How to Perform Visual Inspection of Weld Seams?

A quality visual inspection of welds is not limited to a mere glance at the weld seam. Visual inspection must be carried out according to standardized requirements that define very precisely all the practical aspects of weld seam quality control.

Specifications for Visual Inspection of Weld Seams

The international standard that provides guidelines for the execution of quality visual inspection of weld seams is the EN ISO 17637 standard.

Some specifications include:

The accessibility to the weld seam must be sufficient for the eye to be located less than 600 mm from the surface to be observed and at an angle not less than 30 degrees.

La norme internationale sur le contrôle visuel de la qualité des soudures est EN ISO 17637

The lighting of the surface:

  • Type of light:     white
  • Minimum :         350 lx
  • Recommended: 500 lx

The weld quality control report must include the following information:

  • the name of the manufacturer of the component
  • the name of the control organization, if different from the manufacturer’s name
  • the identification of the controlled object
  • the material
  • the type of assembly
  • the material thickness
  • the welding process
  • the acceptance criteria
  • welding imperfection  exceeding the acceptance criteria and their position
  • the extent of weld inspection illustrated where appropriate by drawings
  • the welding control devices used
  • the result of the control in relation to the acceptance criteria
  • the name of the inspector and the date of the weld quality control

The EN ISO 17637 standard (2003 edition) cites as information examples of classic measurement tools for weld seam control. BEWARE that all tools available on the market from 2003 to today are MEASURING tools, therefore it is very important to keep in mind that it is impossible to immediately qualify a defect as acceptable or not acceptable.

Measurement tools are divided into two types:

1. Vernier-type measuring tools

2. Gauge-type measuring tools

Classic measuring tools make visual inspection of welds very difficult.

User testimonials

The VT® gauge principle is GO or NOGO. Measurements, calculations, and manipulation of standards are not involved.

Guy Lardinois SPRL Company

VT© gauges provide significant benefits for welders by reducing training needs. The approach is highly practical and easy to comprehend. The gauges offer excellent value-addition to welding processes. It is a precise and efficient solution.

There's no need to comply with elaborate standards or conduct complex calculations for visual weld quality control. For instance, for craters, visual inspection is now immediately possible without any calculations. The VT© gauge and a flashlight are all that is required to handle any welding situation. By saving an enormous amount of time and ensuring precision, VT© gauges provide a valuable addition to the welder's toolkit. Training requirements are minimized. The approach is highly pragmatic, and it is straightforward to determine the appropriate gauge with the help of available visual aids.  

10 / 10

Institut Belge de la Soudure (IBS)

The use of VT© gauges enables visual inspection by non-experts. They are suitable for all types of welding profiles and are cost-effective.

VT© gauges facilitate a visual inspection without requiring an engineering background or extensive consultation of data tables.   This allows for a visual inspection to be conducted in accordance with the welding standard without the need for advanced technical skills.This streamlined inspection process is quick and efficient, eliminating past difficulties with visual inspections. Now, anyone can perform a visual quality control of welds without requiring engineering expertise. It is accessible to individuals across all professions and at an affordable price point.

10 / 10


The new generation of VT© weld inspection gauges is very easy to use and highly accurate. Our trainees show great interest. We use ultra-modern, state-of-the-art equipment

Industry has a chronic shortage of boilermakers and pipe fitters. For boilermaking, the TechnoCampus assembly site is the only training operator to offer short or long courses for the entire Walloon Region. Each instructor at the assemblage site has his or her own complete VT Total kit. Instructors demonstrate the handling of the calibers to trainees and companies, both as part of our teaching and continuing training courses. We also organize information days with the guidance of the IBS (Belgian Welding Institute). We use gauges for all approvals. Thanks to the combination of the new generation VT© gauge and the ultra-simple instruction manual, our instructors can certify to EN 1090-2 very efficiently. The new generation VT© gauge for weld inspection is very easy to use and highly accurate. Our trainees show great interest. We use ultra-modern, state-of-the-art equipment, including welding simulators.

10 / 10