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.

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.

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

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.

7

• WELD JOINT NOT CLEAN

• LOWER PREHEAT TEMPERATURE

WELDING DEFECTS

POROSITIES:

• STRONG WIND FLOW ON ARC

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:

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

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

11

• UNBAKED ELECTRODES / FLUXES

• LOW PREHEAT

• INSUFFICIENT POST HEATING

• UNCLEAN WELD JOINTS

WELDING DEFECTS

CRACKS

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