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Certified Weld Inspection Services in Melbourne: A Brief Overview on the Process and Procedures

14 May 2020

Many characteristics of a weld can be evaluated during welding inspection – some relating to weld size, and others relating to the presence of weld discontinuities. The size of a weld can be extremely important, as it often relates directly to the weld’s strength and performance. For instance, undersized welds may not withstand stresses applied during service. To know more about the process and procedures of certified weld inspection services in Melbourne.

Certified Weld Inspection Services Function

Weld inspections are conducted for several reasons, the most common of which is to determine whether the weld is of suitable quality for its intended application. To evaluate the quality of a weld, you must first have criteria to which you can compare the weld’s characteristics. Codes and standards developed specifically for a variety of welding fabrication applications are used during welding inspections to dictate what levels of weld discontinuities are acceptable. It is important to choose a welding standard that is intended for use within your industry or application.

A variety of non–destructive techniques is used for weld inspection. Inspection is expensive, never 100 percent effective and may involve destruction of the component. It is aimed at detecting defective workmanship, rather than preventing defects from occurring. It is essential that every effort be made to make the component properly, rather than rely on inspection to identify faults.

Weld Discontinuities

Depending on their size and/or location, weld discontinuities (imperfections within or adjacent to the weld) can prevent the weld from meeting its intended performance. Weld discontinuities are often referred to as welding defects, and they can sometimes cause premature weld failure due to a reduction of strength or added stress concentrations within the welded component.

A deviation from perfection in a material is called a flaw. This includes atomic scale imperfections such as solute atoms, lattice vacancies, dislocations and larger imperfections such as impurity particles. Meanwhile, another form of discontinuity is the non–conformity. It is a flaw that if found, fails to meet the prescribed standard. It does not necessarily cause rejection of the material. On the other hand, a defect is a flaw that when assessed fails to meet the prescribed standard, causes rejection of the material. The material has to be repaired or scrapped.

Less important non–conformities can be inspected for randomly. Where the risk of critical non–conformities (defects) is unacceptably high, 100 percent inspection should be performed. However, no inspection technique is completely infallible. The risk of defective work must be minimised by suitably qualified people carrying out the production work to written process instructions.

Quality Acceptance

Quality acceptance criteria can originate from several sources. The welding fabrication drawing or blueprint will typically provide sizes and other dimensional information, such as length and location of welds. These dimensional requirements are typically established through design calculations or are taken from proven designs known to meet the performance requirements of the welded connection.

Inspection Integrity

Inspectors must not be influenced by those responsible for production and progress. In the past, inspectors have been pressured to accept defective work to avoid cost and schedule impact. The risk to the fabrication is unacceptable. Product failure may seriously impact public or operator safety and risk environmental damage. The fabricator should realise that they are exposed to expensive consequential damage claims.

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