Alloy 329 ( also called AISI 329 and Alloy 329) is a stainless, acid resistant, duplex steel with improved machinability. Since the steel is machinability improved, it is suitable for production of details with comprehensive machining. The steel has very good corrosion resistance particularly in chloride-bearing environments and is extra resistant to pitting corrosion, crevice corrosion, stress corrosion cracking and corrosion fatigue. It also has high strength and toughness.
| Zeon Grade | Alloy Name | UNS | EN / DIN / W Nr. | AISI / ASTM | Trademarks |
|---|---|---|---|---|---|
| Zeon52 | Alloy 329 | UNS S32900 | 1.4460 | F52 | 10RE51 |
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N |
|---|---|---|---|---|---|---|---|---|---|
| Alloy 329 (UNS S32900) | ≤ 0.05 | ≤ 2.0 | ≤ 1.0 | ≤ 0.035 | ≤ 0.030 | 25.5 | 1.5 | 5 | 0.08 |
| Grade | Density (kg/m3) | Elastic Modulus (GPa) | Mean Co-eff of Thermal Expansion (μm/m/°C) | Thermal Conductivity (W/m.K) | Specific Heat 0-100°C (J/kg.K) |
Electrical Resistivity (nΩ.m) |
||
|---|---|---|---|---|---|---|---|---|
| 0-100°C | 0-315°C | 0-538°C | ||||||
| Alloy 329 (UNS S32900) | 7.8 | 200 | 13.0 | 14.0 | - | 15 | 500 | 0.8 |
| Grade | Tensile Str (MPa) min |
Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
|---|---|---|---|---|---|
| Rockwell C (HR C) | Brinell (HB) | ||||
| 329 | 620-800 | 450 | 20 | - | 260 max |
| Corrosion Resistance Properties of Alloy 329 |
|---|
Alloy 329 shows very good corrosion resistance particularly in chloride-bearing environments. Its resistance to chloride caused attacks such as pitting, crevice corrosion, stress corrosion and corrosion fatigue is much better than that of fully austenitic stainless steels of EN 1.4404 type. Also, in most cases EN 1.4460 is much better than EN 1.4404 type with regard to general corrosion resistance in reducing and oxidizing acids. Besides the two-phase microstructure and the low carbon content render EN 1.4460 better resistance to intercrystallite corrosion after sensitization within the temperature interval 500 - 900º C. When extremely high demands are imposed on resistance to pitting and crevice corrosion it is recommended that machining of the steel surface be followed by pickling or passivation. |
| Heat Treatment | Solution annealing 1020 - 1100ºC. Holding time at solution annealing temperature approx. 30 min, followed by rapid cooling in water. Stress relief treatments can in special cases be performed at 550ºC - 600ºC. |
|---|---|
| Welding | Alloy 329 possesses good weldability and can be welded in the same manner as austenitic material. Welding should be carried out without preheating and with small weld beads, i.e., with as little heat supply as possible. It is not necessary to use welding consumables of the same steel grade but also austenitic ones can be used. Welding of EN 1.4460 and subsequent application in highly corrosive environments could lead to a reduction in corrosion resistance. After annealing at 980° C and quenching in water the corrosion resistance of the weld will be just as high as that of the base material. |
| Machinability | Alloy 329 is a machinability improved Duplex stainless steel, which has considerably better machinability properties then EN 1.4462 It is not a ” stainless free cutting steel ” but a high class norm steel. It is an” easy to machine steel”, considered for parts where extensive machining is required. |
| Fabrication | Hot and cold forming Hot forming should be carried out in the temperature range 1200-950° C. It should however, be observed that the strength of the duplex material is low at high temperatures. Hot working should normally be followed by solution annealing. Due to the high proof strength of duplex material, greater working forces than those required for austenitic steel are usually needed for cold forming of duplex steel. The spring back is relatively high because of the high yield point. Solution annealing is normally recommended after more than 10 % cold deformation. |
| Applications Of Alloy 329 | |||
|---|---|---|---|
| Gas Processing Industries | Petro chemical industries | chemical Industries | Oil & Gas Industries |
| Power Generation Industries | Fertitdzers Industries | Sugar Industries | Food Processing Industries. |