​What is the Difference Between Stainless Steel 304 and 201?

What is the Difference Between Stainless Steel 304 and 201?

In the eyes of many consumers, Stainless Steel 304 and 201 appear almost indistinguishable, making it difficult to tell them apart with the naked eye. Here are some methods to differentiate between 304 and 201 stainless steel materials.

Specifications: Common stainless steel sheets are divided into two grades: 201 and 304. The actual difference lies in their composition. Grade 304 offers better quality but is more expensive, while 201 is of lower grade. Typically, 304 is an imported stainless steel plate, whereas 201 is a domestic stainless steel plate.

201 Composition: Designated as 17Cr-4.5Ni-6Mn-N, it is a nickel-saving steel type and a substitute for 301 steel. It becomes magnetic after cold working and is used for railway vehicles.

304 Composition: Designated as 18Cr-9Ni, it is the most widely used stainless and heat-resistant steel. It is applied in food production equipment, general chemical equipment, nuclear energy, etc.

Appearance and Corrosion Resistance: Grade 201 contains higher manganese, giving it a bright surface with a darkish sheen, and it is more prone to rusting. Grade 304 contains more chromium, presenting a matte surface and is rust-resistant. When placed side by side, the difference is noticeable. The most crucial distinction is in corrosion resistance: 201 has poor corrosion resistance, making it significantly cheaper. Due to its lower nickel content, 201 is less expensive than 304, but consequently, its corrosion resistance is inferior.

Key Difference: The primary difference between 201 and 304 stainless steel materials lies in their nickel content. Currently, 304 is more expensive, but it guarantees rust-free performance during use (this can be tested using stainless steel testing solution).

Rust Resistance Principle: Stainless steel resists rusting due to the formation of a chromium-rich oxide layer on the surface that protects the steel body. Grade 201, being a high-manganese stainless steel material, is harder than 304 but has high carbon and low nickel content.

Composition Differences (Differentiating 201 and 304 primarily based on Carbon, Manganese, Nickel, and Chromium content):

Steel Grade Carbon (C) Silicon (Si) Manganese (Mn) Phosphorus (P) Sulfur (S) Chromium (Cr) Nickel (Ni) Molybdenum (Mo) Copper (Cu)

AISI (304) ≤0.08 ≤1.00 ≤2.00 ≤0.045 ≤0.03 18-20 8-10 - -

AISI (201) ≤0.15 ≤1.00 5.5-7.5 ≤0.05 ≤0.03 16-18 3.5-5.5 -