Correct welding processes in shipbuilding

Ship hulls are constructed from hundreds of sheets of metal, and good ship welding during the shipbuilding process is crucial to ensure that they have the right shape and strength. In fact, welding accounts for between 3 % and 5 % of the total weight of a ship, which can amount to between 700 and 1150 tonnes on a 270-metre gas tanker, to give an example.

The most commonly used types of welding

It is of great importance to weld ships with the proper technique. A simple excess of heat applied could weaken the mechanical properties of the steel, leading to structural damage later on. Equally relevant is the choice of the correct welding process, based on the material and the desired design of the project. Thus, there are the following types of welding for ships.

Gas shielded arc welding

Arc welding using a solid or tubular electrode with a continuous consumable feed. The molten zone and the arc are protected from atmospheric contamination by a flux blanket composed of various oxides and compounds. This method allows for high current intensities (200–2000A) and is widely used in shipbuilding.

Submerged arc welding

Performed with a bare electrode and granulated flux. Part of the flux melts while the rest is reused. It‘s fast, automatable, and cost-effective for sheets thicker than 6 mm—common in shipbuilding.

Plasma Arc Welding (PAW)

Based on TIG welding, but reaching up to 28,000 °C. Uses a central plasma gas to melt the base metal and an annular gas for protection. Allows welding of thicker parts.

Oxyacetylene welding

Uses a flame of 3500 °C to weld by combustion (autogenous welding), with or without material input. Used for thin plates or intricate pipelines.

Manual welding with coated electrodes

The most widely known process. Involves an electric arc between the electrode and base metal, melting both. Requires high skill for proper application. Effective for almost all metals and thicknesses.

Semi-automatic continuous wire welding (MIG/MAG)

Shielding gas and filler material are applied together. Uses a consumable wire as electrode. MIG uses inert gas; MAG uses active gas. Offers 80–95% efficiency and is used for hulls, aluminium, stainless steel, and other alloy structures.

TIG Welding (Tungsten Inert Gas)

Employs a tungsten electrode (melting point ~3400 °C) with or without filler material. Uses helium, argon, or a mix as shielding gas. Known for high penetration and quality. Suitable for stainless steel, nickel alloys, titanium, aluminium, etc.

Thanks to the development of all these techniques, it is now even possible to carry out ship welding underwater. If your vessel needs welding, Suisca Group will put you in touch with expert companies in the relevant sector. With over 30 years dedicated to providing a comprehensive service in ports, we will provide professional ship welders with a proven track record to ensure that the results will be totally safe and of the highest quality. Suisca Group offers everything you could possibly need for a vessel in your port of call!