Yes considered it but how to identify low strength electrode now?
I have a question and if someone has any experience regarding it, please share your thoughts;
1- What if we weld repair the cracks and perform PWHT of all welds (Even though vessel is originally non-PWHT)? API 574 recommends...
Weldstan and Edstainless;
At one location, welding capping was grinded up to 1mm but crack appeared as such. Since we did not find cracks in other welds of the vessel so most probably these cracks are due to built in stresses at fabrication times.
I am more interested in finding cracks depth...
EdtSainless,
No structural analysis is performed yet. All cracks are present in one weld and max length of crack is 8mm as found in MPI. We would mainly be focusing on monitoring cracks growth in periodic inspection. We are trying to check crack depth by UT but it has limitations due to vessel...
First of all, I would like to thank you all for your responses.
Vessel diameter is 2200mm and cylindrical height is 2600mm. Vessel thickness of 6mm is already mentioned in my previous post. Corrosion allowance is 2mm so we can get along with 1.2mm thickness loss. Vessel design temp is 60 C while...
A caustic vessel 6mm thick (epoxy lined)remained in service for 40 years. 1.2mm uniform thickness loss was found in 2021 and two indications (cracks) were found in shell to shell weld. Vessel is originally not post heat treated.
I need suggestions for following maintenance activities;
1- Is it...
PAUT was performed to check external cracks depth and presence of cracks on ID. No crack was detected on ID surface while cracks on external surface are too tight. Calibration of the PAUT tool was done and checked on hot metal surface with cracks on it.
Since Benfield service requires heat...
r6155 and GDD thanks for your comments.
GDD you are right about elbow manufacturing. Its a long radius ASTM A234 WPB elbow. Though there are 7 other elbows of same size/material on the same circuit and all are perfectly ok in VI. Unfortunately quality reports are not available as this fitting...
We have a CS 20"-12.7mm THk elbow installed on rich benfield solution. Operating Temp: 123.5 C while pressure: 29.5 Kg/cm2. Line is stress relieved as per process design conditions. Benfield CS lines are monitored against thickness loss. Particular elbow was found with multiple surface cracks on...
Exchanger soap film test is a common practice to identify the leaky tubes.
Instead of masking tape use rubber corks which are available in the market to cover each tube hole. If exchanger is fixed tubesheet then you need not to use the test ring for fixing the tubesheet but you have to use test...
Some circuits at petrochemical plant are being monitored online against flow accelerated thickness loss. These circuits include BFW, HC, LC, Blow Down, Acid circuit and Benfield circuit etc. Please confirm the followings;
1- Recommended practices for inclusion/exclusion of certain fittings
2-...
Thanks very much for your response.
I appreciate your concerns of catastrophic failure of the high press/temp pipe. I was just interested knowing similar failure experiences and creep deformation for my understanding. In our case pipe was taken in service in 1979 and it got failed in 2021 after...
Carbon steel (ASTM A106) was mistakenly installed on very high pressure steam piping (Pressure: 108 Kg/cm2 and temp: 495C) of a ammonia-urea fertilizer plant in 1979. As per design specifications, material of construction should be A335 P11. Now in August 2021, we faced creep rupture of the dia...
