NovaStark
Mechanical
- Feb 11, 2013
- 255
Hello all,
I am currently trying to perform a level 1 assessment on a though wall crack with dimensions a = 0.28 (wall thickness) and 2c = 0.75 inches within the parent metal.
The current piping dimensions are 6 NPS Std wall with design conditions of 50 psig @ 400F.
From 579, the 1-t curve for A would be used in figure 9.15.
However my issue arises when I am reading off the temperature on the x-axis.
The x-axis has T-Tref+100 (in deg F) and Tref = 38 degF. So I'd get 400-38+100 = 462 degF.
The chart plateaus off after about 160 degF and ends at 200 deg F so that 2c = 2.5 inches (it is a little above this like 2.7 or so but all intents and purposes for my query, 2.5).
Intuitively, I would think that the higher the assessment temperature, the lower the acceptable crack length would be due to reduced allowable stresses. But the chart may lead me to believe that once the temperature is above 200, the value of 2c defaults to 2.5 inches. If my intuition is correct, how do I account for this higher temperature that isn't on that chart ?
I am currently trying to perform a level 1 assessment on a though wall crack with dimensions a = 0.28 (wall thickness) and 2c = 0.75 inches within the parent metal.
The current piping dimensions are 6 NPS Std wall with design conditions of 50 psig @ 400F.
From 579, the 1-t curve for A would be used in figure 9.15.
However my issue arises when I am reading off the temperature on the x-axis.
The x-axis has T-Tref+100 (in deg F) and Tref = 38 degF. So I'd get 400-38+100 = 462 degF.
The chart plateaus off after about 160 degF and ends at 200 deg F so that 2c = 2.5 inches (it is a little above this like 2.7 or so but all intents and purposes for my query, 2.5).
Intuitively, I would think that the higher the assessment temperature, the lower the acceptable crack length would be due to reduced allowable stresses. But the chart may lead me to believe that once the temperature is above 200, the value of 2c defaults to 2.5 inches. If my intuition is correct, how do I account for this higher temperature that isn't on that chart ?
