When it comes to marine environments, there’s no room for compromise. The relentless salt water, humidity, and constant exposure to harsh elements demand a material that can withstand the test of time. That’s where stainless steel grade 316 shines bright like a beacon in the sea mist.

Renowned for its exceptional corrosion resistance and durability, this remarkable alloy has become the go-to choice for marine applications worldwide. Today, we will dive deep into why stainless steel grade 316 is ideal for marine environments.

At TOPSON, we offer a wide range of surface finishes for 316 stainless steel sheets, which can be selected in different thicknesses (0.5 mm, 1mm, 2mm, etc.) and custom-sized:

Mirror polishing
Bead blasting
Circular polishing
PVD coating
Embossed
Etched
Patina

Table of Contents

Stainless Steel Grade 316

Stainless steel grade 316 is a popular and highly versatile material renowned for its corrosion resistance and durability. It is often called marine-grade stainless steel due to its excellent performance in harsh seawater environments. This section will delve deeper into the properties and characteristics of stainless steel grade 316 and understand why it is the ideal choice for marine applications.

Composition
Stainless steel grade 316 comprises iron, chromium, nickel, molybdenum, and small amounts of manganese, silicon, phosphorus, sulfur, and carbon. Adding molybdenum (2-3%) makes this grade more corrosion-resistant than other types of stainless steel. The high nickel content (10-14%) also contributes significantly to its corrosion resistance.

Corrosion Resistance
AISI 316 stainless steel is more resistant to pitting and crevice corrosion than other grades due to Mo. This makes it suitable for use in saltwater or brackish water environments with high levels of chloride ions that can cause rusting.

Durability
Grade 316 has a higher tensile strength than most other types of stainless steel grades, making it less prone to bending or breaking under pressure or stress. This makes it suitable for use in harsh and demanding marine environments.

Heat Resistance
Stainless steel grade 316 can maintain strength and corrosion resistance at temperatures up to 1700°F (925°C), making it suitable for high-temperature applications such as engine parts or boat exhaust systems.

Machinability
While stainless steel grade 316 is more difficult to machine than other grades, it can still be machined with proper techniques and tools. It is recommended to use slower speeds, heavier feeds, and more rigid equipment when machining this grade of stainless steel.

Weldability
Stainless steel grade 316 has excellent weldability, making fabricating it into various shapes and structures easy. However, it is essential to use the correct welding procedures and filler materials to prevent any loss of corrosion resistance in the welded area.

Due to its extraordinary properties, stainless steel grade 316 is widely used in various industries and has proven reliable and cost-effective for many applications.

Properties and Characteristics of 316 Stainless Steel

In contrast to other stainless steel grades, AISI 316 stainless steel plates possess the following benefits:

1. Excellent corrosion resistance
2. High strength and durability
3. Extraordinary Heat Resistance
4. Non-magnetic
5. Formability and weldability
6. Low Carbon Content
7. Easy Maintenance
8. Aesthetic Appeal
9. Biocompatibility
10. Higher expansion rate
11. Higher stability (for example, when used in an environment with salty or acidic air.)

AISI 316 stainless steel has excellent mechanical and anti-corrosive properties even at extreme temperatures. It is easy to process and weld and has increased ductility and better formability.

316 stainless steel properties | TOPSON

Is AISI 316 / AISI 316L stainless steel magnetic

AISI 316 stainless steel sheets, like 316L or 304 plates, are non-magnetic or very weakly magnetic.

The magnetic or non-magnetic properties of stainless steel depend on the nickel content in its composition. The stainless steel begins to magnetize only when the nickel content is reduced to 9 % or less, even if it is Austenitic stainless steel.

TOPSON’s grade AISI 316 / AISI 316L usually contains between 10 and 13 wt% of nickel, making this steel non-magnetic.

Can’t tell if your stainless steel products are magnetic? Please browse on our blog about “Is stainless steel magnetic.

Why is Stainless Steel Grade 316 Ideal for Marine Environments

Stainless steel grade 316, also known as marine-grade stainless steel, is the most commonly used material in marine environments. This is due to its exceptional corrosion resistance and durability, making it an ideal choice for various applications in the marine industry.

One of the main reasons why stainless steel grade 316 is ideal for marine environments is its high corrosion resistance. Seawater’s harsh and corrosive nature can quickly deteriorate other types of metals, but stainless steel grade 316 has a unique composition that makes it highly corrosion-resistant. This is because it contains higher levels of chromium (16-18%) and Nickel (10-14%) than other grades of stainless steel.

