What are the properties of offshore engineering steel, and how do they differ from other types of steel?

TAGS: offshore | steel | engineering |

Steel for marine engineering has the following characteristics:

Corrosion resistance: The marine environment contains seawater, salt and other chemicals, so steel for marine engineering needs to have good corrosion resistance. This is usually achieved through the use of special alloying elements or coatings.

Strength and hardness: Steel for marine engineering needs to have sufficient strength and hardness to withstand forces such as seawater pressure, shock and vibration.

Weldability: Since steels for marine engineering often need to be welded, they need to have good weldability, including good plasticity and toughness.

Tensile resistance: Steel for marine engineering needs to have high tensile properties to withstand external forces such as waves and wind.

Compared with other steel types, steel for marine engineering has the following differences:

Alloy composition: Steels for marine engineering usually contain more alloying elements, such as nickel, molybdenum, titanium, etc., to improve their corrosion resistance and strength. For example, seawater contains a large amount of chloride ions, which will corrode the surface of ordinary steel and form rust spots, while the corrosion resistance of steel for marine engineering can be improved by adding elements such as nickel and molybdenum.

Alloying degree: The alloying degree of marine engineering steel is usually higher than that of ordinary steel, and can reach P90 level (that is, more than 90% martensite content). This high degree of alloying increases the strength and hardness of the steel and makes it harder to corrode.

Tensile strength: The tensile strength requirement of marine engineering steel is usually higher than that of ordinary steel. For example, in the construction of offshore drilling platforms, the steel pipes used need to have a strong tensile capacity that can withstand up to 600 megapascals (MPa).

The following are some common marine engineering steels and their main parameters:

Material	Tensile strength (MPa)	Yield strength (MPa)	Elongation (%)	Alloy content (wt%)
AH363D	105-125	78-85	20-25	0-2.5
316L	100-120	55-65	20-25	10-18
347H	105-120	78-85	20-25	0-2.5
416L	105-120	78-85	20-25	0-2.5

It should be noted that the above data are for reference only, and appropriate materials should be selected according to specific conditions in actual applications.