Since its invention more than a century ago, stainless steel has become indispensable in virtually every industry, with different types, categories, and grades, developed for applications unheard of just a few decades ago.
Special Metal Alloys has been supplying nickel alloys and marine-grade stainless steel in the global metal markets for over 35 years.
Contact us online, or give us a quick call on +44 [0]161 278 2386 to find out more.
To create stainless steel, minerals and metals such as chromium, molybdenum, aluminium, copper, nickel, titanium, carbon, nitrogen, phosphorus, and selenium, are alloyed with steel in different ratios to achieve distinctive qualities required for dedicated purposes.
Very few metals can withstand the constant attack of fresh and salt water, moist air, and seawater for long. Even most grades of stainless steel may still underperform under harsh marine conditions.
Marine-grade stainless steel is a superior alloy of different grades and prices, but all with exceptional corrosion and rust resistance, strength, and ruggedness, developed specifically for severe conditions near water, at sea, and on the coast.
High levels of chromium and molybdenum, in particular, shield marine-grade stainless steel from salt, chloride ions, bromides, iodides, and oxides, thus preventing rust from forming.
Marine-grade stainless steel can be welded and finished, making it suitable for fabrication, structural purposes, and ornamentation.
Concentrations of corrosive substances vary according to exposure and evaporation of the water. The greater the severity of the attack, the higher the grade of stainless steel that will be required.
As an example, concentrations of chlorides will be higher in splash zones and the underside of overhangs, where the water evaporates, leaving the salts behind, whereas areas exposed to regular rain or rinsing will reduce the concentration of corrosives.
Different grades of stainless steel contain various ratios of different elements to attain the specific qualities required by the marine industry, bearing in mind the cost factor.
Because there is no recognised industry definition for marine-grade stainless steel (AISI, ASTM, ASME, and UNS list their stainless steel products by composition, but not grades) it is of the utmost importance to ascertain whether the stainless steel components will be submerged in seawater, subjected to splashing, or exposed to salty air at or near the sea when selecting the appropriate type of marine-grade stainless steel.
For expert advice, contact Special Metal Alloys online, or give us a call at +44 [0]161 278 2386.
The following illustrations of types of common stainless steel are not intended as expert advice, but may help to select the appropriate grade for marine applications:
Contains up to 35% nickel and is used for applications such as appliances, cookware, tubing, and hardware near freshwater lakes and the sea. Offers cost-saving.
Contains about 3% molybdenum, 16% chromium and 8% nickel, increasing resistance to corrosion, acidic elements, and high temperatures. These qualities make it ideal for marine equipment, chemical, and pharmaceutical manufacturing equipment, with relatively low cost over the lifetime of components.
Contains less carbon, to improve the welding capabilities and improve corrosion resistance.
Marine-grade stainless steel with a pitting resistance number greater than 40 is typically specified as the minimum requirement if the components will be submerged in seawater or subjected to high concentrations of other grades of corrosives.
These are trade names for stainless steel grades that reportedly perform well in marine conditions. Nitronic 50 is a super austenitic marine grade steel with low magnetism and Nitronic ® 60 is a non-molybdenum grade with high levels of silicon and nitrogen to improve yield strength and performance in seawater.
Marine-grade stainless steel has been developed to achieve specific qualities resistant properties and features to withstand the challenges of marine applications, including the following:
It has excellent corrosion resistance to erosion, tea staining, pitting, intergranular corrosion, crevice corrosion, filiform corrosion, galvanic corrosion, environmental cracking, fretting corrosion, and microbial corrosion.
It has outstanding resistance to corrosion in both fresh and saltwater and alkaline and acidic environments.
It performs exceptionally well under extreme ambient and operational temperatures.
Its low carbon, but high ratios of other minerals and metals, make it highly durable. Different grades are available with impressive tensile, yield, shear, pressure, and compressive -strength.
The correct type of marine-grade stainless steel tubes can handle fluids with abrasive properties or carrying suspended solids and contaminants.
Chemical, oil, and gas industries: Pipelines, heat exchangers, chemical storage, desalination plants, offshore rigs, gas plant equipment, transporting water and sewerage.
Docks and marinas: Structural, flooring, handrails, supports, hardware, trim, and decorative applications.
Ship and boat components: Piping, tubing, hinges, propeller shafts, railings, fasteners, shackles, and hull plates in any size, from commercial freighters and passenger boats to pontoons and pleasure family boats.
Offshore platforms and processing plants: These marine environments are arguably the harshest environmental conditions possible, requiring marine-grade components at surface level, for structural supports, catwalks, handrails, and tubing.
Contact us online, or give us a quick call at +44 [0]161 278 2386 to find out more.