Magnetically Impelled Arc Butt (MIAB) Welding

Introduction

Magnetically impelled arc butt (MIAB) welding (also known as rotating arc welding). MIAB is a forged welding process for joining pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. Forging is a method of shaping metal through hammering, pressing, or rolling. This welding process relies on an electric arc to generate the necessary heating to melt the surfaces being welded. MIAB welding is an advanced type of welding process that is a replacement for general welding processes such as friction, resistance, and butt welding. It is a type of solid-state welding process used for tubes and pipes in which heat is generated through an electric arc. MIAB has been developed since the 1970s. MIAB welding was developed for welding non-ferrous metals like aluminum and copper as compared to conventional welding processes.

In the MIAB welding process, the two components that are to be welded are clamped in MIAB welding equipment with a small gap between both ends. In the first step, a direct current (DC) arc is kept between the component ends. Then a radial magnetic field causes this arc to travel around the joint circumference at high speed. heating continues and in the second step, heating continues for a few seconds then, in the second stage, the components are joined together at a forging pressure  Any molten material is expelled from the joint, and as a result, a solid phase weld is produced. The components remain fixed they do not rotate during the whole welding process. There is a good thing in MIAB, no filler metal or shielding is required, and as a by-product, it only produces a little fume. Example of MIAB welding is low and medium carbon steel and low alloy steel etc. MIAB welding has many applications such as: in the production of drive shafts, propeller shafts, beam axles, axle casings, and refrigerator condenser tubes. MIAB welding process is used in the United Kingdom and Germany for welding tubular sections in automobile industries. Advanced MAIB welding has brought a revolutionary change in the automotive industry nowadays.

Working Principle

MIAB welding is a type of solid-state welding. Its process involves the rotation of the arc around the tube to help the uniform heating of faying surfaces (two mating surfaces that are to be joined).  The tubes which are to be welded together are aligned together by clamping arrangement and the external constant magnetic field is applied in the weld area. And heat is generated in the faying edges through electrical discharge and rotation of the arc by application of the external magnetic field. After required heating, the tubes are forged (pressed) to expel the molten metal and other impurities from the faying surface resulting in a solid state joining of tubes. After this, the welded parts are rapidly brought under pressure.

Properties of MIAB welding

MIAB welding process is a simple, cheap, and less time taking process, it is a single-shot process and doesn’t require any manual skill and could be easily performed automatically. Its welding time of 22 seconds for a pipe of thickness 6 mm which is quick and fast. It produces a solid-state bonding after welding which have excellent mechanical properties. It also opens up the possibility of dissimilar metal joints. It has many advantages; it has a less internal flash, shorter weld time, less metal loss, less expensive, low operating current, uniform heating, and less or no machine maintenance. It does not involve rotation of either component (therefore it overcomes problems with asymmetrical parts that occur with friction welding processes).

Relationship Between Parameters in MIAB welding 

In MIAB welding, the arc rotation speed is dependent on four main parameters. These four parameters include 1-welding current, 2-Arc voltage, 3-magnetic coil voltage, and 4-magnetic coil current. Where the arc speed varies linearly along with welding current and voltage in a plot.  From the experimentation, it is clear that welding current has more impact on arc speed than the remaining three parameters. The performance analysis shows that the welding current controls the arc speed more than the welding input voltage. Whereas, the magnetic coil current and voltage have very less or no impact on the arc speed.

Applications of MIAB Welding

MIAB welding has many benefits over other welding types. MIAB welding is free of rotation of any component hence there is no chance of fiction issues. It is a quick or less time-taking process. It is a loss-free method, there is low or no material loss involved. It is safer than other methods as it produces low fumes and spatter. MIAB welding requires a relatively low required arc current in the whole process. MIAB welding uses an electric arc for heating near joints instead of other welding processes that use resistance to accomplish heating. MIAB is considered a non-consumable electrode arc welding process, that preserves the welding parts and does not consume them in the process instead it uses electrode arc for this purpose. There are many applications of MIAB welding that are listed below:

1. It is used for welding thin-walled tube
2. Butt and T-butt welding are used to join automobile parts
3. It is used for thick-walled tubes welding
4. It is also used for welding solid parts
5. It is used for welding tubes in plate welding and flange welding
6. It is used in pipe and tube assemblies and shock absorber assemblies
7. It is used in Vehicle driveshafts
8. It is used in  brake pipes
9. It has other applications in the power, automobile, defense, oil, and gas sectors

FAQs

What are the applications of MIAB welding?

MIAB welding stands for Magnetic Induction Arc Butt welding, is a process used to join two metal parts together by heating them with an electrical arc that is generated by induction. It is typically used to join pipes and tubes made of materials such as stainless steel, aluminum, and copper.

What are the stages of MIAB welding?

The stages of MIAB welding include:

• Preparing the parts to be welded by cleaning, aligning, and clamping them in place
• Applying a magnetic field to the parts to be welded
• Passing an electric current through the parts, which generates an arc that melts the surfaces of the parts
• Applying pressure to the parts to fuse them together as they cool

What precautions should be taken during welding?

Precautions that should be taken during welding include:

• Using appropriate personal protective equipment (PPE) such as a welding helmet, gloves, and protective clothing
• Ensuring proper ventilation to remove hazardous fumes
• Maintaining a clean and well-organized work area
• Following proper procedures for storing and handling flammable materials
• Never welding in areas where there may be flammable gases or liquids
• Being aware of the fire hazards associated with welding, and having fire extinguishers readily available
• Following proper procedures for shutting down and disconnecting equipment before performing maintenance or repairs
• Keeping a safe distance from the welding arc to prevent burns, and avoiding looking directly at the arc
• Avoiding welding on painted or coated surfaces, as the heat can cause toxic fumes
• Avoiding improper use of welding equipment

What checks must be made before welding?

Before welding, the following checks must be made:

• Check that the welding equipment is in good working condition and properly grounded
• Check that the work area is clean and well-organized
• Check that the materials to be welded are clean and properly aligned
• Check that all necessary personal protective equipment (PPE) is available and in good condition

 What PPE is needed for welding?

Personal Protective Equipment (PPE) needed for welding includes a welding helmet, gloves, protective clothing, safety glasses, and ear protection.

What is the first inspection done to a weld?

The first inspection done to a weld is called a visual inspection, which is performed to evaluate the quality of the weld and identify any defects such as cracking, porosity, or lack of penetration.

What is the most commonly used method of weld inspection?

The most commonly used method of weld inspection is radiographic inspection, which uses x-rays or gamma rays to examine the internal structure of a weld.

What are three commonly used codes in welding?

Three commonly used codes in welding are American Welding Society (AWS), American Society of Mechanical Engineers (ASME), and International Organization for Standardization (ISO).

Why laser welding is used only for micro welding applications?

Laser welding is used only for micro welding applications because it uses a focused laser beam to generate high heat and melt the metal at a very small and precise point, making it suitable for welding small and delicate parts or precision joining of thin sheets. It is less suited for large and heavy components or the joining of thick materials.

Conclusion

There are many types of welding using different types of processes i.e., resistance, friction, and percussion. MIAB welding is a type that uses an electric arc to accomplish heating at the joint, unlike other types that use resistance. Hence it is a type of arc welding process rather than resistance welding.  It is also known as rotating arc welding. It is a non-consumable electrode arc process, as it uses the electrodes that consume, and the parts being welded are preserved. It is a cheap, less expensive, less time-taking process, and has many applications as compared to other types of welding.