Common stainless steel plate numbers and chemical compositions
Stainless steel is an alloy of iron, chromium, and occasionally other elements such as nickel, molybdenum, or nitrogen. These elements combine together to create a corrosion-resistant material, which is harder and stronger than carbon steel. While stainless steel can be used to create everything from cookware and cutlery to aircraft parts and medical instruments, there are various grades and specifications that can vary in chemistry, mechanical properties, and surface finish. Here, we take a look at the most common stainless steel plate numbers and chemical compositions.
Grade 304 (UNS S30400)
Grade 304 stainless steel is the most common austenitic stainless steel. It is also referred to as 18/8 stainless steel because of its composition, which includes 18% chromium and 8% nickel. Grade 304 is incredibly versatile and is most commonly used to produce kitchen ware, as well as electrical materials, building materials, and automotive parts. It exhibits superior corrosion resistance, making it suitable for chemical and food processing applications.
Grade 304 is composed of:
• 18-20% chromium
8-10.5% nickel
• 0.08% carbon
• 2% manganese
• 0.75% silicon
• 0.045% phosphorous
• 0.03% sulfur
• 0-1.0% nitrogen
• Bal: Iron
Grade 316 (UNS S31600)
Grade 316 is the next most common austenitic stainless steel. It is similar to grade 304 but with a higher level of molybdenum added to increase corrosion resistance. It is commonly used in food processing and marine applications.
Grade 316 is composed of:
• 16-18% chromium
• 10-14% nickel
• 0.08% carbon
• 2% molybdenum
• 2% manganese
• 0.75% silicon
• 0.045% phosphorous
• 0.03% sulfur
• 0-1.0% nitrogen
• Bal: Iron
Grade 304L (UNS S30403)
Grade 304L is an extra-low-carbon variant of grade 304 stainless steel. It is most commonly used for deep drawing and spinning applications, due to its increased ductility. Grade 304L exhibits superior corrosion resistance compared to other austenitic stainless steels, making it suitable for food processing and architectural applications.
Grade 304L is composed of:
• 18-20% chromium
• 8-12% nickel
• 0.03% carbon
• 2% manganese
• 0.75% silicon
• 0.045% phosphorous
• 0.03% sulfur
• 0-1.0% nitrogen
• Bal: Iron
Grade 316L (UNS S31603)
Grade 316L stainless steel is an extra-low-carbon variant of grade 316. It is most commonly used for deep drawing and spinning applications, due to its increased ductility. It exhibits superior corrosion resistance compared to other austenitic stainless steels, making it suitable for food processing and architectural applications.
Grade 316L is composed of:
• 16-18% chromium
• 10-14% nickel
• 0.03% carbon
• 2% molybdenum
• 2% manganese
• 0.75% silicon
• 0.045% phosphorous
• 0.03% sulfur
• 0-1.0% nitrogen
• Bal: Iron
Grade 347 (UNS S34700)
Grade 347 stainless steel is an austenitic stainless steel alloy with higher levels of chromium and tantalum than grade 304. It provides enhanced corrosion resistance and is often used in applications that require welding or forming. It is particularly suitable for chemical and petrochemical processing, as well as medical and food processing.
Grade 347 is composed of:
• 17-19% chromium
• 9-13% nickel
• 0.08% carbon
• 2% niobium
• 2% manganese
• 0.75% silicon
• 0.045% phosphorous
• 0.03% sulfur
• 0-1.0% nitrogen
• Bal: Iron
Grade 410 (UNS S41000)
Grade 410 stainless steel is a martensitic stainless steel that contains 11.5-13.5% chromium, making it suitable for mild corrosion resistance, particularly in fasteners and hardware. It also offers excellent hardening properties and can be used in applications that require high strength and hardness.
Grade 410 is composed of:
• 11.5-13.5% chromium
• 0.15% carbon
• 1% manganese
• 1% silicon
• 0.04% phosphorous
• 0.03% sulfur
• Bal: Iron
Grade 430 (UNS S43000)
Grade 430 stainless steel is a ferritic stainless steel that contains between 0.12-0.17% carbon, making it suitable for corrosion resistance. It is resistant to acids, chemicals, and salt water, making it ideal for architectural and medical applications. It also offers excellent formability and elongation, making it ideal for harsh environments.
Grade 430 is composed of:
• 16-18% chromium
• 0.12-0.17% carbon
• 0.75% silicon
• 0.045% phosphorous
• 0.03% sulfur
• Bal: Iron
