Hastelloy G-35
Designated as UNS N06035 or DIN 2.4643, Hastelloy G-35 is a nickel-chrimium-molybdenum alloy designed to resist “wet process” phosphoric acid, which is used in the production of fertilizers. Similar to Hastelloy G-30, G35 alloy also has excellent resistance to localized attack in the presence of chlorides, since this can be a problem beneath deposits in evaporators used to concentrate “wet process” phosphoric acid. Besides, it is much less susceptible to chloride-induced stress corrosion cracking than the stainless steels and nickel-chromium-iron alloys traditionally used in “wet process” phosphoric acid. Due to the high chromium content, Hastelloy G-35 is extremely resistant to other oxidizing acids, such as nitric, and mixtures containing nitric acid. It possesses moderate resistance to reducing acids, as a result of its appreciable molybdenum content, and, unlike other Ni-Cr-Mo alloys, it is very resistant to “caustic de-alloying” in hot sodium hydroxide.
1. Chemical Composition Requirements of Hastelloy G-35
The Chemical Composition of Hastelloy G35, % | |
---|---|
Ni | Balance |
Mo | 7.60-9.00 |
Cr | 32.25-34.25 |
Fe | ≤2.00 |
W | ≤0.60 |
Co | ≤1.00 |
C | ≤0.05 |
Si | ≤0.60 |
Mn | ≤0.50 |
V | ≤0.20 |
P | ≤0.30 |
S | ≤0.015 |
Al | ≤0.40 |
Cu | ≤0.30 |
2. Typical Physical Properties
Density | Thermal Conductivity | Specific Heat | Melting Range |
---|---|---|---|
g/cm3 | W/m.k | J/kg. k | °C |
8.22 | 10 | 450 | 1332-1361 |
3. Weldability, Heat Treatment & Workability
Gas metal arc(GMA/MIG), gas tungsten arc(GTA/TIG), and shielded metal arc(SMA/Stick) welding processes are applicable for the welding of Hastelloy G-35 alloys with relative filler metals. Hastelloy G-35 alloy can be hot forged, hot rolled, hot upset, hot extruded, and hot formed. However, it is more sensitive to strain and strain rates than the austenitic stainless steels, and the hot working temperature range is quite narrow. On the other hand, the referenced guideline of cold working is much stiffer than most austenitic stainless steels which means more energy is required during cold forming. After being worked, the alloy should be solution-annealed with the annealing temperature at 1122°C[2050°F].
4. Product Forms and Standards
Product Form | Standard |
---|---|
Sheet, Plate & Strip | ASTM B575 |
Billet, Rod & Bar | ASTM B574, B472 |
Coated Electrodes | ASTM A5.11 |
Bare Welding Rods & Wire | ASTM A5.14 |
Seamless Pipe & Tube | ASTM B622 |
Welded Pipe & Tube | ASTM B619, B626 |
Fittings | ASTM B366, B462 |
Forgings | ASTM B564, B462 |