AmritR
Mechanical
- Oct 15, 2007
- 3
I have a question as regards to patch repairs on a Reformed Gas Waste Heat Boiler.
A collegue of mine working in a methanol plant indicated that there was a bulge and crack on the channel head of the boiler. Apparently a tube leak occured and overpressured the channel head. The channel head failed at the longitudinal weld as expected (hoop stress being greater). The affected region aprox 50" by 15" was cut and rewelded using a bent plate of same material. Material being 13 CrMo44 in Hydrogen Service.
Two issues were noted:
1. The orignal plate to be rewelded was miscalculated say 40" by 15" short by 10". The extra 10" by 15" was therefore rewelded to make up for the miscalculation. Three longitudinal welds were therefore present for the patch repair and two circumferential welds.
2. No hydrogen bake out was initially attempted prior welding.
What concerns do you have based on the ASME code for
a. The additional long weld?
b. No hydrogen bake out?
Regards
Amrit
A collegue of mine working in a methanol plant indicated that there was a bulge and crack on the channel head of the boiler. Apparently a tube leak occured and overpressured the channel head. The channel head failed at the longitudinal weld as expected (hoop stress being greater). The affected region aprox 50" by 15" was cut and rewelded using a bent plate of same material. Material being 13 CrMo44 in Hydrogen Service.
Two issues were noted:
1. The orignal plate to be rewelded was miscalculated say 40" by 15" short by 10". The extra 10" by 15" was therefore rewelded to make up for the miscalculation. Three longitudinal welds were therefore present for the patch repair and two circumferential welds.
2. No hydrogen bake out was initially attempted prior welding.
What concerns do you have based on the ASME code for
a. The additional long weld?
b. No hydrogen bake out?
Regards
Amrit