Chromium acts as a protective layer on the surface of the metal, preventing oxygen and moisture from reaching the underlying material. It also reacts with oxygen to form a thin yet robust oxide film that protects against pitting and crevice corrosion. On the other hand, Nickel helps stabilize this oxide layer, making it even more effective at protecting against corrosion.

Stainless steel grade 316 contains Mo (2-3%), which enhances its resistance to chloride-containing environments such as seawater. Chloride ions are notorious for causing pitting and stress-corrosion cracking in metals. Still, with molybdenum’s presence in stainless steel grade 316, these harmful ions cannot penetrate the protective oxide layer.

Another crucial factor that makes stainless steel grade 316 ideal for marine environments is its strength and durability. It has a high tensile strength, meaning it can withstand heavy loads and extreme forces without breaking or bending. This makes it suitable for use in structures such as ship hulls, cargo containers, and offshore oil rigs.

Furthermore, stainless steel grade 316 can withstand temperatures up to 1500 degrees Fahrenheit (815 degrees Celsius) without losing its mechanical properties, making it suitable for applications that require exposure to high temperatures. 316 stainless steel is highly resistant to thermal expansion and contraction. This means it can withstand significant changes in temperature without warping, cracking, or becoming brittle.

In addition to its corrosion resistance and durability, stainless steel grade 316 has aesthetic appeal. Its smooth and shiny surface makes it an attractive choice for various decorative elements on ships and boats.

Overall, the exceptional heat resistance of stainless steel makes it a reliable and durable material for use in marine environments. It can withstand high temperatures, resist corrosion, maintain strength and stability, and remain structurally sound even under extreme conditions.

316 stainless steel physical properties | TOPSON

Common Applications of Stainless Steel Grade 316 in Marine Environments

Stainless steel grade 316 is a versatile and highly corrosion-resistant material commonly used in marine environments. Its unique properties make it ideal for various applications, from small recreational boats to large commercial vessels. This section will discuss some of the most common applications of stainless steel grade 316 in marine environments.

1. Boat Building and Construction
2. Marine Equipment
3. Offshore Oil and Gas industries
4. Marine Exhaust Systems
5. Underwater Components
6. Seawater Desalination Equipment
7. Dock Hardware
8. Construction of specialized industrial plants in chemical, food, paper, and cellulose production.
9. Architecture or construction: facades, roofs, and cladding.
10. Mining, pharmaceutical, and petrochemical industries: constructing containers, silos, vessels, tanks, pipes, etc.

In conclusion, stainless steel grade 316 is a versatile material that has become essential to many special applications due to its exceptional strength, durability, and corrosion resistance properties.

Designations for AISI 316 Stainless Steel

The designations for AISI 316 stainless steel can vary depending on the standard or specification. Here are some commonly used designations for AISI 316:

AISI 316: The AISI (American Iron and Steel Institute) designation is widely recognized and used in North America.

UNS S31603: The Unified Numbering System (UNS) designation is an internationally recognized system for identifying metals and alloys. The “S31603” specifically refers to AISI 316 stainless steel.

EN 1.4404: This is the European norm designation according to EN 10088, which covers stainless steel. The “1.4404” is the specific grade number for AISI 316.

ASTM A240/A240M: ASTM A240/A240M includes AISI 316 as one of the covered grades.

ASME SA240/SA240M: ASME SA240/SA240M includes AISI 316 as one of the covered grades.

The Standard of 316 Stainless Steel

Various international organizations and bodies define the standard for 316 stainless steel. The most widely recognized and used standards for AISI 316 stainless steel are:

ASTM International: ASTM A240/A240M – Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and General Applications.

American Society of Mechanical Engineers (ASME): ASME SA240/SA240M – Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and General Applications.

European Standards (EN): EN 10088 – Stainless steels – Part 1: List of stainless steels and EN 10088-2 – Stainless steels – Part 2: Technical delivery conditions for sheet/plate and strip of corrosion-resistant steels for general purposes.

International Organization for Standardization (ISO): ISO 15510 – Stainless steels – Chemical composition.

These standards define the chemical composition, mechanical properties, and other AISI 316 stainless steel requirements, ensuring consistency and quality across different manufacturers and applications. They provide guidance and specifications for producing, testing and using 316 stainless steel in various industries and applications.

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