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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Advantages Of Different NDT Techniques

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For more information about  NDT Techniques visit here: www.globalwelding.com.au

The Working Processes Of A Good Welding Inspector

Welding InspectionA typical welding inspector is entrusted with the task of overseeing each and every activity as well as duty of a welding staff so as to ensure that all things are in ideal working manner. The job of the professional is making sure that welders conduct their tasks within the fixed deadline and quality specifications. It is also important for him or her to possess advanced knowledge about welding processes and procedures in order to be capable of providing guidance in problematic scenarios.

A good welding inspector is also expected to visually assess the welded products in order to check for room to improve or eliminate deformities. They can even utilise stress equipment for putting stress on weld joints. They are responsible for collecting records of readings from tests for future reference. They primarily work in the field of manufacturing processes and building construction.

Let’s take a quick look at the the different duties performed by professionals of welding inspection in Melbourne:

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  • Interpretation of purpose as well as requirements of the various standards, codes and specifications.
  • Making sure that a specific process is available, approved and employed in the production.
  • Verifying the availability of enough legitimate welder approvals, and also making sure that only the approved ones are utilised in production.
  • Checking the parent material against markings and documentation.
  • Inspecting the correctness of different welding consumables like gases, fluxes, filler wires, electrodes, consumable inserts, etc.
  • Inspecting that the fit-up, weld preparations and dimensions are according to the specifications.
  • Verifying that the required preheat complies with the particular procedure.
    Assistance & agreement along with preparation of ITPs or Inspection & Test Plans.
  • Surveillance at the time of welding for ensuring compliance with required procedures like preheat, post heat and interpass temperature control requisites.
  • Inspecting to ensure conduction of post weld heat treatment as per specification requirements.
  • Dimensional check and visual inspection of the completed weld against specification drawings and requirements.
  • Utilising various methods of non destructive testing like magnetic particle, ultrasonic inspection, radiography or liquid penetrant to study their results on a specific welding work.
  • Evaluating and preparing inspection reports for a client or employer.
  • Maintaining each and every record of all inspections that they have carried out.

So, basically, these are the things that comprise the regular working processes of a certified welding inspector in Melbourne or anywhere else in Australia. They play a very important role in ensuring the quality & safety of different manufactured products.

Welding Hazards That Must Be Avoided At All Costs

Although the profession of welding is beneficial in a number of ways like travelling and incentive bonuses, there are several challenges that professional welders have to face quite often in their field of work. And if there is even a slight ignorance of safety hazards, it can trigger a range of hazards like high voltage shocks, suffocation from gas, explosion, fire accidents and so on.

In order to ensure safety in their line of job, there are some specific hazards that welding operators need to avoid no matter what. They have been described below in detail:

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Gases & Fumes

Welding fume consists of malignant compounds of metal oxide from base metal, consumables and base-metal coatings that can trigger serious health problems. Therefore, all the areas in a welding facility must have adequate local exhaust and ventilation to prevent gases & fumes from entering the general space and breathing zone. All operators should also be made to wear approved respirator devices.

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Electric Shock

Perhaps the most immediate and serious potential hazard is the risk of electric shocks. This is because a high voltage shock can lead to injury or even death. Generally, an electric shock results from contact with 2 metal objects having a voltage running between them. The best way to safeguard oneself against these kind of mishaps is by ensuring proper insulation. According to many an expert welding supervisor in Melbourne, it is also essential to wear dry rubber gloves for staying safe from shocks.
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Insufficient Protective Equipment

Personal protective equipment or PPE safeguards welding operators against hazards like arc ray exposure and burns. But there are reckless practices among welders which can lead to mishaps or serious injuries, and they include rolling up pant cuffs or clothing sleeves, not wearing safety goggles, not using boots with proper ankle coverage, and so on. All these habits will have to be ditched for preventing accidents resulting from absence of PPE.

explosions-firesExplosions & Fires

A welding arc can generate so much heat that the spatter and sparks may reach even 35ft away, and this often creates potential fire hazards. In order to prevent fire due to spatter from the arc, the work space should be inspected thoroughly for flammable materials.

Thus, all these hazards must be avoided effectively in order to prevent dangerous accidents from occurring within a welding facility.

