Any time one welds an austenitic stainless steel precaution is required to ensure that the corrosion resistance of the stainless is not destroyed. To avoid this problem I always list a maximum interpass temperature of 120C.
I would also suggest that you consider using "poison pads" onto which...
Marko,
There is something wrong with the quoted vibration when considering fatigue damage potential. The value quoted is a velocity. What you need is the displacement, which you may have to get from an acceleration. ie, F=ma. The acceleration will depend not only on the pump, but the stiffness...
The 2010 edition of ASME VIII-1 does not allow for UT substitution for RT for other than checking a repair and in this case the UT must first confirm the RT finding.
I think it unlikely that the Code Committee will accept UT in lieu of RT any time soon, as the AI can look at a film, but...
API 579/ASME FSS-1 is in part a cook book standard. For simpler analysis, you follow a step by step procedure that is well laid out. The step by step approaches are necessarily conservative and do not cover all circumstances. API 579 spells out the limitations of each procedure.
TGS4 is...
Jim,
Code requirements require pressure relief on boilers so there should be relief valves present already. These could be left at there current setting as they are to be set relative to the maximum operating pressure of the boiler and not at the actual operating pressure which must be equal to...
Steve,
Unless you have major work done to the pressure envelop ( through wall construction), a hydro test is not warranted. The ASME test requirements are really only a leak test. You could jeopardize the structural integrity of the vessel foundation, vessel support, or the vessel itself by...
Colin,
Lamellar tearing occurs in thicker plate sections because during rolling most of the compression takes place near the surface (redundant deformation), so imperfections in the material are fragmented more severely at the surface than in the core of the material. With thinner material, the...
For clarification, permitted stress values are applicable regardless of the method employed to determine stress in a material as the permitted stress values are a Code consideration for safety. The Code also recognizes "shakedown" which is localized plastic flow. What the Code does not permit is...
Colin,
If the vessel material and repads are thicker than 1/2", you need to consider the risk of lamellar tearing as you will be developing significant through-wall stress. If this is the case, do a complete area UT scan (need a machine with a CRT) to check for laminar indications. Also...
As the studs are not welded to the pressure envelop, you should be able to reweld the studs without consideration of the affects on the envelpo, however if you want to take extra care, use a temper bead weld procedure as per the provision of UCS-56 in Div 1
For creep hot spots, the risk is a localized fracture. You need to do a fracture mechanics analysis to determine expected life. You can use the method in API 579, or British Standard PD7910. I would assume the determined locallized stress value for my analysis as my experience with creep...
