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Flawed Specimen

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NDT-KITS supply high quality flawed specimens for the Nondestructive Testing (NDT) Industry and pressure equipment construction. Our flawed specimens are manufactured in accordance with ASME, API, CSA and other specifications and standards.

We have excellent R&D and manufacture department to guarantee our products with high quality, and we always import new technologies in our flawed specimens manufacturing process. With over 80 standard products, we offer wide range of flawed specimens including Industry Specific Kits and Individual Specimens.

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Why Global Clients Choose Us?

40 Years of Expertise

We have 40 years of experience in the professional production of ultrasonic flaw detectors, an annual output of more than 10,00 ultrasonic flaw detectors, thickness gauges, ultrasonic probes and calibration blocks.

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As of September 2021, we have a total of 125 employees, including nearly 45 professional and technical workers who are masters or doctorate degree holders.

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We have Complete machining workshop, CNC, CNC machine tools, and more than 50 other types of processing equipment,to ensure high-precision product parts.

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We provided excellent after-sales service, including fast delivery, online training,  immediate feedback of trouble shotting.

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Flawed Specimen: The Ultimate Guide

Table of Contents


Have you ever considered where flawed specimens are applicable in ultrasonic flaw detection? 

Many of the ultrasonic calibration devices available today specifically enable flaw detectors to identify specific flaw types. However, some of these flaws don’t frequently occur during production, therefore, leaving little or no room for technical personnel to recognize these defects if they encounter them during production. Consequently, trainers need to put forward a method to teach technical persons how to identify flaws during production.

This guide gives you complete information on how flawed specimens help technicians achieve flaw detection during manufacturing.

So, if you are ready, then let’s dive in together.

I. What is a Flawed Specimen? 

Accidentally causing a flaw within a material or component during production is usually the norm. However, there is usually the intentional side of introducing a flaw into a material or component, often called a specimen that non-NDT individuals don’t know about. Yet this happens and usually for one of three reasons and quite frankly can be very accurate in its dimension. 

One reason can be to test an NDT technician’s ability to accurately locate specific flaws, to test the technician’s ability to size and dispatch a flawed sample. Lastly, another reason is to test an NDT technician’s understanding of a specific code, technique, or industry-standard of inspection. While setting an accurate reference is crucial, you’ll find out that most flawed specimens often come as blocks with SDH (Side Drilled Holes) or FBH (Flat Bottom Holes).

II. How are Flawed Specimens Used in the Industry?

In general, flaws come into the production process one way or another. It is the company’s job to train its technicians to accurately identify defects that they might encounter in the course of their work. But let’s face it, some of these anomalies are not common, and their occurrence can at best come down to a stroke of luck. Consequently, waiting for an event of a flaw on the field before identifying these defects to your NDT personnel might be very expensive and sometimes dangerous. 

Fortunately, the development of flawed specimens has been the right step in the right direction seeing that it offers companies and institutions a very accurate, cost-effective, and efficient method of identifying flaws. The ability to model flaws found in material samples and during certain production activities ensures that NDT personnel can practice identifying defects in materials accurately without having to wait forever for a defective occurrence that might never happen. Sometimes some technicians miss the opportunity when it does occur in the real world as they might be far from the site where it is occurring. They might even be absent on the day. 

It is better and easier to get NDT flawed specimens either as kits, individual pieces, or flawed custom specimens to satisfy specific projects with unique needs like the probability of detection, performance demonstration, or training for a particular qualification.

III. How do we Make our Flawed Specimens?

For starters, making a flawed specimen is often easier said than done because it comes with various challenges. Therefore, to overcome these challenges, many flawed specimen manufacturers use proprietary techniques that have been developed in-house over the years by experienced technicians. For instance, welding defects, including porosity, lack of fusion, slag, incomplete penetration, and inclusions, can be accurately reproduced to size, shape, and location just like you would have them in real-world applications. 

