QA QC Welding Inspector Interview Questions

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Jobs in the welding field are numerous and diverse. With dedication, commitment and the right preparation, the industry can provide you with a long and rewarding career. 

One path that’s worthwhile to consider as you map out your welding career path is a job as a QA/QC welding inspector. Here, we’ll share more details about this position and help you ace the interview with sample QA/QC welding inspector questions and answers. 

What is a QA QC welding inspector?

QA stands for quality assurance while QC stands for quality control. A QA/QC welding inspector examines welds to ensure they’ve been performed according to the pertinent requirements and are up to all applicable codes and standards. They accomplish this using a combination of nondestructive testing methods and by overseeing the entirety of the weld process.

A QC/QC welding inspector plays a direct role in the safety and usability of the resulting product. As such, they must be knowledgeable about the relevant standards for the materials and structures they’re inspecting and must know where to turn to quickly locate the applicable code information. They need to have a thorough knowledge of welding processes and understand how different materials react under different conditions. 

Welding inspectors can be certified at varying levels through the American Welding Society (AWS). AWS’s Certified Welding Inspector (CWI) program can help propel you into an engaging and lucrative career with a job like a QA/QC inspector. 

QA QC welding inspector interview questions to look for

Use the following sample questions and answers to prepare for your QA/QC welding inspector interview.

1. How do you conduct a visual inspection of a weld?

Visual inspection, also called visual testing, can often be the easiest welding inspection method to perform and is usually the least expensive to conduct. When done correctly, this method can be incredibly effective to ensure acceptable weld quality and prevent problems.

Sample answer: Even if other nondestructive testing methods will be performed on the weld, I normally prefer to conduct a visual inspection first. Firstly, visual inspection can identify surface discontinuities, which can sometimes skew the interpretation of other NDT results or hide other discontinuities within the weld. In a visual inspection, I use my experience and expertise to identify discontinuities like undercut, under fill, overlap, surface cracking, surface porosity, burn through, and more.

2. Describe the difference between ‘hardness’ and ‘toughness’ as it pertains to welding.

In everyday conversation, most of us use these words interchangeably with little difference in their meaning. In the context of welding, though, the words ‘hardness’ and ‘toughness’ refer to two very different properties. A metallic product can be hard without being tough, and vice versa. 

Sample answer: Hardness describes how a material stands up to abrasive wear and indentation. To use diamonds as an example, they’re one of the hardest materials on earth since they’re almost impossible to scratch. Toughness describes how well a material stands up to force without fracturing. To be tough, a material must be both strong and ductile, which allows it to deform without breaking. To continue the diamond example, a diamond is hard but not tough. If you take a hammer to it, it will easily fracture. 

3. Why would a welder pre-heat a steel pipe before welding?

Preheating is a crucial step in many welding applications. Though it takes more time up front and adds a step to the process, it can save time and money in the long run by lowering the potential for a weld failure down the road. Here, describe your understanding of this welding process step. 

Sample answer: Preheating the material to be welded slows the cooling rate, which can help prevent cracking and reduce residual shrinkage stress during cooling. The thicker the material is, the higher the likelihood it needs to be preheated. Preheat is applied via an artificial heat source, like an electrical resistance heater or gas torch.

4. What does DMW mean?

It would be great (and save a lot of time) if all welds joined the same materials. Of course, this isn’t practical and would seriously limit innovation. Construction, automotive and manufacturing, among other industries, all necessitate joining dissimilar materials to save on production costs or use the most efficient material for every part of the finished product. 

Sample answer: DMW stands for dissimilar metal weld. This is the term for welding two distinct materials that have different chemical and mechanical properties, like carbon steel and stainless steel. To execute a DMW, you must consider various factors including chemical makeup, solubility, strength levels and weldability of both the individual materials being joined as well as how they will interact with one another. 

5. Describe your understanding of welding quality control systems.

The ultimate goals of QA/QC welding inspection are to ensure the integrity of the final welded product and to make sure the welding process is optimized so as not to have negative impacts on business. Having a documented quality control system makes these objectives possible. 

Sample answer: Quality control describes a documented, strategic set of procedures for weld testing and weld monitoring. In welding, this is defined in the Welding Procedure Specification (WPS), which may stipulate weld techniques, workmanship criteria, code acceptance criteria, and more. ISO9000 is the industry benchmark for quality management; it outlines all aspects of an effective quality control system.

6. What is the difference between PT and MT?

Different circumstances call for different types of inspection, and part of your job as a QA/QC welding inspector will be to determine the appropriate test methods to use. Knowing the nuances between different types of testing is essential to select the most fitting testing method for each product, structure or material. 

Sample answer: PT and MT each have pros and cons. While PT can be used on both ferromagnetic and non-ferromagnetic materials, it can only detect surface discontinuities and is only applicable for a limited temperature range. Though MT can only be used on ferromagnetic materials, it can detect both surface and subsurface discontinuities and is applicable over a wider temperature range. MT is also faster than PT. 

7. What are some of the limitations of eddy current testing?

Just as it’s necessary to know the differences between the types of testing, it’s equally important to understand the limitations of each method. No one method is applicable in all cases; that’s why having a thorough grasp on the full range of test methods is so valuable to an inspector. 

Sample answer: The main limitation of eddy current testing is that the material being tested has to be electrically conductive. Even in conductive materials, eddy current testing can only detect discontinuities at the surface and a small distance beneath it, limiting its reach. Finishes and coatings applied to a material’s surface can also limit or skew the measurements from eddy current testing. 

8. What welding styles would be appropriate to create a corner joint?

Used on the outer edge of a piece where two parts meet to form a right angle, a corner joint is one of the most widely used welds. They’re necessary in the construction of boxes, box frames, and many, many other types of fabrications. 

Sample answer: Just a few of the types of welds you could use to create a corner joint include a fillet weld, spot weld, V-groove weld, U-groove weld, butt weld or edge weld. 

9. What is the standard for structural steel fabrication?

The welding industry is built on a foundation of codes and standards. Without these, products would break, bridges would fail and buildings would, quite literally, collapse. As a QA/QC welding inspector, one of your primary job requirements is to know/be able to find which standards apply to the materials and processes at hand so you can apply them in your work. 

Sample answer: AWS D1.1 is the standard for structural steel. It outlines standards for material and design, fabrication, inspection, qualification and more. AWS D1.1 Structural Steel is one of the many endorsements offered by AWS to help welding inspectors expand their skills and increase their earning potential. 

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