Hello
Does some have good knowledged in CTOD Testing.
We did a Project 7 yeaars ago and the Specification was:
- CTOD Weld Metal
- Thcchiness 22.2mm
- NP direction ( like Charpy Trasnverse direction)
- Sample B x 2B therfore 20 x 40mm (20mm is the B = 22.22 minus the machined ) 20mm)
- Temperature -10°C
- A/W = 0.45 to 0.55
- CTOD was 0.3-0.4mm
Now for the current project we have
- CTOD Weld Metal
- Thickness 23.4mm
- NQ direction (Notch from Internal Diameter of the pipe)
- Temperature -18°C and +75°C
- A/W = 0.45 to 0.55
- CTOD is 0.15-0.2mm
The previous Value were 0.3 to 0.4mm wheras now we have 0.15 to 0.2mm
That we see is that the temperature is not essential as -18°C versus -10°C as CTOD -18°C is equite egual to +75°C. +/-0.05mm CTOD.
As the Sample was B x 2B with 40mm of thickness and therfore as A0 = 20mm the thickness wasA0 20mm versus A010mm
As I know from CTOD testing the CTOD must be performed for thickness more than 12mm to avoid surface effect. (and not less). The fact is that with A/W = 0.5 the thcikness is now 10mm.
Note that the chapy are egual for the previous Job and the new job around 100J at the same temperature.
My question is:
Why did we get 0.4mm and now we have 0.2mm for the same consumable? What is the interpretation to have?
Remind:
NP vs NQ direction
BxB vs Bx2B Samples
Thanks