CRITICALITY IN FABRICATION
- Concentricity of the top middle shell with top flange, middle flange and bottom flange. Due to height of the shell(125mm) it is very difficult to maintain the Ovality. But we have maintained the same by designing the fabrication fixture.
- Closed joint (Without Backchip) of top assembly with bottom shell. During the welding there is no access for back chip and purging also. We have developed the attachment for purging.
- UT examination by ILTR probe of above closed joint.
- Assembly of the ISS with Thermal Baffle.
CRITICALITY IN FABRICATION
- Layout preparations for petals of Hemisphere.
- Petals Cutting and forming for R-1065 and thk 30mm 6 nos. for upper and lower half hemisphere each.
- Fit up of hemisphere and L/seam welding and controlling the R-1065 within 1 mm and its height during welding.
- Lower and Upper half welding and maintain height during C/Seam welding.
- N2 Nozzle and N3 Nozzle welding with Sphere and maintain its individual concentricity and perpendicularity with N1 Nozzle and Middle forging.(It should be within 1mm)
- N4 welding with outer shell and its UT examination by ILTR probe.
- Concentricity of Top Flange, Middle Forging and Bottom N1 Nozzle. We have achieved this within 3 mm. It is very huge assembly having height 5270 mm and sphere O.D.2190 mm.
- Fixture design for the middle C/seam welding ( Top assembly with Sphere welding)
- RT of the N2 and N3 nozzle.
CRITICALITY IN FABRICATION
- Welding of K-Joint having depth 110 mm and Circumference 1900 mm.
- This is T type fit up, it is very difficult to maintain concentricity between Vertical shell O.D. and Bottom flange O.D. But we have achieved this concentricity within 1mm with help of four plumb and dial gauge method at two positions.
- Heat input control is very critical for this huge forging welding but we have achieve it within 1200J/mm.
- UT calibration Block design for K-Joint.
- UT examination by ILTR probe of K-Joint. Our job cleared for the same in first stroke without any repair.
CRITICALITY IN FABRICATION
- Top & Bottom Flange with shell fitment and maintain concentricity.
CRITICALITY IN FABRICATION
- Maintain drilling accuracy.
- Radiography of perforated long c/seam joint of Shell & Cone
CRITICALITY IN FABRICATION
- Die Preparation.
- Dish forming.
CRITICALITY IN FABRICATION
- Baffle Knuckle forming and its Radiography testing
- UT of corner joint of the TOP flange with shell by ILTR Probe.
- Baffle welding with shell and maintaining its concentricity with top, middle and shell ID (within 2mm).
- Achievement of ISS is the concentricity of top flange and bottom flange maintained in fabrication within 1.7mm.
- Welding distortion control for this type of critical material is within 3 mm in height.
- We have done critical fittment of height 5.2m. without optical instrument .
CRITICALITY IN FABRICATION
- U shape bellow forming in two halves and welding.
UT examination of close butt joint welding without back chipping by ILTR probe. In this welding we have face two challenges 1) During closed butt joint welding we have to control total height (welding with Control distortion). 2) No defect is accepted. These things we have achieved by doing root pass RT, then UT at 50% fill up of weld.
- We have achieved these both joints defect free and also we have maintain the required height
CRITICALITY IN FABRICATION
- Maintain concentricity of Bottom Shell, Middle Cone & Top Ring- - - Maintain diameter in two halves
CRITICALITY IN FABRICATION
- Fixture design for hard facing at OMPLAS.
- Welding of inner shell to the bottom flange without back chipping. Maintain the constant gap between inner and outer shell within 1mm in fabrication.
- RT and UT of the Final weld joint.
CRITICALITY IN FABRICATION
- Maintaining the ovality of shell after welding.
