Types of Stainless Steel and Their Applications

Stainless steel, the shiny silver alloy known for its corrosion resistance, scratch resistance, and long lifespan, has become a top choice across many industries. From furniture manufacturing and automotive parts to large-scale construction projects, stainless steel is trusted for both its durability and versatility.

What many people don’t realize is that stainless steel isn’t just one single material. There are different types of stainless steel, each designed for specific applications. Using the wrong type could affect efficiency, safety, and the long-term performance of a product. This guide will walk you through the five main types of stainless steel and explain which industries and applications each is best suited for.

What Is Stainless Steel Made Of?

Stainless steel is primarily an iron alloy that contains at least 11% chromium and around 10–14% nickel. These elements form a natural protective layer called a passive film, which prevents corrosion and rust. Based on their internal structure and unique properties, stainless steels are grouped into five major categories:

1. Austenitic Stainless Steel (Grades 304, 316)

Austenitic stainless steel is the most common type, widely used in multiple industries. Grades 304 and 316 are particularly popular due to their excellent corrosion resistance and ease of fabrication.

Key properties:

• Contains 18–20% chromium and 8–10.5% nickel

• Non-magnetic

• Highly resistant to corrosion and moisture

• Performs well in both high and low temperatures

• Easy to cut, weld, and form

• Long service life

Grade highlights:

• 304 Stainless Steel: Affordable, lightweight, corrosion-resistant, and ideal for general applications.

• 316 Stainless Steel: Similar to 304 but with added molybdenum (Mo), making it more resistant to salt, chemicals, and harsh environments.

Applications:

• Food and beverage industry: storage tanks, coffee machines, kitchenware

• Medical tools and lab equipment: surgical instruments, sterilizable devices

• Interior and exterior décor: handrails, door handles, wall panels

• Chemical and pharmaceutical industries: clean and sterile equipment

  
  

2. Ferritic Stainless Steel (Grade 430)

Ferritic stainless steels contain 10.5–30% chromium and low carbon, resulting in high strength and magnetic properties due to their body-centered cubic (BCC) structure.

Key properties:

• Magnetic

• Good heat resistance

• Reasonable corrosion resistance

• Easy to form and weld (though less versatile than austenitic grades)

Common grade:

• 430 Stainless Steel: Widely used in appliances and indoor applications not exposed to strong chemicals.

Applications:

• Household appliances: refrigerators, ovens, microwave panels

• Home fittings: door handles, handrails

• Automotive: exhaust systems

  
  

3. Duplex Stainless Steel (2205, 2507)

Duplex stainless steel combines the properties of austenitic and ferritic steels in roughly a 50:50 ratio. It is stronger and more corrosion-resistant than standard stainless steels, particularly against chloride stress corrosion.

Key properties:

• Twice as strong as austenitic stainless steel

• Superior resistance to chloride corrosion compared to 304 and 316

• Excellent resistance to cracking and pitting

• Partially magnetic

• Long lifespan

Common grades:

• 2205: Most widely used duplex grade, offering a balanced mix of strength and corrosion resistance.

• 2507 (Super Duplex): Advanced grade with exceptional chemical and pressure resistance.

Applications:

• Oil and gas: offshore rigs, pipelines

• Chemical industry: storage tanks and transfer pipes for corrosive chemicals

• Marine structures: ports, bridges, seawater systems

  
  

4. Martensitic Stainless Steel (Grades 410, 420, 440C)

Martensitic stainless steels are designed for exceptional hardness and strength. They can be heat-treated to improve wear resistance and toughness.

Key properties:

• 11.5–18% chromium with higher carbon content than other types

• Can be hardened through heat treatment

• Very strong and impact-resistant

• Magnetic

• Moderate corrosion resistance, not ideal for constant exposure to moisture or chemicals

Common grades:

• 410: General-purpose grade with good strength and moderate corrosion resistance

• 420: Used for surgical instruments, scissors, and knives

• 440C: Extremely hard, suitable for high-stress cutting tools and moulds

Applications:

• Cutting tools and sharp instruments: kitchen knives, surgical blades, scissors

• Mechanical parts: shafts, gears, bearings

• Engine components requiring strength and wear resistance

• Industrial moulds

  
  

5. Precipitation Hardening (PH) Stainless Steel (17-4 PH, 15-5 PH, 13-8 Mo)

PH stainless steels are engineered for high strength and corrosion resistance. They undergo special heat treatments that enhance hardness without making the material brittle.

Key properties:

• 2–3 times stronger than standard stainless steel

• Excellent corrosion resistance

• Non-magnetic

• Ideal for precision components

Common grades:

• 17-4 PH: Popular grade with excellent strength, corrosion resistance, and workability

• 15-5 PH: Offers better toughness and strength than 17-4

• 13-8 Mo: Combines high hardness and toughness, commonly used in aerospace and medical industries

Applications:

• Aerospace: aircraft components, high-load structures

• Energy: turbines, high-pressure valves, power plant equipment

• Medical: precision surgical instruments

• Electronics and moulds requiring exact dimensions

  
  

Choosing the Right Stainless Steel

Each type of stainless steel is engineered with a purpose. Selecting the right one ensures safety, durability, and cost efficiency. By matching the correct grade to your project—whether in construction, furniture, machinery, or medical tools—you not only extend the product’s lifespan but also reduce long-term maintenance costs.

If you’re unsure which stainless steel grade is right for your application, consulting with fabrication experts like Pailin Laser Metal can help you choose the perfect solution tailored to your needs.