Best Known Welding Methods From Experts Around The Globe

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Welding is a sculptural process of binding and joining metals or thermoplastics by causing fusion. Welding melts the base metal and a filler material is typically added to the joints to form a pool of molten material. This molten metal then cools down to form a joint.

There are different methods for welding and each has its own pros and cons. For example, there are less common methods for welding processes such as friction welding in which the base metal does not melt.

Some mostly used welding methods as revealed by the experts in non-destructive testing are:

  • Oxy-fuel welding – This method is also known as oxyacetylene welding or oxy-welding in short. It uses fuel gas and oxygen to weld and cut metals.

  • Shielded metal arc welding – Better known as ‘stick’ or ‘electric’ welding, this method uses a flux coated electrode. The electrode holder holds the electrode as it slowly melts away.

  • Gas tungsten arc welding – Also known as TIG, this one uses a non-consumable tungsten electrode to produce the weld. The welded area is protected from atmospheric contamination by an inert shielding gas such as argon or helium.

  • Gas metal arc welding – Mostly termed as MIG, it uses a wire feeding gun that feeds wire at an adjustable speed and flows an argon-based shielding gas or a mix of argon and carbon dioxide over the weld puddle to protect it from atmospheric contamination.

  • Flux-cored arc welding – Almost same as MIG except the fact that it uses a special tubular wire filled with flux. It can be used with or without shielding gas, depending on the filler.

  • Submerged arc welding – This method uses an automatically fed consumable electrode and a blanket of granular fusible flux. The molten weld and the arc zone are protected from atmospheric contamination by being “submerged” under the flux blanket.

  • Electroslag welding – This one is a highly productive method using single pass welding process for thicker materials between 1 inch and 12 inches in a close to vertical position.

There are a number of companies providing services for welding inspection, welding supervision and non-destructive testing (NDT). Inspection is readily necessary after the job is done and should not be left out, since it might prove to be dangerous afterwards.

Important Questions To Consider While Certifying Your Welders

 

Important Questions To Consider While

If you want to enhance your business profits and establish a reputation in the market you should definitely certify your welders to provide quality services. A team of well trained NDT personnels means great achievement in the field of testing and welding. However, there are several questions that often appear when it comes to getting certified from a certifying board.

So, here are some to make the process easier:

Can an employer choose a particular welding inspector who has previously obtained recognition from Regulatory Authorities?

It is the right of an employer or owner to employ whoever they wish to. They just need to comply with the appropriate standards and regulations proposed by the government. AICIP offers them the opportunity to utilise a nationally recognised, independent certification program to make decisions and assist the responsibilities properly to become a competent person.

Does AICIP insist on mandatory training requirements for a particular field?

No, AICIP has no prerequisites for anyone who wishes to apply for an examination. AICIP has produced a list of competencies for novice inspectors on which the questions are set. It does not have any mandatory requirement.

What is the rough estimate of the examination cost?

The cost of the examination fees is based on the anticipated number of candidates
and conducting the examinations on a national basis. AICIP is independent of all government funding agencies and solely relies on sponsorship to administer the examination.

Will certificates of competency licences be recognised for exemption from AICIP examinations?

AICIP has not been able to confidently state that a person is competent enough based on the wide range and diversity of documents put forward for exemptions. AICIP has not found such a solution for in-service inspectors and thus, has decided that all candidates seeking certification must undertake the examinations.

However, if a person is certified for welding corrosion testing from a foreign country, mutual recognition agreements occur between AICIP and that specific certifying board takes the final decision.

Can a person sit for the Senior Inspector Level without applying for the In-Service Inspector Level?

Candidates must complete the basic In-service Inspector Level before proceeding to the Senior Inspector Level.

When does a re-Certification take effect?

Re-certification becomes a necessity 5 years after examination.

If you want to train your employees to deliver the best services in Melbourne, hire a certified NDT expert who provide all kinds of NDT training.

Weld Evaluation Of Camshafts Using Ultrasonic Testing

Generally, ultrasonic testing (UT) is used to figure out the quality of brazed joints. With the help of this unique process, evaluating brazing quality becomes simple. It uses a focused transducer, and ultrasonic waves along the radius of the shaft are focused on the brazed joint. By monitoring the amplitude of the echoes returning from the joint position, one can evaluate the brazing quality easily.

