Stainless Steel Properties, Grades and Applications
High resistance to corrosion is just one of the many unique stainless steel properties that makes it hugely beneficial to a wide range of applications. Stainless steel is a type of steel alloy that is made primarily from iron and carbon, with at least 10.5% chromium content.
The full composition of stainless steel includes:
- Iron
- Chromium
- Nickel
- Molybdenum
- Carbon
Depending on the grade and/or application, stainless steel may also contain manganese, silicon, titanium, and nitrogen.
In this blog we will discuss stainless steel properties, grades and applications. We will also touch on the role of metal fabrication services in the process of turning sheets of stainless steel into viable products.
Stainless Steel Properties
No Corrosion: Chromium forms a thin oxide layer on the surface of the steel, which is known as the passive layer. This prevents corrosion and protects the metal from rusting.
Strong and Durable: High tensile strength and durability makes stainless steel suitable for a wide range of demanding applications, including construction and security, the science and food industries, and transportation.
Temperature Resistant: Stainless steel can withstand both very high and very low temperatures, and is fire resistant too. This makes it an ideal choice of material for work in extreme conditions – such as with the aerospace industry.
Easy to Maintain: Stainless steel is really easy to clean, sanitise and maintain. This is the main reason it is widely used in food, medical, and pharmaceutical sectors where cleanliness is crucial.
Modern and Clean Appearance: As it’s so easy to clean and preserve, you’ll maintain the shiny, modern and attractive appearance that stainless steel provides all year round.
Eco Friendly Choice: Stainless steel is 100% recyclable, making it an environmentally friendly choice of material.
Stainless Steel Grades
Stainless steel is categorised into various grades based on its chemical composition, microstructure, mechanical properties, and application. There are over 150 of them! Each grade is assigned a label/number and they all follow both national and international standards.
A lot to get your head around! Nevertheless, only around 15 of these grades are commonly used – and all 150+ can be broadly categorised into 5 main groups based on microstructure.
Austenitic Stainless Steel
This is the most common category of stainless steel, often used to create kitchen equipment and cutlery.
Common examples of austenitic stainless steel include:
- 304: Perhaps the most common stainless steel grade in the world provides excellent corrosion resistance, weldability, and formability.
- 316: Added molybdenum boosts corrosion resistance, especially in environments involving chloride.
Ferritic Stainless Steel
Ferritic stainless steels have high chromium content, making them highly resistant to corrosion, thermal fatigue and stress cracking.
Common examples of ferritic stainless steel include:
- 430: Usually less expensive than 300-series stainless steel grades. It contains less chromium in comparison but is still resistant to corrosion.
- 409: Offers great formability and weldability properties but lower corrosion resistance.
Martensitic Stainless Steel
Martensitic stainless steels provide creep resistance at higher temperatures and great strength at lower temperatures. High ductility and toughness makes them easier to form.
Common examples of martensitic stainless steel include:
- 420: High carbon content offers increased hardness and wear resistance.
- 440C: Has the highest hardness and wear resistance of all stainless steel grades.
Duplex Stainless Steel
Duplex stainless steels contain a low amount of nickel, but chromium and molybdenum content is high. This creates a material that has double the strength of typical austenitic or ferritic stainless steels.
Common examples of duplex stainless steel include:
- 2205: A combination of austenitic and ferritic stainless steel, with high strength and superior resistance to pitting and stress corrosion cracking.
- 2507: Very high resistance to chloride stress corrosion cracking and pitting.
Precipitation-Hardening Stainless Steel
Precipitation-hardening stainless steel offers high strength, good corrosion resistance, and excellent mechanical properties.
Common examples of precipitation-hardening stainless steel include:
- 17-4 PH: Can be heat-treated to achieve very high levels of strength.
- 15-5 PH: Similar to 17-4 PH but with improved toughness and ductility.
Stainless Steel Applications
Stainless steel’s combination of properties, longevity, and reliability makes it an essential material across various applications.
Common uses and applications include:
- Construction and Architecture: Stainless steel is used to create various structural components such as cladding, handrails, decorative elements, kiosks, vending machines and enclosures. This is due to stainless steel properties such as strength, durability, and aesthetic appeal.
- Automotive and Aerospace: Exhaust systems, aircraft frames, and transportation components make use of high-strength and corrosion-resistant stainless steel.
- Food and Beverage Industry: Stainless steel is commonly used in kitchen equipment, food processing machinery, and storage tanks because of its hygienic and corrosion resistant properties.
- Medical and Pharmaceutical: For the same reasons, stainless steel is also used in surgical instruments, implants, and pharmaceutical equipment.
- Chemical Processing: Duplex stainless steels are often used in chemical processing plants to handle or transport corrosive chemicals.
- Marine Applications: Boat fittings, fasteners, and other components exposed to saltwater or chloride can benefit from stainless steel.
The Role of Metal Fabrication Services
Metal fabrication services allow you to turn flat sheets of stainless steel into metal structures or products. This usually involves combining separate metal components to form a larger end product.
The sheet metal fabrication process can include a number of different techniques and procedures, such as:
- Bending – sometimes known as CNC folding or CNC press braking.
- Welding – including spot welding, MIG and TIG welding, and robot welding.
- Laser cutting –used to cut to absolute precision.
- Punching – accurately add perforations or forms to sheet metal pieces
- CAD design – we use SOLIDWORKS, an industry leading software package.
- Powder coating and finishing – protects the metal from scratches, marks, scuffs and corrosion.
Expert Metal Fabrication Services from Salamander
Here at Salamander Fabrications we understand design and manufacturing and specialise in sheet metal fabrication. With over 50 years’ experience building and creating products for a wide range of applications, we have the know-how to turn your product requirements into reality.
Feel free to contact us, give us a call on 01484 843599 or send an email to sales@salamanderfabs.com if you have any questions or would like some more information. Our friendly sales team will be more than happy to help!
