Laser Beam Welding (LBW) consists of minimum heat affected zone (HAZ) among the given welding processes. This means that the LBW process produces less distortion, less residual stress, and less change in the microstructure of the material being welded.

Explanation:

Heat affected zone (HAZ) is the area in the vicinity of a weld where the base material has undergone a change in its microstructure and properties due to the heat input from the welding process. The size of the HAZ depends on the welding process, the welding parameters, and the material being welded. A large HAZ can cause distortion, cracking, and other defects in the welded joint.

Among the given welding processes, LBW uses a highly focused laser beam to melt and join the base material. The laser beam has a very small diameter (typically less than 0.5 mm) and a high power density, which allows it to rapidly heat and melt the material in a localized area. This results in a very small HAZ, typically less than 0.1 mm.

Advantages of LBW:

• Minimal distortion: the small HAZ reduces the amount of distortion in the welded joint, making it more accurate and precise.

• High welding speed: LBW can weld at high speeds, making it suitable for mass production and automation.

• High quality welds: LBW produces high-quality welds with minimal defects, such as porosity, cracking, or incomplete fusion.

• Suitable for a wide range of materials: LBW can weld a variety of materials, including metals, plastics, and composites.

• Non-contact process: LBW is a non-contact process, which means that the laser beam does not touch the material, reducing the risk of contamination or damage.

• Versatility: LBW can be used for welding, cutting, drilling, and surface treatment, making it a versatile process.

Conclusion:

LBW is a highly efficient and precise welding process that offers many advantages over other welding processes, particularly in terms of HAZ. Its ability to produce high-quality welds with minimal distortion and defects makes it a popular choice in many industries, including aerospace, automotive, and medical.