What Is The Difference Between 302 And 304 Stainless Steel
Both the materials are austenitic stainless steels with non-magnetic properties. They both have chromium and nickel in the composition which makes them to have corrosion resistance and strength properties. The 302 material has 0.15% carbon, 17% minimum chromium and 8% minimum nickel in the composition. The 304 material has 0.08% carbon, 19% minimum chromium and 8% minimum nickel in the composition. The chromium content in the 304 material makes it a little bit more corrosion resistant than the 302 material.
The 302 material however, has higher strength values than the 304 material. The minimum tensile strength of 304 is 515MPa and the minimum tensile strength of the 302 material is 585MPa. Also the yield strength of 302 is 240MPa while that of the 304 is only 205MPa. The elongation at break for 302 is higher than that of the 304 as well. The 302 material has higher carbon content compared to the 304 which makes it tougher than 304. While the 302 is more tough and stronger, the 304 material is more ductile.
Price Difference Between 302 And 304
The prices of both these materials are similar but the 304 material is slightly costlier than the 302. Even with the low cost, the 302 is difficult to machine and form compared to the 304 material. Therefore the 304 material is the most used in applications where the 302 is used only where the 304 is not necessary and where heavy welding or machining operations are not needed.
302 And 304 Stainless Steel Welding
The 302 has higher carbon compared to the 304 material. Welding of both these materials does not need preheating or post weld heat treatment, but these materials have the chromium carbide precipitation possibility at welding. With low carbon content, the 304 material is easy to weld with and causes lower chromium carbide precipitation and intergranular corrosion compared to the 302 material. The formation of more chromium carbide precipitation during the welding procedures of the 302 material makes it much prone to intergranular corrosion and decreased strength at welded joints.
302 And 304 Stainless Steel Melting Point
With lower carbon content and high nickel content, the 304 material has a high melting point of 1450 degrees Celsius. The 302 material has lower melting point of 1421 degrees Celsius. The difference in the melting point affects the operating temperature range. Logically, the 304 material can operate at higher temperatures than the 302 material. The operating temperatures for the 304 material can range up to 870 degrees Celsius whereas the 302 material performs better at lower temperatures.
The applications that involve high strength, low corrosion and low temperatures can use the 302 material without a problem. Where there are corrosive conditions that the 302 material cannot handle and the required operating temperatures are higher, the 304 material is preferred. The applications of both these materials include oil and gas, general corrosive and construction applications.