Marine-Grade Stainless Steel 101

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Unlike standard machinery, marine equipment must endure sea air and salt spray for long periods, rusting at a faster rate for reduced operational efficiency. Stainless steel, while naturally resistant to corrosion, may still underperform in harsh marine conditions.

Marine-grade stainless steel, then, is the answer for coastal and other related applications. This variety of stainless steel boasts a particular strength, ruggedness, and high corrosion resistance compared to other metals. Read on to learn more about corrosion and the types of marine-grade stainless steel that best resist it in marine projects.

Avoiding Corrosion With Stainless Steel

In marine environments, salt is among the biggest threats to metal. It’s a highly corrosive substance, and salt spray from the sea can be a real problem for equipment in coastal operations. Through the chemical process of oxidation, iron molecules in steel produce flaky oxides on the metal’s surface when oxygen and iron molecules come into contact with water, causing deterioration. Corrosive elements like salt degrade steel components, most often in the form of rust.

One of the most common ways to avoid metal degradation is to use stainless steel, which is renowned for its anti-corrosive qualities. This alloy is mainly made up of iron, along with a combination of the following:

• Aluminum
• Chromium
• Copper
• Nickel
• Nitrogen
• Phosphorus
• Selenium
• Titanium

It’s the chromium that is primarily responsible for corrosion resistance at 10.5% or more of stainless steel’s material composition. A protective skin of chromium oxide forms on the material’s surface to safeguard the base metal against moisture exposure, preventing iron oxide and rust from forming.

Understanding the Different Grades of Stainless Steel for Marine Applications

Although all stainless steel grades are resistant to corrosion to some degree, marine-grade stainless steel is ideal for marine applications. Marine-grade steel boasts a level of corrosion and rust resistance that is superior to other metals, with various grades offering unique advantages in the marine industry.

Grade 316 Stainless Steel

Potentially the most common type of marine-grade stainless steel, Grade 316 stainless steel contains 16% chromium and up to 3% molybdenum, which is a higher percentage of this hard and tough metallic element than in other steel varieties. It also contains 8% nickel, which enhances resistance to caustic materials. This composition increases the metal’s resistance to the degradation and pitting that salt water can cause and increases marine components’ life span.

In addition to brine, Grade 316 is also highly resistant to iodides, bromides, chlorides, and sulfuric and fatty acids. It’s this durability that allows it to withstand harsh marine environments. Regarding fabrication, marine-grade stainless steel is quite compatible with welding and finishing services, making it simple to use as well as clean. Given its abilities, Grade 316 does tend to be more expensive than some other varieties, such as Grade 304.

Grade 304 Stainless Steel

Grade 304 stainless steel is another popular material that’s effective in marine environments. It’s composed of 18% chromium and 8% nickel, which give the metal good resistance qualities to caustic substances and moderate acids. It’s easy to work with, being a stainless steel grade that is simple to fabricate and clean.

This versatile metal is ideal for outdoor applications such as storage tanks, exhaust manifolds, electrical enclosures, piping, and wheel covers, and it’s available in varying aesthetics and finishes. Unfortunately, as it lacks molybdenum, Grade 304 is still prone to pitting, or localized corrosion, from chloride solutions typical in saltwater environments.

Contact AAA Metals for Marine-Grade Stainless Steel Solutions

The experts at AAA Metals Company Inc. are ready to help you choose the most suitable type of stainless steel for your marine application. Since 1978, we have built a reputation as a trusted partner for quality materials, proudly distributing numerous grades of stainless steel, titanium, nickel alloy, and hard-to-find metals. Our raw metal bars, rings, plates, forgings, discs, pipes, and tubing are available from stock, in mill form, precision cut, or polished.

We utilize our water jet and laser cutting, precision sawing, multi-shearing, and polishing capabilities to serve as your full-service supplier. Also, our global distribution network allows us to fulfill orders of virtually any size with competitive pricing to diverse businesses worldwide. To learn more about the AAA Metals difference and our material offerings for marine-grade stainless steel, contact us or request a quote today.

Food Grade Stainless Steel Selection Guide

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The food processing industry must meet strict standards and regulations for health and safety. As more and more facilities are implementing automated machinery and components for faster production, this equipment must be constructed from food-safe materials and finishes.

Food-grade stainless steel offers an optimal material choice for the food industry. Available in various grades, the many beneficial properties and features of stainless steel ensure that all food safety and hygiene standards are met, making it ideal for a wide range of food applications.

Stainless Steel Features & Benefits for the Food Industry

Stainless steel is a popular material choice for food handling applications for a multitude of reasons. Not only can the material withstand harsh temperatures, but its protective oxide layer protects against the formation of rust that could lead to food contamination. One of the most important attributes of food-grade stainless steel is that it contains no dangerous chemicals that could transfer into foods.

Other features and benefits that make stainless steel a good choice for the food industry include:

• Great corrosion resistance
• Extreme strength
• Ease of cleaning
• Non-reactive surface
• Low maintenance costs
• Impermeable surface to prevent contamination
• Available in various finishes
• Chemical and bacterial neutrality
• Made to handle frequent cleanings with harsh detergents
• Does not retain or transfer food smells

Choosing the Best Stainless Steel Food Grade for Your Application

While there are several types of stainless steel available, only a few are considered food-grade. Nearly all food-grade stainless steels come from the 300 and 400 series, including:

• 304 Grade Stainless Steel. 304 stainless steel offers an affordable option for nearly any food processing environment. It can withstand corrosion from several oxidizing acids, meaning it is easy to sanitize. It also boasts great weldability and formability, allowing it to be manufactured into various types of food processing equipment. Common applications for 304 stainless steel include storage tanks, fermentation vats, dishwashers, and more.
• 316 Grade Stainless Steel. 316 stainless steel is an austenitic alloy with high nickel and chromium content. Similar to other steel alloys, it can be continuously used at temperatures significantly higher than most food handling processes require. This grade is also resistant to chlorides (such as salt), alkalis, and acids, making it great for nearly any food application.
• 430 Grade Stainless Steel. This material has equal chromium content to grade 316 but only a fraction of the nickel content, making it a more cost-effective alternative for food processors. 430 grade stainless steel is highly resistant to organic and nitric acids, meaning it is often found in applications involving extended contact with mildly acidic compounds. This material is also resistant to oxidation, sulfur, and corrosion cracking.

Common Applications

Various applications within the food and beverage industry depend on food-grade stainless steel. Stainless steel is preferred over other materials in the following applications:

• Beer kegs
• Confectionary equipment
• Conveyor systems
• Double-wall transport containers
• Evaporator tubes
• Flour silos
• Food mixers
• Food pulverizers
• Ice cream molds
• Industrial ovens
• Peeling machines
• Syrup tanks
• Tanks holding dairy

Contact AAA Metals for Premium Stainless Steel Metal Solutions

Food-grade stainless steel is ideal for various food processing applications, offering corrosion and heat resistance, durability, neutrality, and ease of sanitization. AAA Metals has been supplying and processing stainless steel and other metals since 1978. We offer various stainless steel materials for the food industry, including food-grade stainless steel sheets, pipes, and precision-cut pieces for your desired application. In addition, we offer in-house capabilities such as finishing, polishing, shearing, precision sawing, and waterjet cutting.

For more information about stainless steel for the food industry, or to learn more about our offerings, contact us or request a quote today.