Welding inspection

This article for a newbie or who would like to know about welding inspection and sequence to control your tasks as a welding inspector or supervisor.

Welding inspection are including 3 steps to complete the jobs:

  • Before welding
  • During welding
  • After welding

Before welding

Actions are normal inspect before welding and tool/equipment should available for using and validity.

Procedure and other documents

  • Company's written procedures, visual examination procedure, repair procedure, etc.
    • QC engineer will prepare it and submit to Client.
    • WPS register list must prepare and submit for approval.
    • NDE procedure and NDE personnel qualification.
  • Understanding the specification and code application and acceptance criteria. 
    • For piping process are accordance to ASME B31.3 table 341.3.2, or.
    • For structural steel are accordance with AWS D1.1 table 6.1 for nontubular, table 9.16 for tubular (!!! Important evaluation for the weldment).
  • Personnel qualification and certification of welding inspector, ex. accordance to ASNT-TC-1A or ISO 17637). Read more the requirement in ASME B31.3 or ASME BPVC section V, etc.
  • Approval welding procedure specification and welding process.
  • Approval construction drawings and has issued for fabrication, welding map for trace weld joint, 

Welder performance

Tools and equipment

  • QC tools for inspection like welding gages, tape, ruler, etc.
  • Welding equipment are available and calibrated (may be in-house certification).


  • Material inspection and review its MTC, make sure all parts can traceable the heat number/ code number and in good condition. Read more material inspection.
  • Welding consumables to meet the WPS.
  • Cutting and transfer product marking and beveling inspection.


  • Fit up inspection are including check groove preparation, misalignment, weld joint number accordance with the WPS/welding maps, material being joined accordacnce with IFC drawings.
  • Preheat temperature.
  • Welder qualification who assigns for welding.
  • Set up the welding parameters to meet WPS.

During welding

  • Welding parameter and welding process are accordance with WPS for cerrent, volts, travel speed. 
  • Welding consumable for each process or layers accordance with WPS. The different between root pass (GTAW) and hot/cap passes (SMAW), or low temperature electrode.
  • Temperature are included minimum preheat temperature, maintenance and maximum interpass temperature. 
    • Important on low alloy steel, when interpass temperature was lower than preheat temperature due to preheat was not archive. Learn more how to archive soak heat.
  • Visual inspection root run including root high (protrude inside), root thickness (special for lining metal)
  • Gringing/cleaning of each pass/layers and suitable with base metal (grinding disk carbon steel is prohibited to use for stainless steel).
  • Assigned welder are in the register list and his range of qualification.
  • Weather condition: indoor or outdoor,...

After welding

  • Weld identification such as welder number, drawing number/welding map, WPS apply, date of inspection, NDE requirement.
  • Visual inspection
    • Visual internal cleaning and root high (piping).
    • Weld appearance surface are suitable for NDT.
  • Issue visual inspection report.
  • Dimensional inspection and issue report.
  • Update drawing if any change.
  • PWHT if applicable.
  • Request for NDT and review NDT reports
  • Release for hydrotest or load test, surface treatment and painting, machining, etc.
  • Update in welding summary.

Additional activities

Other tasks welding inspector/QC inspector should follow after welding and NDT.

  • Update welder repair rate and renewal welder performance.
  • Update NDT percentage, if random/spot NDT selection.
  • Notification of inspection to Client for inspection/witnessing.
  • Final documentations.
Nguyen Duy Bien

Enjoy learning and researching, reading book. Knowledge welding inspection painting inspection.

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