However, crack defects are another kettle of fish entirely. 

The reason is that cracks occur in different sizes and modeling the different crack sizes might be tricky. However, manufacturers use mechanical and thermal fatigue techniques to produce crack defects for a flawed specimen. Also, you can use a hybrid method for modeling certain crack sizes for specific kinds of cracks. Nonetheless, other innovative approaches are available to accurately model flaws based on these cracks modeled to size and location. 

Likewise, for flaws like corrosion and erosion of metals, manufacturers use proprietary techniques like accelerated corrosion to produce realistic models of these flaws, especially for internal parts of tubes and pipes. 

But more importantly, these flaw models must meet testing criteria and customer specifications for the intended testing applications.

 IV. What Types of Flawed Specimens are Commonly Used?

When assessing flawed specimens, it is often a good practice to consider some crucial factors that address the peculiar needs of different applications. Majorly, these factors will be specific to a type of flawed specimen and the intended use of the flawed specimen. That said, flawed specimens generally fall into three distinct categories: flawed plate specimens, flawed pipe specimens, and flawed tubing specimens. 

Generally, the factors to consider for any flawed specimen include joint designs, material types and grades, code or specification, filler materials, relevant flaws, and welding processes. Also, it is best to design flawed specimens to suit the exact requirements for qualification or training so that the user has the options of size ranges that are suitable for the user’s training needs or their scope of work.

  • Plate flawed specimens – The additional factors to consider for a flawed plate specimen include material thickness range and material curvature. 
  • Piping flawed specimens – The additional factors to consider for a flawed piping specimen include pipe thickness range, pipe diameter range, and components joined. However, the common procedure uses nominal pipe thickness and diameter. 
  • Tubing flawed specimens – The additional factors to consider for flawed tubing specimens includes tube thickness range and tube diameter range.

V. What Types of Flaws are in Ultrasonic Specimens?

These are standard specimens that satisfy the specific factors related to the flaw and its intended use for flawed ultrasonic specimens. Some of these flawed specimens include toe crack, transverse crack (embedded), root crack, sidewall crack, center-line crack (embedded), lack of sidewall fusion, lamination, incomplete penetration (SV), incomplete penetration (DV), porosity, slag, and lack of root fusion.

Other flawed ultrasonic specimen factors include code specification, welding processes, joined components, material type, and size.

VI. What Types of Flaws are in Radiographic Specimens?

The field of flawed specimen manufacturing is full of a wide array of flawed specimens. These specimens include educational kits, specimen sets, custom specimens, and standard, flawed specimens for standard NDT tests. Radiography is a standard NDT testing and, as such, has its standard, flawed specimens. Here are some flawed specimen types used in radiographic NDT testing. Root crack, transverse crack, lack of root fusion, porosity, incomplete penetration, excess penetration, root concavity, slag line, undercut, tungsten inc., mismatch, burn through.

VII. What Types of Flaws in Visual Specimens?

Visual inspection is yet another very popular NDT for inspection of flaws and identification of flaws. The use of visual specimens spans a wide use case and is the first inspection method for most manufacturing before using additional testing methods. Some types of the flawed specimen you will find in visual inspection includes surface porosity, lack of root fusion, root concavity, incomplete penetration. Others include excess penetration, irregular penetration, undercut concave cap, excessive weld spatter, and crater cracks.


So, there you have it, the complete justification for why a flawed specimen is so crucial in non-destructive testing, especially for ultrasonic testing. 

More importantly, their effectiveness in helping NDT personnel identify flaws is a significant benefit. But that’s not all. Also, its cost-effectiveness makes it a preferred option to achieve flaw identification. Other options like on-the-job flaw detection are costly, grossly inaccurate, and often require destroying the sample to ascertain the actual state of defects. Nonetheless, knowing the types of flaw specimens used in different testing situations and the kind of non-destructive testing where they are suitable is often a game-changer.

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