Best Known Welding Methods From Experts Around The Globe

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.

How Important Is The Job of A Welding Inspector?

Welding examination isn’t something that can be considered lightly. There can be lives relying upon the precision of the investigation. Defective welds that lead to the death or property loss make it to the news all the time. These defects now and then are blamed on specialists of welding inspection. In the event that the assessor had done his activity legitimately, the destructive occasion could have been dodged. This claim sometimes is legitimate; assessors commit errors simply like some other individual in the creation chain. Be that as it may, a reviewer can’t examine quality into the item. The nature of a weldment must be set up at the earliest point of the venture & finished to the end. In the event that any progression in the activity isn’t built up and completed with quality as the most important requirement, the likelihood of defect exists.

In years past, poor welds caused numerous more disastrous disappointments than happen today. Boilers detonated, ships sank, structures and extensions crumbled, and pipelines exploded as often as possible. These calamities wound up far less successive as codes and norms were built up.

One of the principal things an examiner must know is which code or standard ought to be utilized for the examination criteria—both the code of development and the code to qualify the welding methods and welders. These necessities must be sketched out in job specifications. The overseer ought not make presumptions or depend on his judgment for setting the standard. In the event that it isn’t mentioned in the determinations or on the illustrations, the overseer ought not continue without proper clarification.

Prior to any welding, an inspector must confirm that the welding methodology are in consistence with the material standard or code. At times, a client builds up a standard that isn’t referenced to a specific code. This is frequently the case with vast organisations. In these cases, the client standard wins.

The welding assessor must check that the welders are qualified and confirmed to the correct code or standard. Welder capability is built up by testing. A welder who effectively plays out a test and gets an accreditation report is called a confirmed welder. The inspector may need a welder to play out an exhibition for a sensible reason, for example, numerous defects & poor workmanship.

Material traceability stands as an outright need for all tasks. On the off chance that a defect happens and responsibility is included, verification of material quality can explain the reason for it. The examiner can just prescribe certain extra tests to guarantee that the material is of adequate quality for utilization.

Defining Forensic Engineering And Failure Analysis

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

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

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.

Understanding The Difference Between Welding Defects and Discontinuities

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

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

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

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.

Defining Coating Inspection & Its Need

In the field of manufacturing, you already know how important it is to follow the correct sequence of different operations in every aspect. There are various types of coating inspections which fall in the category of NDT services. These processes are executed by highly skilled and trained personnel to read the classification and efficiency of the material. The techniques that are included in the inspections are typically based on different welding codes like, ISO, ASME, API, EN and Australian Standard.

Before conducting any coating inspections, magnetic particle and liquid penetrant testing are done. However, this depends on the type of composition of the materials and the achievement the owner is looking for.

What is the need for coating inspection?

Coating inspection is typically used to figure out ductility, hardness and tensile strength involving the parts that take most of the stress. Thus, without breaking or damaging the material, with the help of NDT, it becomes easy to determine the breaking point. This means that prevention of major accidents becomes easy while maintaining a safe working ground.

Inspection procedure

The procedures of coating inspection include electromagnetic waves, used to gauge the thickness of a specific coating, and measuring the heat distribution (thermography) of the substance. This process determines the quality of the coating (binding to its substrate).

Also, lasers are used to measure the profile of the surface without physically harming the substrate. In the industry of coating inspection, sometimes the use of permanent base coating helps to determine the ductility of the material. The applied coating itself fluoresces under a black light. This allows inspectors to determine the imperfections in the base quite easily.

Gauges and industrial coatings

Various electronic gauges are the most significant contribution to the field of coating inspections. These equipment nowadays are standard inspection devices for quality assurance and control in the industry. These tools are also capable of performing other functions like, ultrasonic waves to figure out the dry film thickness of an applied coating.

The importance

Coating inspection is one of the most important sections in the field of NDT. To protect the superiority of the material, accurate measuring is important, which can only be done through qualified inspectors in Melbourne. They precisely allow the industry to perform as per the mentioned specifications to avoid forensic complications.

Before hiring any NDT company, it’s crucial to check whether or not they are qualified from the WTA and perform any documentation service for inexperienced welders.

Important Questions To Consider While Certifying Your Welders

 

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.

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.

Professional Welding Inspection Services

Advantages Of Different NDT Techniques

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

Significance of Pressure Vessel Inspection

A pressure vessel contains fluids under intense pressure or vacuum. Due to this feature, a pressure vessel can be potentially dangerous if it fails. There are authorised inspectors for pressure vessels who specify any faults to ensure that the units are safe for use. Pressure vessel inspection is a detailed review of the same to assure that it complies with the technical standards.

Pressure Vessels can be dangerous if faulty

The massive expansion of energy released from a pressure vessel can cause devastating damage. Even a simple compressed air cylinder can claim lives if it explodes. But do you know that pressure vessels are everywhere in our daily life? From refineries to mineral processing plants, dry cleaners, wineries, hospitals, your local tire dealer and even the pressure cooker all fall in the category of pressure vessels. They just differ in size and functionality but have the same working procedures.
However, heavy duty industrial pressure vessels are very complex processing structures. They may weigh hundreds of tons and are connected to a variety of pipelines, other pressure vessels and boilers. AICIP pressure vessel inspector in Melbourne can help you to detect faults in such intricate heavy machineries.

Now, what is AICIP?

AICIP is a non profit organisation in the field of Australian Institute for the Certification of Inspection Personnel. It is a body which certifies NDT inspectors so that they can have the appropriate authorisation to conduct the inspection job. It is incorporated with the Department of Fair Trading (a NSW Consumer Protection Agency) under the Associations Incorporation Act 1984. It has Australian Registered Body status with the Australian Securities Commission.

Manufacturing Pressure Vessels to comply with standards

At the manufacturing phase, it is essential that an experienced pressure vessel designer produces a suitable design. The manufactured vessel must then be inspected through an inspector to determine correct fabrication and welding. For the production purpose, the vessel inspector figures out the manufacturing and load taking capability of the vessel.
The qualified AICIP inspector verifies the entire process as per the Australian standards. It is the inspector’s responsibility to determine future faults of a welding or the material itself. This is why it is recommended to hire an inspection team to work as per the legal requirements and caring for your employees.
For designing and inspecting the volume and pressure, the processes and types of product under pressure are all considered to determine hazard level of the pressure vessel.

Pressure vessel inspection is a crucial part of an industry dealing with heavy duty machineries. If you haven’t made such a consideration yet, call an AICIP certified inspector right away to carry on your business safely.