PROGRESSO
AISI 904L stainless steel (UNS N08904) is a high alloy austenitic stainless steel. Compared with 316L, SS904L has lower carbon (C) content, higher chromium (Cr) content, and approximatively twice the nickel (In) and molybdenum (Mo) content of 316L, which makes it have higher high temperature oxidation resistance, pitting resistance, and resistance to reducing acid (eg, sulfuric acid). Nitrogen (N) can reduce the rate of chromium carbide precipitation, thereby reducing the sensitivity of sensitization, it also improve the resistance to pitting and crevice corrosion caused by chlorides. Especially its addition of copper (Cu) makes it useful for all concentrations of sulfuric acid.
Datasheet and Specification
The following data sheet summarizes the chemical composition, properties, heat treatment and equivalent grade of 904L stainless steel (SS904L).
Composizione chimica
The following data sheet gives SS 904L stainless steel chemical composition.
| Composizione chimica, % | |||||||||||||
| ASTM | UNS | Type | C, ≤ | E, ≤ | Mn, ≤ | P, ≤ | S, ≤ | Cr | In | Mo | N, ≤ | Cu | Notes (Product) |
| ASTM A276/A276M | UNS S08904 | 904l | 0.02 | 1.00 | 2.00 | 0.045 | 0.030 | 19.0-23.0 | 23.0-28.0 | 4.0-5.0 | 0.10 | 1.0-2.0 | Bars and Shapes |
| ASTM A240/A240M | Plate, Sheet, and Strip | ||||||||||||
Proprietà meccaniche
The following table lists Rolex 904L stainless steel (SS904L) mechanical properties such as yield strength, resistenza alla trazione, elongation and hardness.
| AISI ASTM 904L Steel Mechanical Properties | |||||||
| ASTM | AISI Type | Resistenza alla trazione, MPa (ksi), ≥ | 0.2% Forza di snervamento, MPa (ksi), ≥ | Elongation in 50 mm (2 in.), %, ≥ | Rockwell Hardness (HRBW), ≤ | Product forms | Conditions |
| ASTM A276/A276M | 904l (UNS N08904) | 490 (71) | 220 (31) | 35 | – | Bars and Shapes | Annealed, Hot-finished or cold-finished |
| ASTM A240/A240M | 490 (71) | 220 (31) | 35 | 90 | Plate, Sheet, and Strip | ||
Heat Treatment
Ricottura: The recommended annealing temperatures for 904L wrought steel is 1095 °C (2000 °F).
Corrosion
Type 304 stainless steel can handle mild foods and vegetables, but sauces and pickle liquors are more corrosive and can even cause pitting corrosion on type 316 stainless steel. In order to improve pitting resistance, high alloy 904L stainless steel (SS904L) should be considered.
Applicazioni
904L stainless steel (SS904L) is used in petroleum, chemical, fertilizer, marine development towers, tanks, pipes and tubes and heat exchangers. Rolex and other watch manufacturers also use it to make watches.
