Defining Forensic Engineering And Failure Analysis

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Failure analysis on a metal is performed by systematic examining, analyzing and testing the failure or flaw, gathering information about the application, component and history, which is further followed by a detailed visual examination. Failure analysis is a part of nondestructive testing which is scientifically known as magnetic particle testing, dye penetrant testing, low magnification, etc. High magnification examination and destructive testing is also sometimes applied like, sectioning the sample for Metallographic micro analysis, Chemical Analysis, Hardness testing, Mechanical testing.

These tests can only performed by a certified welding inspection team in Melbourne.

Macro Examination

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Macroetching is the procedure of etching a sample and evaluating it macro structurally at low magnifications. It is a very frequent technique used for evaluating steel products. There are many different procedures for rating a steel sample by graded series of photographs. The images shows the incidence of certain conditions and is applicable to carbon and low alloy steels.

A number of different etching reagents may also be used depending on the type and process of examination to be applied. You should know that steels react differently to etching reagents because of variations and difference in chemical composition, heat treatment, method of manufacturing and many other factors.

Macro examinations are also performed on a polished and etched cross-section of a welded material. During the testing process, a number of features can be determined including the sequence of weld, weld procedure and qualifications tests. Any defect on the sample can be assessed for compliance with relevant specifications. It can be a slag, lack of weld penetration, porosity, lack of sidewall fusion and poor profile of a weld.

Micro Examination

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Micro examination is performed on specimen either cut to size or mounted in a resin mold. At first they are polished to a fine finish and then etched in an appropriate chemical solution prior to examination on a metallurgical microscope. Micro examination is performed to assess the structure of the material. It is also very common to examine for metallurgical anomalies such as third phase precipitates, excessive grain growth, and various other reasoMicro Examinationns. Many routine tests such as phase counting or grain size determinations are performed in conjunction with micro-examinations.

Forensic engineering and failure analysis of a metal are all high profile examinations, which are conducted to find out even the simplest flaw in a material component.

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Understanding The Difference Between Welding Defects and Discontinuities

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Welding defects and discontinuities can form due to several reasons. This is the reason maintenance is a key factor. But considering the metal components, these complications can still arise. Therefore, to meet the quality of the production, understanding the welding discontinuities and defects is very important. Even though both terms sound similar but they are actually quite different in industrial language.

Welding Discontinuity

Welding Discontinuity

When a material component lacks in physical, mechanical or metallurgical harmony it is called welding discontinuity. Well, this can be demonstrated in terms of:

  • Joint penetration or incomplete fusion
  • Varied porosity
  • Subtle cracks & tears
  • Unacceptable profiles

Welding Defects

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Any developed discontinuity is welding defect. When the discontinuity furnishes a weld incompetent or lowers the quality, it is known as welding defect. Defects increases the risk of using the product which soon meet with major accidents in the industrial workspace.

A Preventive Method

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To prevent such kind of welding defects or discontinuity it is crucial to hire a certified non-destructive testing company in Melbourne. They are experts in understanding the conformity of the material component to prevent major accidents in the long run. Also, they are skilled in performing a range of NDT which includes, coating inspection, AICIP pressure vessel inspection, metallurgical testing and many.

The major differences between discontinuities and defects

  • Well, the definition of discontinuities and defects is depended on the type of industry. However, there are some general explanation to understand the difference between discontinuities and defects.
  • Any weld becomes a defect when a certified welder or the inspection team rejects the welding process and blacklists the product.
  • Before tagging a product as defect the inspection team provide a defined list of acceptable discontinuities with the list of number or type of discontinuities.
  • In the case of a discontinuity it can survive a field test but a defect won’t.
  • If the discontinuities stay within the acceptable production error margin they can be ignored easily, while in the case of defects, they must be repaired. However, if the defect cannot be repaired, the product simply get rejected.

Whether it’s a defect or a discontinuity, it’s important to conduct with an NDT expert to properly understand the differences between a weld defect and discontinuity. Even the simplest imperfection can compromise the quality and safety of the industry.

What Is NDT? Which Is The Most Common NDT Method?

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This blog is all about providing a general information about NDT to people familiar with the process. So what is NDT and what are the techniques applied in it?

NDT stands for Non Destructive Testing, which is a process of evaluating, testing and inspecting different materials and their components. In other words, the part of the machine again becomes useful after conducting this specialised testing.

The test is conducted to determine a material’s physical components like ductility, impact resistance, fracture toughness, fatigue strength, and tensile strength.

Different NDT methods and their benefits

There are various types of NDT methods. Some of the common ones are Magnetic Particle Testing, Electromagnetic Testing, Guided Wave Testing and many more. Each of the techniques are conducted on different applications with various advantages. The tests are a form of solution to upgrade industrial environment and provide commercial independence.

The most common method of NDT

1.Welding Corrosion Testing  is one of the most common methods of non destructive testing. Welding inspection is further categorised into two forms, Radiographic Testing and Ultrasonic Testing. Obviously, these tests are conducted to determine the internal integrity of a weld without destroying the welded component. Let’s take a deeper look into these specialised tests.

2. Radiographic Testing – In this method X-rays are used from a tube which is X shaped. In some cases, gamma rays are also used from a radioactive isotope. The main objective of radiographic testing is similar to medical radiography. In this case, rather than passing the penetrative radiation through human body, it is passed through a solid object on a photographic film. The photographic film is the final image of an object’s internal structure. If the image appears whitish, it means the body of the object is thin or porous. On the contrary, if an image appears dark, it means that the walls of the object are at their best quality. In actual, an object’s thickness and density depend upon the amount of energy (radiation) absorbed.

3. Ultrasonic Testing – In this method, mechanical vibrations are used which are similar to sound waves in a high frequency. A beam of ultrasonic energy is passed through an object without damaging it. If the energy reflects it means it is a cause of discontinuity.

Thus, radiographic and ultrasonic testing are simplified.

The advantages of NDT are enormous when the quality and productivity are considered. After conducting all these tests, manufactured items are considered safe and legal.