The latest trends in Welding technologies – its future and prospects
It is a method used for fusing metallic materials with the application of heat. Generally, materials like thermoplastics and metals are fused at high temperatures. The workpieces (materials that are used for the joining process) are melted and fillers are included in the fusing points to form a weld pool. The weld pool solidifies to form a well-built point at the junction of the two workpieces. Welding can be classified into many methods depending upon the workpieces. The types include – Arc Welding, Gas Welding, Resistance Welding, Energy Beam Welding, and Solid-State Welding. The usage of lasers, electricity, and high-temperature flame vary under each type.
The advancement in welding technologies started in the time of the industrial revolution. In those days, a process called forge welding was introduced where the ends of the material are heated and hammered at high temperatures. Applications like friction, laser welding, and inertia have helped in improving welding technologies.
LASER WELDING
This process requires a high welding speed. The beam is not allowed to penetrate the material; it can only be absorbed in the surface. It is usually done at higher power densities ranging from 105 W/cm^2. The beam is focussed on a spot with a collimator lens to create a density of 107 W/cm^2. A ‘keyhole’ cavity is formed after the heat gets absorbed in the workpiece. This method of welding is also used for plastics. There are three types of lasers used in a laser welding process namely – Gas, Solid-state, and fiber lasers. Optical fibers play an important role in the laser welding process. Single optical fibers and multiple optical fibers help in increasing the strength of the laser beam. Butt, Filler Lap, Overlap, and Edge Flange Weld are the weld joints used.
- Heat conduction welding – This is used for welds that do not require high strength. In this process, the surface of the metal is heated to form a smooth weld material. A power density less than 500W is used for this method.
- Keyhole welding – In this method.], the heat from the laser beam vaporizes the contact surface into metal. A plasma condition is created at a temperature above 10,000K.
- It is an easily automated welding process.
- No use of electrodes.
- It is highly target-specific.
FRICTIONAL WELDING
It works by the process of friction generated between the two materials, which in turn produces heat and helps in the fusion of the workpieces with external pressure and thermomechanical treatment. There are many applications which include the use of frictional welding in aerospace and automobile industries, for manufacturing components like gears, drill bits, connecting rods, and axles, in hydraulic equipment like welding pump shafts, and electronic industries for welding copper.
- Continuous induce welding – The working principle is based on a rotor and a band brake.
- Inertia Welding – The principle involves an engine and shaft flywheel. Both the engine and shaft flywheels separate from each other when the speed limit is attained by the engine. This stops the brake and the weld is formed by the continuous pressure created.
- It is an eco-friendly process.
- No requirement for any filler metal.
- Strong welding strength is attained.
- It can be automated easily.
- It works with a high welding speed.
- It is highly efficient.
ARC WELDING
This process involves the use of the electric current in the welding process. The use of gas shields and flux helps in enhancing the welding process.
- Metal welding – It can be done at a low temperature and a consumable coated elected is used for the welding process.
- Carbon welding – It is done with the help of two carbon electrodes.
- Gas tungsten welding – A non-consumable electrode is used in this process.
- Submerged welding – A layer of flux is submerged in the electrode and the welding process is initiated.
- The rate of deposition is quite high.
- The wire consumption is significantly low.
- The electrical energy consumption is also low.
- Material of any length can be customized and welded.
- The welds are created with no slag inclusions.
Tremendous advancements have been experienced in the welding industry to enhance their environmental workability and to improve their international competitiveness and it has witnessed a slow and a steady growth phase across the years.