Fillet welding of shell to bottom joint of API 650 Tanks
hamza ahmed
Hi,
Can anybody describe the maximum gap allowed between shell to bottom joint of API 650 tank. It is a ' T ' joint requiring fillet weld. Bottom plate thickness is 10 mm and shell plate thickness is 12 mm. Also please descirbe the relevant API 650 or ASME IX paragraph.
With Regards.
Ahmed |
shah B.K
For shell to bottom weld gap is not required. Shell Plate should be completely contact with bottom plate.
Regards
B.K.Shah
SAUL VASQUEZ T.
The gap is not relevant to this joint we work without gap and maximum gap 2-3 mm. where you can not close.
5.1.5.7 Shell-to-Bottom Fillet Welds
a. For bottom and annular plates with a nominal thickness 13 mm (1/2 in.), and less, the attachment between the bottom edge of
the lowest course shell plate and the bottom plate shall be a continuous fillet weld laid on each side of the shell plate. The size of
each weld shall not be more than 13 mm (1/2 in.) and shall not be less than the nominal thickness of the thinner of the two plates
joined (that is, the shell plate or the bottom plate immediately under the shell) or less than the following values:
hamza ahmed
Hi Mr. Shah,
Yes, I totally agree with you. But here due to some fabrication and erection mistake, there is a gap of 10 mm. As per AWS D1.1, upto 5mm can be accepted. As applicabe code is API 650, I wanted to know if there is any reference in this code.
With Regards
Ahmed Husain,
ABS TPI
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hamza ahmed
Hi,
As I wrote in previous mail, due to fabrication and erection mistake, the gap between first course of shell plate and bottom plate is upto 10 mm at some places. In case there is no reference in API 650(Applicable code), what would be the corrective action. Any advise.
Warm Regards
Ahmed Husain
ABS-TPI
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Date: Monday, April 6, 2009, 6:42 PM |
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PB HEGDE
Hi,
Gap between the shell plate and bottom plate will cause severe distortion resulting in crack.
i)As such gap up to 0-2mm do not cause any problem of crack. Ii) Now to reduce the gap one of the edges to be chamfered by grinding and butter on the edge by welding, By this method reduce the gap. Iii) Tack weld by higher dia. Electrodes with sufficient length and numbers iv) While fillet welding use higher dia say 4/5mm electrode (If welding by SMAW) this will give higher thickness weld, which will give sufficient strength and use sequential welding. iv) Preheating and post heating is essential to avoid crack and distortion v) If possible preferably fillet welding to be carried both side of the joint simultaneously so that there will be less distortion.
Hope this will solve the problem
Warm regards
Hegde P.B.
+9114714803