2g saw (final ppt) (1)
TRANSCRIPT
Development and Implementation of
2G SAW on C3 Splitter
Sanket SinghWelding TechnologyISGEC Hitachi Zosen Ltd
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Topics covered Development & Implementation Purpose
Design of WEP
Welding Operator Training and Qualification
Set-Up
Welding Parameters
PQR Establishment
On job execution
Comparison of SMAW with SAW in Horizontal position & Radiographic quality
Process Limitations
Conclusion
Development & Implementation Purpose:
ISGEC HITACHI ZOSEN LTD Job DV-204 (C3 Splitter)
Total Height: 95.7 Meters
Fabricated weight = 660 Tons
Total weld metal deposition required = 8000 Kg
Total weld metal deposited by SMAW per arc hour = 1.5 Kg (Approx)
Total weld metal deposited by 2G SAW per arc hour = 6.0 Kg (Approx)
To meet on time delivery schedule with quality
Resource constraints e.g. Rotator, Cranes
Design of WEP Full accessibility of
2G SAW nozzle tip
Ease of bead sequencing
Adjustment of welding parameters without affecting weld soundness
Welding Operator Training and Qualification
As the process demands dedicated manpower skill, rigorous training andqualification is required to improve knowledge and skill of welding operatorand supervisors for monitoring the welding involved.
Main areas for training
Set Up and Machine Details
Welding Parameters and process principles.
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Set Up
As welding is to be carried out in horizontal position below given points are must requirement
There should be proper access for 2G SAW nozzle within groove.
Arrangement for holding and collecting flux.
Proper arrangement for resting control panel.
Arrangement for movement of 2G SAW head
Arrangement for manipulation of SAW 2G nozzle within groove. (Both To and Fro, Up and down movement)
Welding operator comfortness
2G SAW SET-UPChannel: For movement of SAW frame
Frame with rolls : Formovement in horizontal position
Wire Spool Holder with adjustment clamp
Nozzle, Frame, Flux Pipe, Travel Guide, Flux belt
Flux Pipe
Nozzle Tip with nozzle holder
Flux Belt with Roller support
Travel Guide
Frames
Welding Direction
Roller, Guide & Motor
Stationary Rollers
Drive Rollers
Motor
Mechanism for tightening the stationary rolls
Horizontal, Vertical and Angular movement control knob
Fixed clamp for vertical motion
Angular movement control knob
Horizontal movement knob
Control Panel (Ammeter, Voltmeter, speed indicator)
Speed control
Wire Feed control (Current control)
Pass Current Voltage Speed
Root Pass 450-550 28-32 450-550
Fill Up Pass 450-550 28-32 450-550
Covering Pass 450-550 28-32 600-700
Welding Parameters
Welding parameters for 2G SAW process are more or less similar for Root and fillup pass as it is for Flat position SAW, while the parameters for capping pass isdifferent (speed). Refer below Table 1 for welding parameters.
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PQR EstablishmentPurpose for establishing a PQR Check whether the parameter settings and arrangements are desirable for producing a sound weld metal with minimum problems. To establish a sequence for bead placement. To check weld metal properties after completion of welding to determine the effectiveness of parameters w.r.t to Base metal properties. To establish machine settings for subsequent operation.
Execution of PQR and weld metal Properties:Base material: SA516Gr70Thickness: 56mmConsumable: EH10K + Supershield C4 (Super alloys and Metals)Parameters: Refer Table 1Preheating: 75 0CInterpass: 275 0C
Properties:After 8 Hr of heat treatment at 610-611 0CTensile strength: 485 Mpa ( Failure in Base metal)Hardness: 198 BHN (Max in weld)Impact: 160 J (Min in weld), 101 J (Min in HAZ) at -29 0CMacro: Satisfactory
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Picture 1: Execution of PQR Picture 2: Bead Placement
Execution of PQR
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On Job Execution:
2G SAW was implemented on more than 24 Circular seams (ISGEC Job DV-204), carrying out 4800 KG of weld deposition . Total time involved for completion of welding was 72 days.
2G SAW was applied on following areas
1) Circular seam (Cylindrical shell # Cylindrical shell, refer Picture 3)2) Circular seam (Conical skirt shell # Conical skirt shell, refer Picture 4)3) Circular seam ( Cylindrical shell # Ellipsoidal Dished end, refer Picture 5)4) Fillet Joint (Conical Skirt # Compression ring, refer Picture 6)5) Skirt to Dished end welding (Refer Picture 7 )
On job Execution
Picture 3: Circular seam (Cylindrical shell # Cylindrical shell)
Picture 4: Circular seam (Conical skirt shell # Conical skirt shell)
Picture 5: Circular seam ( Cylindrical shell # Ellipsoidal Dished end)
Picture 6: Fillet Joint (Conical Skirt # Compression ring)
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Picture 7: Dished end to Skirt joint
Picture 8: Weld Aesthetics & Bead placement
Comparison of SMAW with SAW in Horizontal position
Process SMAW SAW 2GProduction 1.5 Kg per arc Hr
(Approx)6 Kg per arc Hr (Approx)
Total weld metal=4800KG
3200 Arc Hr 800 Arc Hr
Saving of arc Hr = 2400 arc Hr by SAW 2G
Radiographic Test Result: Total rejection found 360mm in 360000mm of weld length i.e. 0.1%
Process Limitations
1) Requires WEP w.r.t application.2) Requires skilled manpower to operate independently; semi skilled man power under frequent observation.3) Required special Tools and Tackles. 4) Rigorous training shall be imparted to welding operator for bead placement.
Conclusion:
It is quite apparent from the development process that 2G SAW is very productiveprocess, it is minimum four times faster than SMAW on production scale, theaesthetic look of welds is also very good, the process has produced good resultsin Radiographic Testing. (Total rejection found 360 mm in length of 360000 mmi.e. 0.1 % )