ASTM Distance-Amplitude Blocks

By Thunderhead Date 02-10-2009 12:55

I need to manufacture a set of distance-amplitude blocks for straight beam UT of some welds, I am looking at ASTM E428-99 for the manufacture of the blocks. The question I have is the range. My range will need to be 3/4" - 8". I want to create a DAC for this size range. I'm a little unsure how many blocks required to cover this range and really need clarification of the hole size. Thanks for any input.

By Bill M

Date 02-13-2009 17:44

What Code allows for straight beam inspection of welds?

By kipman

Date 02-14-2009 16:14

Thunderhead,
We often use straight beam to UT welds, specifically from the back side of t-joints or inclined t-joints. We use API RP-2X (very much similar to AWS D1.1 Appendix S), and as such we use ASME style basic calibration blocks for sensitivity calibration. For straight beam calibration, we use modified blocks that take into account the fact that you may be travelling through a significant amount of through-member base material before you get to the weld. I recommend that you evaluate the option of using a basic calibration block instead of distance-amplitude blocks - they are easier to make in house for most operations (you don't need to make flat bottomed holes).
Mankenberg