UT Lucite Wedges

By CHGuilford (****)

Date 12-13-2008 15:46

Sorry, but I don't understand what you are asking for. Can you explain further?

By fbrieden (***)

Date 12-13-2008 15:52 Edited 12-13-2008 23:12

Sorry Chet,

I need to know the material thickness range in which each wedge should be used.

By CHGuilford (****)

Date 12-14-2008 02:27

I'm not sure if this is what you're loking for but take a look at D1.1 Table 6.7. I'm still wrapping my brain around that but it shows the wedge angles to use for various joints and thicknesses up to 8 inches. It looks to me like the limitations on wedge angles is not so much the thickness but the orientation and location of possible flaws.

I'll bet others (John Wright, kipmank, NDTIII, etc) can give you a better answer.

By jwright650 (*****)

Date 12-15-2008 18:20

The thicker the material, the longer the sound path...so a steeper(lesser numerical) angle wedge is used to keep attenuation in check and allow you to remain in the first or second leg while inspecting. Take a look at the Notes under Table 6.7.

Draw the sound path out to scale and take notice of the surface distance required for each of the angles.(or do the math)

By fbrieden (***)

Date 12-15-2008 18:32

Thanks John! It also makes sense.

By CWI555

Date 12-15-2008 21:21

Sound path distance per degree for a single leg exemplified below:
(T / cos of the angle)

45 degree: 2.83"
60 degree: 4"
70 degree: 5.85"

at 8"

45 degree 11.31"
60 degree 16"
70 degree 23.39"

It's a considerable leap in volume of material to transfer energy through.

Regards,
Gerald

By jwright650 (*****)

Date 12-16-2008 12:43

"(T / cos of the angle)

45 degree: 2.83"
60 degree: 4"
70 degree: 5.85"...."------Quote

Just a note to add for clarity:
Thickness = 2" in this example shown above

By hogan

Date 12-15-2008 16:10 Edited 12-15-2008 16:42

fbrieden,
6.20, 6.26, and table 6.7 gives you some minimum requirements for UT in accordance to clause 6. If you are outside of these requirements then you need to go to annex S. 6.26.6.2 also give some guidance, although I feel it is very vague. It states that: It is intended that, as a minimum, all welds be tested by passing sound through the entire volume of the weld and the HAZ in two crossing directions, wherever practical. The way I read this the last two words negate the requirement.