Measurement Of Thickness Of Duplex Coatings

For corrosion-resistant coatings, thickness of each single coating is a very important factor for determining quality. And measurement of that thickness is usually obtained by using non-destructive methods. Different kinds of duplex coatings are normally classified as per their measurability. They have been described below in detail:

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  • Those comprised of a zinc-nickel or zinc-iron alloy layer and an organic layer. Due to their high costs, they are usually found on components of automobiles for preventing corrosion entirely.
  • Systems installed on piping like shopping carts, brake lines, certain household appliances having zinc thicknesses of 30 microns or less and organic coating of plastic or paint with thicknesses of 200 microns or less.
  • Hot-dip galvanized steel components having zinc layers denser than 80 microns, paint layers with thickness of over 85 microns and distinguishing iron-zinc diffusion zones. They are generally found in steel construction.
  • Versions having zinc thicknesses from 0 to 10 microns, deposited either in a dip bath or galvanically, and also paint thickness within 150 microns. They are common in vehicle body manufacturing.

As duplex systems combine metallic and organic coatings, the methods used for measuring them involve usage of economical and non-destructive instruments that are easy to handle. Such coating inspection techniques incorporate eddy current and magnetic induction test methods. The latter test procedure is normally performed as per DIN EN ISO 2178 for measuring nonmagnetic coatings primarily applied to iron, steel and other ferrous metals. On the other hand, the eddy current method test is conducted as per the DIN EN ISO 2360 to measure non-conductive, non-magnetic coatings on various non-ferrous metals.

Eddy current method, which is phase sensitive, necessitates the metal coating to have significant electrical conductivity so that the current can actually develop. However, zinc coatings often exhibit lesser electrical conductivity of below 1MS/m due to having crystalline structure. For carrying out thickness measurement on basis of phase measurement, frequencies above 10 MHz are used.

In general, large components present within practical measurement amalgamate magnetic induction with phase sensitive eddy current. With extra action input from the operator, the measurements are performed using both methods successively after placing a probe. After that, the data of the measurement is collected suitably.

Thus, these are the industrial processes used for measuring thickness of duplex coatings. The above explanation is a simple demonstration of the methods involved. If you want to know more about them, look up informative articles over the Internet or get in touch with an expert.

Why Is Visual Welding Inspection Important?

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From time to time, scientists and the welding industry have devised several methods for inspecting the quality of welds after their completion, such as ultrasonic testing, radiography, magnetic particle testing, liquid penetration and so on. Despite of the fact that these techniques are highly advanced and substantially effective at detecting flaws, there are still plenty of manufacturing firms throughout Victoria (and also Australia) that rely heavily on the traditional visual welding inspection technique.

Even in the modern times, the significance of a good old visual welding inspection cannot be ignored. In order to carry out the analysis, a qualified welding inspector usually remains present during the operation. It is his responsibility to make sure that standard quality welds are achieved, particularly by investigating condition of the electrodes, relevant certificates, weather condition, joint preparation, tools & machines used, slag cleaning, current, incomplete welds, etc. These steps cannot be assessed properly without thorough scrutiny by the human eye.

A typical visual welding inspection in Melbourne can help to save a lot when conducted properly, by nullifying the need for re-radiography and repairs. But in order to make that happen, the inspector taking care of the process requires to pay careful attention to every aspect. However, that is generally not a problem because most reputed welding inspectors possess the required qualifications and certification issued by the relevant authority. They are also aware of the necessary international & national standards and codes that they need to observe. For instance, pipeline welds are generally inspected as per API 1104 and so on.

Another vital reason why visual welding inspection has such substantial significance in the manufacturing industry is due to the fact that not all joints are picked for radiography once they have been completed. And any joint not inspected by radiography may have a flaw, which can cause a pipeline or plant operation to fail, ultimately spelling disaster. A faulty joint is incapable of handling the stress triggered by high temperature and pressure of the fluid inside it. But a joint that has been inspected visually is already flawless and can therefore, pose no threat even if not selected for radiographic testing.

Thus, it is clearly evident from the above mentioned information why visual welding inspection is given so much importance even today. Its efficacy cannot be championed even by uber-modern techniques like magnetic particle testing or dye penetration. It can stop weld defects even before they occur.