weld defects
DESCRIPTION
TRANSCRIPT
![Page 1: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/1.jpg)
1
IMPORTANT CODE REQUIREMENT AND PRACTICES RELATED TO WELDING
2. Check the seam number on the job.
( A ) BEFORE STARTING WELDING
1. For specific seam : Refer shop weld plan, WPS and test plan.
![Page 2: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/2.jpg)
2
( A ) BEFORE STARTING WELDING
6. Check cable connections and earthing.
IMPORTANT CODE REQUIREMENT AND PRACTICES RELATED TO WELDING
8. Provide run - in, run - out plates for L - seams.
25 mm 25 mm
25 mm25 mm
7. Clean WEP+25 mm on either side. Remove rust , paint, oil etc.
![Page 3: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/3.jpg)
3
11. Use SS wire brush /wire wheel for SS, Inconels , Monels and Cupro-nickels. Do not use grinding wheels used on CS.
9. Get temperature sticks for preheat & interpass. Temperature > Preheat
< Interpass
25 mm 25 mm
BURNER
10. Check preheat at least 25 mm away from WEP on both sides.
IMPORTANT CODE REQUIREMENT AND PRACTICES RELATED TO WELDING
![Page 4: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/4.jpg)
4
IMPORTANT CODE REQUIREMENT AND PRACTICES RELATED TO WELDING
2. Weaving < 3 x Electrode diameter.
( B ) WHILE WELDING
1. Tacks and temporary cleats- Use specified electrodes and preheats - Qualified Welder- No hammering
4. SMAW Electrode left over after 4 hrs - return to stores.
3. No stray arcing on job.
![Page 5: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/5.jpg)
7
• WELD JOINT NOT CLEAN
• LOWER PREHEAT TEMPERATURE
WELDING DEFECTS
POROSITIES:
• STRONG WIND FLOW ON ARC
![Page 6: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/6.jpg)
8
- GTAW / GMAW / FCAW : • RUSTED FILLER WIRE• DAMAGED TORCH- CLOGGED TUBE, GAS PASSAGE• TURBULENT GAS FLOW - USE GAS LENS• INADEQUATE GAS FLOW - FAULTY FLOW METER• FCAW GAS PREHEATER NOT WORKING• GAS PURITY CHECK
WELDING DEFECTS
POROSITIES:
![Page 7: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/7.jpg)
9
• IMPROPER INTERPASS CLEANING
• POOR BEAD FINISH- ROUGH, LUMPY BEADS NOT
DRESSED BEFORE WELDING
• FAULTY RESTART - LUMP AT STARING POINT - TO BE
GROUND
• WELDING PARAMETERS (I,V, T.S) NOT AS PER WPS
• WRONG BEAD PLACEMENT
SLAG INCLUSIONS:
WELDING DEFECTS
![Page 8: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/8.jpg)
10
• LOWER CURRENT
WELDING DEFECTS
LACK OF FUSION / PENETRATION
LFLP
• POOR WEP / SET-UP - LOW ROOT GAP,
HIGH ROOT FACE, LOWER INCLUDED ANGLE
• RUST / PAINT ON WEP
![Page 9: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/9.jpg)
11
• UNBAKED ELECTRODES / FLUXES
• LOW PREHEAT
• INSUFFICIENT POST HEATING
• UNCLEAN WELD JOINTS
WELDING DEFECTS
CRACKS
![Page 10: Weld defects](https://reader030.vdocuments.net/reader030/viewer/2022012314/54ba6ec34a795980708b4677/html5/thumbnails/10.jpg)
12
• HEAVY RESTRAINT- WELD TACKS WITH HIGHER CROSS SECTION
• EXCESSIVE LOCAL HEATING - USE OF RING BURNERS ( NOZZLE# SHELL/ D.END JOINTS )
• USE OF WRONG ELECTRODE / FLUX
• FAULTY CONS. QUALITY / SELECTION
WELDING DEFECTS
CRACKS