Why is stainless steel the preferred metal for corrosion-resistant applications?

Stainless steel: The preferred metal for corrosion resistance applications

The characteristics of stainless steel: Stainless steel is widely used in industry and the environment due to its corrosion resistance, strength and durability. It contains at least 10.5% chromium, which enables stainless steel to naturally resist rust and stains when exposed to moisture and chemicals.

The corrosion resistance of stainless steel: The chromium content in stainless steel forms a thin and invisible oxide layer on the surface. This protective film prevents oxygen and moisture from penetrating and reaching the iron content in the steel, effectively stopping the occurrence of the corrosion process.

Types of stainless steel and their corrosion resistance:

1.Austenitic stainless steel: The most common type, renowned for its excellent corrosion resistance, formability and non-magnetism. For instance, grades 304 and 316, among which 316 also contains molybdenum, further enhancing its corrosion resistance.

2. Ferritic stainless steel: such as grade 430, it contains chromium (10.5%-30%) but usually has a low carbon content, is magnetic, and has good resistance to stress corrosion cracks.

3. Duplex stainless steel: It combines the properties of austenitic and ferritic, offering higher strength and corrosion resistance. For example, grade 2205 has a very high resistance to local corrosion such as pitting corrosion and crevice corrosion.

4. Martensitic stainless steel: It is renowned for its high carbon content and ability to harden through heat treatment. For instance, grades 410 and 420 are used in applications that require high strength and moderate corrosion resistance.

The application of stainless steel in key industries:

1. Medical and pharmaceutical industries: Stainless steel, especially grade 316, is widely used due to its ease of disinfection, resistance to body fluid erosion, and resistance to strong cleaning agents.

2. Food and beverage processing: Stainless steel is the preferred material for food processing equipment, storage tanks and kitchen appliances because it does not give food an odor, is resistant to the corrosion of food acids and is easy to clean.

3. Marine applications: In Marine environments, 316 stainless steel and others offer better corrosion resistance due to their increased molybdenum content, making them ideal materials for Marine fittings, underwater pipes, and coastal building structures.

4. Chemical and petrochemical processing: Stainless steel, especially duplex and certain austenitic grades, can withstand acidic and alkaline conditions without degradation.

5. Architecture and Construction: Stainless steel, due to its resistance to rust and stains, is an ideal choice for structures exposed to elements.

Advantages of stainless steel in corrosive environments:

• Low maintenance: The high durability and corrosion resistance of stainless steel make it require less maintenance than other metals.

• Longevity and cost-effectiveness: Although stainless steel has a relatively high initial cost, its long service life makes it a cost-effective choice in the long term.

• Hygiene features: The smooth surface of stainless steel is impermeable, meaning it will not breed bacteria or mold.

• Recyclability and sustainability: Stainless steel is fully recyclable, with approximately 60% of stainless steel products made from recycled materials.

Select the appropriate stainless steel grade: The choice of the correct stainless steel grade depends on the specific requirements of the environment and application. The factors to be considered include corrosive environments, temperature resistance, strength requirements and budget.