What Is The Difference Between 204 And 304 Stainless Steel
The nickel content varies in these different grades. The composition is the main difference and it causes differences in the mechanical, physical and chemical properties of the materials. The 204 steels can have up to 18% chromium and 0.5% nickel where the 304 can have up to 20% chromium and 10% nickel. The nickel content is almost 20 times higher in the 304 material grade. The silicon, phosphorus, sulfur and molybdenum contents vary according to specifications as well. As a result of these difference in the composition, the corrosion resistance properties differ and the applications are different as well. One other major compositional difference is the manganese content. 304 steels have up to 2% manganese where the 204 can have up to 5% manganese.
How To Identify Stainless Steel 204 And 304
Both the materials are austenitic stainless steels and have non-magnetic properties. They both look similar as well. When allowed to react with corrosive agents, the 204 grade corrodes faster. Application of salt water can show the rust or stain building faster in the 204 grade than in the 304 grade. Another simple test could be to have a spark test. The 204 material produces yellowish red sparks due to the lower nickel content when ground with a grinder. The 304 sparks are more reddish. Also the 304 sparks travel faster where the 204 sparks travel less distance. There are magnetic spot tests and other laboratory tests which can accurately identify the material. Also, the markings on the products could be useful in knowing the material grade.
Grade 204 Vs 304 Corrosion Resistance
Since the 204 has lower nickel, it is definitely less corrosion resistant than the 304 grade. The 304 grade has good corrosion resistance and toughness. It could be used for kitchenware and other home based utensils as well as industrial applications such as oil and gas, petroleum, petrochemical, water lines, construction and automobile industries. The 204 is however a cheaper replacement where the corrosion resistance is not the greatest concern. The 204 material also gets better ductility and low toughness due to the lack of nickel and the addition of manganese in the composition.
Difference In SS 204 And 304 Material Price Per Kg
Nickel is an expensive material. Since about 10% of the 304 is made up of nickel and the 204 only has twenty times less nickel, the 204 is the cheaper one. If the cost efficiency is the main concern and not the corrosion resistance, such as in kitchen appliances or everyday utilities, the 204 is the most preferred. If a daily maintenance is applied, then the stain building would be managed. On the other hand, the 304 material is used where the strength, corrosion resistance and toughness are needed. But it is expensive than the 204 grade.
204 And 304 Stainless Steel Weldability
Both materials can be welded with traditional welding methods. The 304 material is the easiest to weld apart from the toughness. 204 is also easier to weld but has less welding ease compared to the 304 grade. Both applications are used in different circumstances and the 304 is preferred for applications with high welding procedures.
Chemical Material Composition Of 304 Stainless Steel
Yield Strength Of Grade 304
Elongation (% in 50mm) minimum
Strength of Yield 0.2% Proof (MPa) minimum
Strength of Tensile (MPa) minimum
Rockwell B (HR B) maximum
Brinell (HB) maximum
Equivalent Material Of Stainless Steel 304
chemical properties of 204 stainless steel
Weldability of SS 204
Reasonable, if thickness exceeds 6mm then sensitive to intergranular corrosion
Post-weld passivation and cleaning is critical.
Mechanical Database of SS 204
310 Min MPa
655 Min MPa
Elongation A50 mm
40 min %
204 stainless steel Density
UNS S20400 Physical Property
17 x10^-6 /K
Modulus of Elasticity
Heat Resistance of SS 204
Oxidation resistance is almost same to 1.4310 (301) Grade up to 840°C.