When the echo becomes weak, it indicates a strong bond where most of the ultrasonic waves travel through the joint. On the other hand, a strong echo means that there is no mechanical bonding, causing the ultrasonic waves to bounce back at the interface. A reference sample with a known unbonded area can be used to set the ultrasonic machine sensitivity and evaluate the amount or percentage of any flaw in the part.

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Camshafts

Camshafts are typically manufactured by machining cast iron, forged steel or billets down to the desired shape. Some manufacturers have started to produce camshafts by joining cams to shafts with a brazed joint. Due to the force being potentially applied to the brazed joint, quality control is required to ensure brazing quality and that a sufficient percentage of cam is solidly brazed to the shaft. Ultrasonic testing must be conducted only through experts who provide certified non destructive testing in Melbourne.

Camshaft geometry

A camshaft is basically a shaft with cams distributed along its length. Cams can come in different shapes with one common characteristic: there is at least one protuberance found along the circumference, resulting in an irregular shape. A common model is a cam with a nose (lobe), where the brazed joint is not parallel to the outer surface. In such a situation, there is little to no probability of recording an echo from the joint; this is what will be referred to as the uninspectable area of a cam.

Brazed joint evaluation

It is not always necessary to inspect each individual part of the camshaft to control the quality of a production. A statistical analysis can be performed on sampled parts taken from the production line. The same logic applies to the uninspectable area of the cams; a statistical analysis can still be performed by monitoring the percentage of good brazing within the inspectable portion of the cams. When using ultrasounds to monitor the brazed joint quality, the evaluation must be normalized to ratio of inspectable area.

As ultrasonic testing is sensitive to both surface and sub-surface discontinuities, be sure to hire the certified personnel to figure out the flaws properly and end on a positive note.

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.

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:

Welding Inspection

  • 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.

Advantages Of Different NDT Techniques

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As most of us know, NDT or nondestructive testing is a procedure mainly utilised to inspect, evaluate or test various assemblies, components or materials for differences in their characteristics or discontinuities, without damaging the functionality of the system or part. In the modern world, they are used as a part of fabrication, in-service and manufacturing inspections for ensuring product quality & integrity. In this blog, we are going to talk about the major advantages of some common non destructive testing methods:

Ultrasonics – used for measuring velocity & density or detecting internal variations & defects.

  • High sensitivity to cracks
  • Very portable
  • Automation possible
  • Permanent records
  • Produces results immediately
  • High penetration

Infrared Thermography – effectively detects or measures heat transfer, electrical assemblies, temperature ranges, hot spots and temperature monitoring.

  • Thermal picture/permanent record
  • Decently portable
  • Remote sensing

Eddy Current – mainly used for detecting surface as well as subsurface seams & cracks.

  • Economical
  • Does not necessitate couplant
  • Probe contact is not required
  • Very fast
  • Permanent records

Liquid Penetrant – can find cracks, seams, laps & porosity, and even move through leaks in walls.

  • Cost effective
  • Indications can be evaluated further
  • Portable

Magnetic Particle – helps to find cracks, inclusions, seams and defects; can also detect really tight cracks.

  • Subsurface flaw detection
  • Affordable
  • Significantly portable

Radiographic Testing – aids in detecting or measuring internal variations & defects, inclusions, deficiency of fusion, porosity, corrosion, density changes, geometry variation, misaligned and misassembled components.

  • Geometry variation has no effect on the pathway of radiation
  • Permanent records
  • Portable

Resonant Inspection – can detect shifts in resonant frequency resulting from alterations in mass, damping or stiffness of a certain component. Flaws like voids, chips, cracks, nodularity, brazing problems, hardness variations, porosity, skipped manufacturing process & delamination are detectable with resonant inspection too.

  • No need to spend anything on consumables
  • Can be automated easily
  • 3 seconds/part
  • Permanent records
  • Whole compotent test for external and internal flaws
  • Designed for being on plant floor
  • Best for quality inspection of high volumes
  • No need for preparation of the particles
  • Objective result

Thus, if you need to make informed decision about which NDT method would be best for inspection of your products, refer to the pros of the ones mentioned above.

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.