tomsing
Aerospace
- May 19, 2010
- 48
In the Atlas of Stress-Strain Curves, 2nd ed, in chart AS.005 ( they present 3 charts of tensile stress-strain curves up to yield for 4130 at room and elevated temps for three different heat treatments. Now, first of all, the labeling of the charts is a bit odd - they refer to the "Left", "Center", and "Right" charts, but they're arranged on two rows and labeled like this:
(a) (b)
..(c)..
Based on the nominal strengths listed in the caption - Left is 150 ksi, Center is 180 ksi, and Right is 200 ksi - I'm pretty sure that the order is
(150) (200)
...(180)...
So that's one thing. The other thing is, check out the modulus on chart (c). The RT curve crosses right at .004 strain, 100 ksi, for a modulus of 25 Msi, when I'm expecting something closer to 29-30. If you check charts (a) and (b), they go through .004 strain, 120 ksi, for a modulus of 30 Msi, just as expected. So I think chart (c) is in error.
The caption references WADC TR 56-340, as published in Aerospace Structural Materials Handbook, Vol 1, Code 1201. Unfortunately, I've been unable to find either of these. Does anybody have a copy?
(a) (b)
..(c)..
Based on the nominal strengths listed in the caption - Left is 150 ksi, Center is 180 ksi, and Right is 200 ksi - I'm pretty sure that the order is
(150) (200)
...(180)...
So that's one thing. The other thing is, check out the modulus on chart (c). The RT curve crosses right at .004 strain, 100 ksi, for a modulus of 25 Msi, when I'm expecting something closer to 29-30. If you check charts (a) and (b), they go through .004 strain, 120 ksi, for a modulus of 30 Msi, just as expected. So I think chart (c) is in error.
The caption references WADC TR 56-340, as published in Aerospace Structural Materials Handbook, Vol 1, Code 1201. Unfortunately, I've been unable to find either of these. Does anybody have a copy?