What Is The Difference Between 302 And 304 Stainless Steel
Austenitic stainless steels with non-magnetic characteristics make up both of the materials. Both of them contain chromium and nickel, which gives them corrosion resistance and strength capabilities. The composition of the 302 material includes a minimum of 17% chromium, 8% nickel, and 0.15 percent carbon. The 304 material has a 0.8% carbon content, a minimum chromium content of 19%, and a minimum nickel content of 8%. The 304 material is slightly more corrosion resistant than the 302 material because it contains more chromium.
However, the strength values of the 302 material are greater than those of the 304 material. The minimum tensile strength of material 302 is 585MPa, while that of material 304 is 515MPa. Additionally, whereas the yield strength of 304 is only 205MPa, that of 302 is 240MPa. In addition, the elongation at break for 302 is greater than for 304. The 302 material is harder than 304 because it contains more carbon than 304. The 304 material is more ductile whereas the 302 material is tougher and stronger.
Both of these materials are comparable in price, although the 304 material is slightly more expensive than the 302. Despite being less expensive, the 302 material is more challenging to manufacture and mould than the 304. In applications where the 302 is only utilised when the 304 is not essential and when heavy welding or machining processes are not needed, the 304 material is therefore most frequently used.
When compared to the 304 material, the 302 has more carbon. Both of these materials can be welded without the requirement for preheating or post-weld heat treating, however there is a chance that chromium carbide will precipitate during the welding process. In comparison to the 302 material, the 304 material has a lower carbon content, is simpler to weld, and exhibits less intergranular corrosion and precipitation of chromium carbide. The 302 material is substantially more susceptible to intergranular corrosion and loses strength at welded seams because more chromium carbide precipitation forms during the welding procedures.
The 304 material has a high melting point of 1450 degrees Celsius thanks to its higher nickel concentration and lower carbon content. The lower melting point of 302 substance is 1421 degrees Celsius. The operational temperature range is impacted by the melting point variation. The 304 material should logically be able to withstand higher temperatures than the 302 material. The 302 material performs well at lower temperatures whereas the 304 material can withstand operating temperatures up to 870 degrees Celsius.
The 302 material works well in applications requiring high strength, minimal corrosion, and low temperatures. The 304 material is preferred when operating under corrosive conditions that the 302 material cannot withstand and at greater operating temperatures. Both of these materials have uses in the building, oil and gas, and general corrosive industries.
8 - 10 | Ni |
17-19 | Cr |
2 | Mn |
0.045 | P |
0.15 | C |
1.00 | Si |
0.03 | S |
Grade | Elongation (% in 50mm) minimum | Strength of Yield 0.2% Proof (MPa) minimum | Strength of Tensile (MPa) minimum | Pipe Hardness | ||
Rockwell B (HR B) maximum | Brinell (HB) maximum | |||||
304 | 40 | 205 | 515 | 92 | 201 |
Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
304 | min. | – | – | – | – | – | 18.0 | – | 8.0 | – |
max. | 0.08 | 2.0 | 0.75 | 0.045 | 0.030 | 20.0 | 10.5 | 0.10 |
Type | Old British | Euronorm | Swedish SS | UNS | JIS | ||
En | BS | Name | No | ||||
304 | 58E | 304S31 | X5CrNi18-10 | 1.4301 | 2332 | S30400 | SUS 304 |