Welding is one of the processes of making metal structures, which plays a significant role in determining the quality of the weld, the welder or the welding operator, therefore, according to the definition standard, a welder is: someone who has the ability to deposit healthy weld metal. It also says about the operator who has the ability to work with welding equipment. Many parameters are involved in the qualification of the welder, which are known as basic parameters. These parameters may change according to different processes. Their importance is that by changing them, the welder must be certified again. To confirm the qualification, the welder must prepare a sample (Test Coupon) and weld according to the approved welding procedure. Some of the basic parameters that are common in different standards are:

• Welding process
• The thickness of the part and the thickness of the welding layer
• Base metal material
• Welding type BW / FW
• Sample tube or sheet
• Diameter pipe
• Type of filler metal
• Welding position

Some important codes and standards according to which welders are certified:

• ASME Sec IX ( Boiler and pressure vessel code)
• AWS D1.1 (Structural Welding of steels)
• EN 287-1 (Qualification test of welders – Fusion welding – Part1: Steels)
• ISO 9606-1 (Qualification test of welders – Fusion welding – Part1: Steels)