Chemical composition of grade 316 stainless steel
Grade 316 stainless steel is a type of stainless steel that belongs to the austenitic family. Its chemical composition typically includes the following elements:
- Chromium (Cr): About 16-18% by weight
- Nickel (Ni): About 10-14% by weight
- Molybdenum (Mo): About 2-3% by weight
- Iron (Fe): The remaining balance
Grade 316 stainless steel contains small amounts of carbon, silicon, manganese, phosphorus, sulfur, and nitrogen. The composition varies slightly depending on the purpose of the final product, but the above percentages are typical for 316. The addition of Molybdenum makes it suitable for marine, chemical and medical use. In our case it is mostly used in products that are used in surgical environments. The technical correct way to refer to grade 316 is 316(18/10/2). The ‘2’ refers to the Molybdenum content which 304 does not have.
Composition of grade 304 stainless steel
Grade 304 stainless steel is also known as 18-8 stainless steel, and its chemical composition typically includes the following elements:
- Chromium (Cr): About 18-20% by weight
- Nickel (Ni): About 8-10.5% by weight
- Carbon (C): About 0.08% maximum
- Manganese (Mn): About 2% maximum
- Silicon (Si): About 1% maximum
- Phosphorus (P): About 0.045% maximum
- Sulfur (S): About 0.03% maximum
- Iron (Fe): The remaining balance
The most popular austenitic stainless steel is Grade 304(18/10). It is known for its high corrosion resistance and ease of fabrication (this is crucial when fabricating bowls and intricate designs such as slop hoppers). The precise composition can vary slightly depending on the specific product or standard used, but the above percentages are typical for 304 stainless steel. It is widely used in various applications, including kitchen equipment, food processing, architectural structures, and more.
The difference between grade 304(18/10) and 304(18/8) stainless steel.
Both grade 304(18/10) and grade 304(18/8) stainless steel refer to the same material, which is stainless steel alloy 304. The numbers 18/10 and 18/8 indicate the composition of the alloy in terms of the percentage of chromium and nickel present. Specifically:
- Grade 304(18/10) stainless steel contains approximately 18% chromium and 10% nickel by weight.
- Grade 304(18/8) stainless steel contains approximately 18% chromium and 8% nickel by weight.
The main difference between the two types is the nickel content. Grade 304(18/10) has a slightly higher nickel content, and has higher resistance to corrosive chemicals or saltwater. In most applications the difference is insignificant. The environment where the steel will be used, will determine the composition required. If corrosion resistance is critical, grade 304(18/10) is better, but grade 304(18/8) may be suitable for general-purpose use. We use grade 304(18/10) because it has higher corrosion resistance to grade 304(18/8) and is also more available in sheets to our factories in South Africa.
The most common grades of Stainless Steel Sheets are, 3CR12, 430, 304L, 316L, 310, 310S, 409, 441 and 444. Grade types such as 309, 321, 321H, 347, 904L, 2205, 2304, 2507, 316Ti, 316H, 304H, LDX2101® and other are exotic grades are all available on request but we hardly fabricate products from them.