2g Saw (Final Ppt) (1)

Development and Implementation of

2G SAW on C3 Splitter

Sanket SinghWelding TechnologyISGEC Hitachi Zosen Ltd

2

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.

6

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.

13

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

14

Picture 1: Execution of PQR Picture 2: Bead Placement

Execution of PQR

15

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)

20

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 % )