To understand the differences between stainless steel grades, it's important to know the characteristics of each common type. 201 stainless steel offers the best value for money, being inexpensive but prone to rusting. 304 stainless steel is the most common and widely used type, resistant to rust, high-quality, but more expensive. 316 stainless steel is an imported grade used in high-end equipment such as aerospace and food processing machinery, and comes at a premium price. Let's examine these common stainless steel grades in detail.
Differences between 304 and 201 Stainless Steel
To many consumers, 304 and 201 stainless steel may appear nearly identical. Here are some ways to distinguish between them:
Specifications: 304 is imported and higher quality, while 201 is domestically produced and of slightly lower quality but cheaper.
Composition: 201 is 17Cr-4.5Ni-6Mn-N, a nickel-saving grade. 304 is 18Cr-9Ni, the most widely used stainless steel.
Applications: 201 is used in railway vehicles, while 304 is used in food production equipment, chemical engineering, and nuclear energy.
Appearance: 201 has a bright surface with a dark sheen due to high manganese content. 304 has a matte finish.
Corrosion resistance: 201 has poorer corrosion resistance than 304 due to lower nickel content.
Hardness: 201 has higher hardness than 304 due to higher manganese content.
Chemical composition (main differences):
304: C≤0.08, Mn≤2.00, Cr 18-20, Ni 8-10
201: C≤0.15, Mn 5.5-7.5, Cr 16-18, Ni 3.5-5.5
Differences between 304 and 316 Stainless Steel
While visually indistinguishable, 304 and 316 stainless steel have several key differences:
Composition: 316 contains molybdenum, which improves corrosion resistance at high temperatures.
Grade designations: 304 corresponds to Chinese grade 0Cr18Ni9, while 316 corresponds to 0Cr17Ni12Mo2.
Performance: 316 has lower chromium but higher nickel content, plus 2-3% molybdenum, making it more corrosion-resistant than 304. It's suitable for chemical and marine environments.
Cost and applications: 316 is more expensive than 304 and is used in more demanding applications.
While visual inspection cannot differentiate between these grades, a more direct method is to use a stainless steel testing solution for identification.