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.

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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.