We have about a dozen supercriticals in the US and all use P22 for main steam. Design temperature is lower though at 538 C. If we were building a supercritical with 565 C temps, we would likely use P91.
If the welding is performed to ASME IX, then a welder qualification on groove welds qualifies for all fillet sizes in all thicknesses of material. For grrove welds, the welder is qualified for a maximum of 2 times the deposited weld metal thickness for each welding process used in the...
..or you could insert heavier wall P22 pipe in the F91 fitting, stress relieve the F91 to P22 joint, then weld P22 to stainless with a F22 coupling using Inconel electrode. Make sure you can size the P22 pipe and F22 fitting for the pressure/temperature involved.
Don't forget it also requires a minimum of 3 layers of weld in addition to the 1/2" of weld deposit per process. This would need to be recorded on the Performance Qualification Record for the welder to be qualified for unlimited thickness.
The X42 is going to require a heavier wall thickness than the X65. So a transition piece will need to be made from X65 of the same wall thickness as the X42 that is counterbored at the other end to match the X65. Preheat temperature and welding electrode should be based on the X65. Other than...
I should have also mentioned that for performance qualification, QW-423.1 provides a table that shows the P- or S-Number used in the test in the left column vs. the P- or S-Numbers that may be welded in the right column. It also shows that (for performance qualification) a test using an...
Section I does not have specific limits on heating and cooling rates such as those found in ASME B31.1. Section I paragraph PW-39.3 has the following words:
"The weldment shall be heated slowly to the temperature specified in Table PW-39 and held for the specified time, and shall be allowed to...
You do not need to reference the PQR in the welder's performance qualification form. The WPS is usually recorded on the form, but is not required. The required information is values for each essential variable, type of tests and results, and ranges qualified (see QW-301.4).
A WPS qualified...
After seeing Dr. Masuyama's slides on the effects of chemistry changes and cooling rate changes, I think cooling rate is just as important as chemistry. There seemed to be some unspoken key to the manufacturing process that V&M overcame by having a 4:1 Ti/N ratio to ensure sufficient free...
The maximum interpass temperature is limited to 100 F above that measured during the welding procedure qualification and recorded on the PQR per supplementary essential variable QW-406.3 in ASME Section IX. That variable also says that the limit applies unless PWHT is performed above the upper...
metengr
What happened with T23 at the November 2008 TG-CSEF and SCII meetings? I'm hearing rumblings there was a move to withdraw the code case due to concerns over low hardness values after normalizing and the chemistry range being too broad for some elements. Can you shed any light on this?
The inspections should be focused on conditions that would present a concern. These might be leakage, pitting corrosion, cracking of welds, etc. I would start with a good visual inspection of all accessible surfaces for evidence of pitting, weld cracking, staining that might indicate areas of...
A good write-up on the failure. But, I'm still not clear on the cause. Was the riser tube failure described as corrosion fatigue or was it flow accelerated corrosion? Also, it sounds like the dead air space was pressurized by the tube failure and resulted in an "explosion" which could have...
