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The 4 Most Commonly Used Grades of Stainless Steel, their Composition and Properties
This detailed blog provides an easy-to-understand yet comprehensive guide to the four major types of stainless steel – 200 series, 300 series, 400 series, and duplex. Take a read to understand the differences between these series, their compositions, uses, and key characteristics.
One of the most widely used alloys on earth, stainless steel, is also one of the most versatile. From safety pins and shaving blades, coins and watches, refrigerators and washing machines, to trains, planes, and bridges, stainless steel is one of the most widely used metals used in the manufacturing of kitchenware, household appliances, automobiles, construction materials, and infrastructure.
The composition of at least 10.5% chromium gives SS a unique combination of lustre and durability. Stainless steel comes in different grades, each suited to specific applications depending on their composition and properties. JSL Global Commodities trades in (sources and distributes) a variety of stainless grades.
These include 200 series, 300 series (including SS 304, SS 316), 400 series and duplex stainless steel grades and the product range includes Stainless Steel Coils, Stainless Steel Plates, Stainless Steel Bars, Stainless Steel Sheets, Precision Strips, and Blade Steel.
The 4 Different Grades of Stainless Steel
Grade | Composition | Properties | Key Considerations | Applications |
200 Series Stainless Steel | Primarily made from nickel and manganese | Cost-effective, less corrosion-resistant compared to others | Focus on affordability but note the reduced corrosion resistance compared to the 300 series | Kitchen utensils, appliances, automotive parts |
300 Series Stainless Steel | Contains chromium and nickel | High corrosion resistance and durability | Most common type of stainless steel known for its durability and resistance to both high and low temperatures | Architectural structures, chemical equipment, and food processing equipment |
400 Series Stainless Steel | Contains chromium and a lower amount of nickel than the 300 series | Magnetic, highly resistant to wear and tear, less corrosion-resistant than 300 series | Offers better wear resistance but slightly less corrosion protection compared to the 300 series | Automotive exhaust systems, agricultural tools, kitchenware (such as knives) |
Duplex Stainless Steel | Combination of austenitic and ferritic stainless steel structures | Exceptional strength, higher resistance to stress corrosion cracking, better resistance to pitting and crevice corrosion | Known for being both strong and corrosion-resistant, making it ideal for harsh environments | Marine applications, chemical processing, oil and gas industry |
The 200 Series Stainless Steel is an austenitic alloy primarily composed of chromium (16-18%) and manganese (5-8%), with reduced nickel content (1-5%). This composition enhances its hardening ability and makes it a cost-effective option. It delivers tensile strength of around 515-690 MPa, providing good structural integrity while maintaining excellent corrosion resistance.
Excellent corrosion resistance and high strength make it ideal for general-purpose applications. Its lower nickel content makes it a cost-effective alternative to other stainless steel grades. Additionally, it provides good formability and durability in various environments, therefore, a perfect fit for kitchenware and automotive parts.
The 300 Series Stainless Steel is further available in 304 and 316 grades with slight variations – chromium (16-18%), nickel 8-10.5%, carbon up to 0.08%, manganese up to 2%, silicon up to 1%, phosphorus up to 0.045%, sulfur up to 0.03%. These specifications ensure high corrosion resistance, excellent formability, and good mechanical properties making it ideal for harsh environments.
Its high chromium and nickel content provides superior strength and durability. Additionally, it’s highly versatile, with good formability and weldability for various industrial applications, therefore a perfect fit for medical devices, food processing, and chemical processing equipment.
The 400 Series Stainless Steel primarily consists of chromium (12-18%), carbon (up to 0.15%), manganese (up to 1%), and silicon (up to 1%). This composition provides moderate corrosion resistance, making it suitable for environments with low to moderate exposure. It boasts higher hardness compared to the 300 Series, which contributes to its strength and wear resistance.
Unlike many other stainless steels, the 400 Series is magnetic, which can be advantageous for specific applications. Additionally, it can be hardened through heat treatment, enhancing its durability for demanding uses. However, it is less formable than the 300 Series, making it more appropriate for applications where complex shapes are not necessary, a perfect fit for automotive exhaust systems, and agricultural tools.
The Duplex Series Stainless Steel features a unique composition that combines austenitic and ferritic structures, providing a balance of strength and corrosion resistance. Its primary chemical composition includes 18-28% chromium, 4.5-8% nickel, 1-5% molybdenum, and 0.08-0.20% nitrogen, with iron making up the balance.
This blend results in superior tensile strength, excellent resistance to pitting, crevice, and stress corrosion cracking, as well as good ductility and toughness, even at low temperatures. While it offers moderate machinability and weldability, duplex stainless steel is highly valued in industries such as chemical processing, petrochemicals, and marine applications for its durability and performance in challenging environments.
Whether you’re considering the high corrosion resistance of the 300 Series, the strength of the 400 Series, the cost-effectiveness of the 200 Series, or the robust performance of the Duplex Series, there’s a stainless steel grade suited to every need.
Exploring the four different grades of stainless steel – each with its unique properties and applications – reveals just how versatile and essential stainless steel is across various industries. Understanding these grades helps in making informed decisions, ensuring you select the right type for your specific application.
Remember these insights to choose the best stainless steel for your needs and watch your ventures thrive with the right stainless steel grade in hand!