that if i see a discontinuity with MT is has to be fixed.
Thank You for your help.

By swnorris (****)

Date 09-26-2005 21:41

I agree. MT acceptance criteria is based on the size of the actual surface discontinuity, not the MT indication, except for discontinuities located below the surface or those on the surface that cannot be visually seen after removal of the indicating medium.

By R. Johnson (**)

Date 09-23-2005 15:08

I would like to point out that just because you have a linear indication, you may not have a linear discontinuity. You need to determine if the indication is a relevant indication. MT can be susceptible to non-revelant indications due to geometry of the part being inspected.