What Is Welding Inspection in Simple Words?
Welding inspection uses technological methods to ensure the quality of welds by specific criteria and acceptance standards. Many weld properties can be assessed during the process, some regarding the welds’ size, and others concerning the presence of weld discontinuities (any deficiencies within or adjacent to the weld).
Based on their size and location, welding defects may prevent the weld from fulfilling its essential requirements. Weld discontinuities can often lead to premature weld failure due to reduced strength or increased stress concentrations inside the welded element. Hence, welding inspectors need to meticulously analyze the bonds and connections between metal pieces to assure the safety and quality of welds.
What Welding Inspection Procedures Do Weld Inspectors Follow?
Welding inspectors generally follow various evaluation procedures to carry out a welding inspection. A perfect welding inspection method is Non-Destructive Testing (NDT), which is meant to assess the weld without doing any damage. Here are different types of welding inspection procedures that most welding inspectors follow:
- X-Ray Inspection
- Remote Visual Inspection
- Liquid Penetration Inspection
- Ultrasound Inspection
What Criteria Are Considered for Welding Inspection?
Welds are usually scrutinized based upon the function for which the welding was performed. To inspect and assure the weld’s quality, inspectors need to test a variety of factors as the following:
Weld Distribution
A good weld distribution is when the weld material is distributed equally between the two joint metal components. If there’s no balanced distribution of weld on both metal parts, the joint may become fragile under pressure and result in breakage.
Waste Material
The welding inspector must ensure that the weld is free of any waste material like slag. Welding slag is a type of slag or vitreous material generated as a byproduct of arc welding processes. Slag is, in fact, the hardened flux after the weld zone cools. If the welding slag fails to get peeled away either by itself or after scratching, it may affect the appearance of the joint. That’s why the metal components need to get cleaned properly before welding.
Welding Porosity
Welding porosity refers to a welding imperfection originating from unwanted gasses confined inside the molten weld puddle throughout solidification. It can appear on the surface of a weld or inside the weld bead. Any holes or pores in the weld denote low-quality work and contribute to weld fragility. Holes are generated during welding when the base material is unclean or includes an oxide coating.
Weld Tightness & Leakage
A welded joint needs to be tight and free from any leaks. Weld inspectors usually spread a certain liquid across the weld to make sure there’s no seepage. If it happens, it means the weld includes pores that will fail the welded materials. Other than liquids, inspectors can fill a product with a tracer gas and detect escaping gas using a leak detector. This helps the inspector determine if there’s a leak and where and how big it is.
How to Become a Qualified Welding Inspector
Welding inspection is a broad area of expertise that attracts specialists from various backgrounds. Welders, forepersons, fabricators, NDT operators, and anyone working in the industry can make a qualified welding inspector if they are well-versed in several fields. A welding inspector must have hands-on knowledge of welding drawing and symbols.
Numerous areas can root from a simple welding inspection qualification. It is generally considered a good starting point to move into NDT areas, cathodic protection, plant inspection, coating inspection, and underwater inspection.
Essentially, a welding inspector should always be updated with the latest weld symbols, including the AWS symbols. This helps them be prepared to identify any problems before they develop rather than after they occur. However, welding inspection is far beyond the non-destructive testing of the finished weld. A qualified welding inspector should also have a hand in these areas:
- Review & Analysis of Specifications
- Joint Design
- Cleaning Procedures
- Welding Procedures
Currently, there are numerous welding inspection certification programs and training courses available. One of the most practical is the “Certified Welding Inspector” (CWI) program, which is designed and administered by the American Welding Society (AWS). To become a certified welding inspector, you typically need to demonstrate your expertise through a welding inspection examination.
What Are Typical Responsibilities of a Welding Inspector?
A welding inspector is responsible for ensuring the strength and quality of welding work. Welding inspectors are also required to examine the equipment utilized and ensure welders stick to the safety regulations.
A welding inspector is required to:
- Preside over the whole welding process and observe all actions regarding the weld quality during production.
- Ensure the most appropriate equipment, materials, methods, and techniques are utilized for a welding project.
- Record all inspection details concerning the weld quality, and provide a final report indicating all recognized imperfections.
- Compare all the recorded logs with the acceptance standards and any other criteria mentioned in the reference guides.
The welding inspector oversees the welding work from pre-welding, welding, and post-welding procedures.
In the following post, we will offer a handy welding inspection checklist that enables welding inspectors to analyze and improve the welding work through the whole process before, during, and after welding. Stay tuned to learn more about the complicated world of welding and all it takes to make a brilliant welder and inspector.
