There are many types of stainless steel.The 201 and 304 that we are familiar with are the two most widely used.Although these two types of stainless steel can be encountered in our daily lives, how to distinguish between 201 and 304 stainless steel is still the focus of most people.In this regard, Grand Metal, as a stainless steel Manufacturer with more than 15 years of production and sales experience, focuses on teaching you how to distinguish 201 VS 304 stainless steel.
201 stainless steel is an austenitic stainless steel containing chromium, nickel and manganese.It was originally developed in the 1930's as a cheaper alternative to traditional types of stainless steel.One of the distinguishing features of 201 stainless steel is its low cost compared to other grades.
Unlike some other highly corrosion-resistant stainless steels,201 stainless steel is less resistant to corrosion and rust.However, it still has good resistance to certain types of corrosion, such as atmospheric corrosion.Another advantage of 201 stainless steel is that it can be easily made into various shapes and sizes.This makes it ideal for many different applications such as cookware, automotive parts and kitchen appliances.
304 stainless steel is the modern version of "18-8"stainless steel containing approximately 18% chromium and 8% nickel and is one of the most popular types of stainless steel.It's a member of the austenitic family of stainless steels, which means that 304 stainless steel also contains nickel in addition to chromium.
304 stainless steel is a versatile, general purpose stainless steel with good resistance to atmospheric corrosion, and to many chemicals and food and beverages.These grades can be specified in the annealed condition where they have very good formability.Higher nickel versions can be specified to enhance multi-stage deep drawing characteristics.Higher strength, cold-worked conditions can also be specified for 304 stainless steel for spring type applications.304 stainless steel is non-magnetic in the annealed condition but may become slightly magnetic as a result of cold working.
Chemical Composition (wt%) limits as specified in ASTM A240 and ASME SA240*
| Element | 201 | 304 |
| Carbon | 0.15 | 0.07 |
| Chromium | 16.0-18.0 | 17.5-19.5 |
| Nickel | 3.5-5.5 | 8.0-10.5 |
| Manganese | 5.50-7.50 | 2.00 |
| Silicon | 1.00 | 0.75 |
| Nitrogen | 0.25 | 0.10 |
| Phosphorus | 0.060 | 0.045 |
| Sulfur | 0.030 | 0.030 |
Mechanical property requirements for annealed product as specified in ASTM A240 and ASME SA240
| Property | 201 | 304 |
| Yield Strength, min. (ksi) | 45 | 30 |
| Tensile Strength, min. (ksi) | 95 | 75 |
| Elongation, min. (%) | 40 | 40 |
| Hardness, max. (Rb) | 100 | 92 |
Physical properties for Type 201 and 304 stainless steel
| Property | 201 | 304 |
| Density, lb/in3 | 0.283 | 0.285 |
| Modulus of Elasticity, psi | 28.6 x 106 | 28 x 106 |
| Coefficient of Thermal Expansion, 68-212˚F, /˚F | 9.2 x 10-6 | 9.2 x 10-6 |
| Thermal Conductivity, Btu/ft hr ˚F | 9.4 | 9.4 |
| Specific Heat, Btu/lb ˚F | 0.12 | 0.12 |
| Electrical Resistivity, Microohm-in | 27.0 | 28.3 |
Spectroscopy: A portable X-ray fluorescence (XRF) analyzer can determine the exact chemical composition of the steel, revealing the different amounts of nickel, chromium, manganese, and other elements.
Chemical Spot Test: Specific chemical reagents can be used to test for the presence of nickel.304 stainless steel contains higher nickel content, so it will react differently compared to 201 stainless steel.
Both 201 and 304 stainless steels are generally non-magnetic in their annealed state. However, after cold working, 201 may exhibit slight magnetism due to its higher manganese content, whereas 304 remains non-magnetic or only slightly magnetic.
Color: 201 stainless steel may have a slightly darker color due to its lower chromium and higher manganese content.However, this difference can be subtle and not always reliable.
Surface Finish: Both types can have similar finishes, so this is not a definitive method.
Generally,201 stainless steel is cheaper than 304 due to its lower nickel content.If cost is a significant factor in the material choice, the cheaper option is likely to be 201.
Hardness and Strength: 201 stainless steel is harder and stronger due to its higher manganese content, which can be observed through mechanical testing.
Oxidation Resistance: 304 stainless steel has better oxidation resistance at higher temperatures compared to 201, which can be tested in environments exposed to heat.
To distinguish between 201 and 304 stainless steel, we must clearly understand the definition of these two types of stainless steel, the difference in chemical properties, physical properties and mechanical properties, considering their differences in composition, performance and appearance. Using a combination of the above 6 tips will provide a more reliable identification between 201 and 304 stainless steel.
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