| Customization: | Available |
|---|---|
| Type: | Sheet |
| Standard: | AISI, ASTM, DIN, JIS, GB |
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309 stainless is an austenitic heat-resistant alloy with oxidation resistance to 1900°F under constant temperature conditions. When frequent thermal cycling is involved, the alloy is resistant to about 1850°F. The high chromium and relatively low nickel content of 309 provide good resistance to high temperature sulfur bearing atmospheres. 309 has only moderate resistance to carbon absorption and is not suggested for use in highly carburizing atmospheres.
Often in many product forms, the grain size and carbon content can meet both the 309S and 309H requirements. Prolonged exposure to the 1100-1600°F temperature range will cause some sigma to form, lowering room temperature ductility and impact resistance. Should sigma formation be anticipated, care should be taken to avoid heavy mechanical impact at room temperature.
309 has a machinability rating of 43% relative to AISI B1112 steel. Room temperature forming is suggested. Weld with AWS E309-16 covered electrodes or ER309 bare wire.
The following table shows the chemical composition of grade 309 stainless steel.
| Element | Content (%) |
| Iron, Fe | 60 |
| Chromium, Cr | 23 |
| Nickel, Ni | 14 |
| Manganese, Mn | 2 |
| Silicon, Si | 1 |
| Carbon, C | 0.20 |
| Phosphorous, P | 0.045 |
| Sulfur, S | 0.030 |
| Grade | UNS | DIN | EN | AMS | ASTM | JIS | |
| 309 |
S30900 |
- | 1.4833 | AMS 5523 | ASTM A240 ASTM A276 ASTM A312 ASTM A479 |
- | |
The physical properties of grade 309 stainless steel are given in the following table.
| Properties | Metric | Imperial |
| Density | 8 g/cm3 | 0.289 lb/in³ |
| Melting point | 1455°C | 2650°F |
The following table outlines the mechanical properties of annealed grade 309 stainless steel.
| Properties | Metric | Imperial |
| Tensile strength | 620 MPa | 89900 psi |
| Yield strength (@ strain 0.200%) | 310 MPa | 45000 psi |
| Izod impact | 120 - 165 J | 88.5 - 122 ft-lb |
| Shear modulus (typical for steel) | 77 GPa | 11200 ksi |
| Elastic modulus | 200 GPa | 29008 ksi |
| Poisson's ratio | 0.27-0.30 | 0.27-0.30 |
| Elongation at break (in 50 mm) | 45% | 45% |
| Hardness, Brinell | 147 | 147 |
| Hardness, Rockwell B | 85 | 85 |
| Hardness, Vickers (converted from Rockwell B hardness) | 169 | 169 |
The thermal properties of grade 309 stainless steel are displayed in the following table.
| Properties | Metric | Imperial |
| Thermal expansion co-efficient (@ 0-100°C/32-212°F) | 14.9 µm/m°C | 8.28 µin/in°F |
| Thermal conductivity (@ 0-100°C/32-212°F) | 15.6 W/mK | 108 BTU in/hr.ft².°F |
Technology
Machinability
Grade 309 stainless steel can be machined similar to that of 304 stainless steel.
Welding
Grade 309 stainless steel can be welded using fusion or resistance welding methods. Oxyacetylene welding method is not preferred for welding this alloy.
Hot Working
Grade 309 stainless steel is hot worked at 1177°C (2150°F) followed by reheating at 982°C (1800°F). It can be then quenched rapidly. Post-work annealing can be done to restore its corrosion resistance property.
Cold Working
Grade 309 stainless steel can be headed, upset, drawn, and stamped even though it has high work hardening rate. Annealing is performed after cold working in order to reduce internal stress.
Annealing
Grade 309 stainless steel is annealed at 1038-1121°C (1900-2050°F) followed by quenching in water.
Hardening
Grade 309 stainless steel does not react to heat treatment. Strength and hardness of this alloy can be increased by cold working.
Grade 309 stainless steel is used in the following applications:
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