Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
(OP)
I wish to repair a crack in Fillet weld of a support plate on one of the 02 lifting lugs on a vessel. The material is A 516 Gr.70.
Thickness of plate of Lug is approx. 25 mm. What can be the best welding procedure for repair ?
Do we require a local Srtress relieving or the whole vessel needs SR ?
Which can be the best welding electrode for this reapair ?
Thickness of plate of Lug is approx. 25 mm. What can be the best welding procedure for repair ?
Do we require a local Srtress relieving or the whole vessel needs SR ?
Which can be the best welding electrode for this reapair ?





RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
1. Remove the crack using a burr grinder and grind until the defect is removed or you reached the parting line of the weld joint.
2. Clean the repair area and verify defect removal using WFMT (wet fluorescent magnetic particle) or LPT (liquid penetrant test).
3. Apply a local preheat of 200 deg F, and hold for 15 minutes before welding.
4. Use the SMAW process and E7018 H4 (low hydrogen) weld rod.
5. After the completion of welding, perform a local post weld heat treatment of the repair area at 1100-1150 deg F for 1 hour at temperature. I would suggest using electric resistance heaters with TC's to monitor post weld heat treatment temperature.
The entire vessel does not need to be post weld heat treated. The size of the band for post weld heat treatment should be based on the requirements in the National Board Inspection Code (see RD-1100) or I would suggest using a circular band that encompasses the entire weld repair region with a temperature gradient at or less than 250 deg F/ft away from the weld region.
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
thanks for a good advice. i shall be doing the activities , but apprehensive about the post repair NDT as the temp. wd be high . wd MPT be right choice ?
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
Yes, I did not address post repair NDT, which must be performed as part of this repair. I would suggest wet fluorescent MT after the weld cools to ambient temperature.
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
Use WFMT after the weld repair is completed. My suggestion for MT or LPT in step 1 was to assure the defect was completely removed before welding. There is no requirement for RT.
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
Joe Tank
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
Good point. In some cases it can be difficult to determine the root cause because with fillet welds, I have seen root cracks propagate to the weld face because of IP or a large notch (workmanship problem), lack of fusion, etc. If this is a one time defect in a saddle plate fillet weld, I would repair it and let it go. If this happens again or more develop over time, you have a definite problem related to design.
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
This is just a fillet weld on a lifting lug. I don't understand why the PWHT? Just wanna know.
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
RE: Repair of Weld Crack on SA 516 Gr.70 lifting Lug Welding
The saddle plate thickness is reported to be 25mm, and I would presume the shell thickness is at least 25mm, maybe less. Considering the base metal thicknesses and the presumed size of the fillet weld throat and intended application, I felt PWHT would be a conservative approach.