Submerged arc welding (SAW)

Introduction

Submerged arc welding, also known as submerged arc welding, is a process for producing welded joints in which the material to be welded is coated with a metal powder. This powder is applied to the workpiece and heated by an arc generated by the filler metal. The filler metal, often a wire or strip, is passed through the powder to the material. As the powder is heated, it melts to form a layer that protects the weld from the atmosphere. This also prevents the material from cooling down too quickly.

Submerged arc welding is particularly suitable for high-alloy materials such as steel, nickel and titanium, and is therefore mainly used in heavy industry and engineering. It can produce strong and large welds at high loads and temperatures, which is essential for applications in the chemical, oil and gas, and aerospace industries.

However, submerged arc welding has its drawbacks. It is a complex process that requires high levels of operator skill and specialised equipment. It is also an expensive process compared to other welding processes.

Areas of application

Submerged arc welding is mainly used in heavy industry and engineering. Some examples of submerged arc welding applications are

• Chemical and petrochemical industries: used to produce pipes, vessels and apparatus made from high alloy materials such as steel, nickel and titanium, which are exposed to high temperatures and pressures.
• Power generation and plant construction: used to manufacture steam generators, boilers and other plant components from high-alloy materials that are subjected to high temperatures and loads.
• Aerospace: used to make rocket engines and other aerospace components from high-alloy materials such as titanium and nickel.
• Offshore and marine: used to manufacture oil platforms, ships and other marine structures from high-alloy materials.
• Mining and heavy engineering: Submerged arc welding is used to produce bucket wheels, buckets, elevators and other heavy equipment components from high-alloy materials.
• Automotive and Transportation: Used to produce car frames, chassis, suspensions and other components from high-alloy materials.

In all of these applications, the high strength and reliability of the weld is essential, so submerged arc welding is often chosen.

Advantages and disadvantages

Submerged arc welding has both advantages and disadvantages compared to other welding processes:

Advantages:

• High strength: produces strong and tight welds that can withstand high loads and temperatures.
• High reliability: Produces a uniform and homogeneous weld that is less prone to failure.
• Suitable for high alloy materials: Submerged arc welding is particularly suitable for high alloy materials such as steel, nickel and titanium.
• Deep penetration: Allows deep penetration into the workpiece to weld deep layers.

Disadvantages:

• High demands on the welder: Submerged arc welding is a complex process that requires a high level of skill from the welder.
• High cost: It is an expensive process compared to other welding processes.
• Special equipment required: Submerged arc welding requires special equipment and accessories that cannot be used for other welding processes.
• Emissions: Produces emissions that can be harmful to the environment and health.