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Petal to petal long seam welding by SAW

Eliminating need of heavy duty Turn Table

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Description

Task in hand - Welding of 6 Dishends

(Petal to Petal long seam) of the following jobs in MFS1

Project No.s - 23199 A, B & C Customer - KJV Dish end diameter - 4000mm, Weight - 12 Tons Total kg deposition - 550 kgs. Planned process - SAW Planned resources- Column & Boom,

Aranson positioners

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Constraints

Bottleneck - One Aranson Positioneer available for welding 6 D’End long seams.

Frequent breakdowns of the turn table during the first D’End welding adversely affected manufacturing schedule .

PTC qualified for SAW welding.

MMA welding would have been a costlier option.

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Conceptual stage

Requirement:- Eliminate need of Turn table

D’Ends will be connected together and positioned inside the fixture. Long seams to be welded by placing the D’End along with fixture on Tank Rotators.

Fixture

Hemispherical D/E

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Initial Preparation:

Two Dished End’s are positioned on top of each other and joined together to get a perfect Sphere while maintaining the trimming lines parallel to each other.

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Two half Rings bolted together.(Rings were available)

Pipes connecting the two rings.

Clamping bolts to hold the D/E firmly in position.

Segments cut to suit the D’end outer profile.

Design Features

7One long seam is welded at a time , 4 seams of D’ends can be welded in one set up.To weld 6+ 6=12 L/S , set up needs to be changed three times.

Long seam welding in progress.

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After welding 4 long seams the bolts on the upper half of the fixture are loosened to make the D’end free inside fixture and the D’end is rotated to set the next set of 4 seams for welding.

Long seams welded

Long seams positioned for welding.

Long seam welding in progress.

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Back Chip welding of Petal to Petal long seam by SAW using the same fixture which otherwise would have been welded by SMAW.

Further Development.

SAW Boom

Welding Head

Gap between two D’Ends.

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Contribution:

Conceptualization , design & manufacturing.

(Production Engineering HEW)

- R.V. Mahajan

- K. A. Khochare

Execution:

(MFS 1 - Service and Assembly shop)

- R. N. Parikh

- A. G. Surve

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Future Plan

Similar design will be adapted for the following D’Ends with improvised fixture design to reduce the set up time.

1. 23200 - Dia. 5140 x 53 thick - 20 T

2. 23222 - Dia. 3864 x 50 thick - 9.5T

3. 23211 - Dia. 3330 x 40 thick - 4.9T

Total 6 hemispherical D/Es