UT Indication Rating per AWS

Date 10-22-2008 15:19

I have a question for you AWS UT guys. It's been a long time since I worked to AWS.

When determining an indication rating per AWS you use the calculation a-b-c=d.

I am scanning a butt weld in 5/8"t plate with a 70 degree transducer.

I remember how to derive b and c. How exactly do I determine a?

Thanks in advance for your help.

By kipman

Date 10-22-2008 15:24

Ed,
When you calibrate sensitivity you pick your own screen height from the 1/16" hole, say 50%FSH. The dB level here is your "b".

When you find an indication max it out and adjust the gain to bring the indication to 50%FSH. The dB level at this point is your "a".

So "a" is your indication and "b" is your reference sensitiviy level.
Mankenberg

By mroach

Date 10-22-2008 15:55

NDT III & Kipman. Need one more step to determine the indication rating, "Attenuation Factor" "c". Subtract 1" from the sound path and multiply the remainder by 2. Without this step the formula cannot be completed to establish the indication rating. Just remember to round out to the nearest whole value.

By CWI555

Date 10-22-2008 16:09

assuming standard and not metric you mean.

By mroach

Date 10-22-2008 16:59

Never seen a metric conversion to the indication rating formula. If there is one I would be interested in reading up on it.

By kipman

Date 10-22-2008 17:15

The conversion is to multiply by 0.08 for SI units. This was an editorial oversight that has been ongoing all the way through the 2008 edition of D1.1. It will be corrected for 2010.
Mankenberg

By mroach

Date 10-22-2008 17:59

Certainly appreciate that bit of information. I'll definately make a note of that.

By CWI555

Date 10-22-2008 18:19

looks like people are playing with the ratings again.

By kipman

Date 10-22-2008 18:27

Hah! I like it, Gerald! Too bad the ratings aren't a, b, c, and d!
Mankenberg

By NDTIII

Date 10-24-2008 18:08

Thanks guys! Appreciate it!