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Qualification of welding processes

Welding has always been the most critical permanent metal joining process, which is why certifying the process is synonymous with repeatability of the process with quality assurance.

The most effective way to control the quality of a good welding is to destroy it; bend, fracture, traction, resilience tests are therefore carried out.

A joint shall be certified when all destructive tests, and not in accordance with applicable standards, have given a positive result.

The welding inspectors of the company Solving UNI.on, have decades of experience in the carpentry industry thus allowing efficiency and expertise for our customers. The qualification of a welding process is a requirement increasingly demanded by companies operating in the industrial and manufacturing sector. It allows to indicate the ability to satisfy the design requirements and the control of the mechanical characteristics according to the type of base material, contribution material and the welding procedure to be used.

The certification of welding processes allows companies to obtain several advantages:
  • The certainty of providing the market with a safe and reliable product
  • Avoid disputes from customers and end-users
  • Provide the market with the image of a company attentive to compliance with mandatory requirements and safety and technologically advanced
There are a number of standards indicating how to prepare the welded qualification joints, the laboratory tests to be carried out, the characteristics of the test pieces, the criteria for acceptability of the test results and the heading of validity of the qualification.
WPS and WPQR
The WPS (Welding Procedure Specification)The WPS (Welding Procedure Specification) provides all the parameters involved in the welding process and is the essential tool for recording the data used for the qualification of the procedure and/or the welder.These parameters are those used for the actual production of welded joints (production WPS).
During the execution of the welding tests, the technician records and verifies the actual conditions of realization of the joint in question noting:
  • welding parameters
  • basic materials
  • filler materials
  • protective gas
  • welding technique

WPQR (Welding Procedure Qualification Report)

At the end of the laboratory tests, if the results meet the acceptability requirements of the standard, the procedure shall be considered qualified and a WPQR shall be issued, that is, a qualification report of the welding procedure, drawn up in accordance with the requirements of the reference standard which shall include:

  • the laboratory results
  • the actual welding conditions
  • Validity fields according to the reference standard

Therefore, the welding parameters and conditions recorded in the qualification ratio can be used in the production joints realization.

Attention: once the welding process is certified, if no changes are made to the process itself, the certification does not expire! The certification of the process is also closely linked to the company and not to the welder or the operator who performs the welding.

SCOPE OF WELDING PROCEDURE QUALIFICATIONS.

The qualification of the welding procedure, with reference to the parameters indicated in the WPS, has a well defined validity range that depends on a number of variables.

These variables are: • the type of welding procedure (MAG, MIG, TIG, Coated electrode, Plasma, Submerged arc, etc.); • the base metal to be welded (carbon-manganese steel, stainless steel, aluminium, etc.); • the type of components to be welded (tubes, Sheet, etc.); • the type of joint and its preparation (head-to-head, V-shaped, X-shaped, T-shaped, corner-joint, etc.); • soldering on one side, with or without support and on both sides, with or without groove on the reverse; • the diameter and thickness of pipes and sheets; • the classification of filler materials (solid, cored wires, coated electrodes, protective gases, etc.); • electrical parameters, such as welding speed, thermal input, voltage, current intensity, etc.

A careful application of the rules allows the qualification of the entire welding activity with the minimum number of procedure and welder qualifications, thus obtaining the total planning of the welding production process.