NS336
Material Grade: NS336 Corrosion Resistant Alloy
US Grade: UNS N06625
Similar grade: Inconel 625
German grade: W.Nr.2.4610
French grade: NC22DNb
1. Overview of NS336 (Inconel625, N06625, 2.4610) corrosion-resistant alloys
NS336 (Inconel625, N06625, 2.4610) alloy is a solution-strengthened nickel-based deformed superalloy with molybdenum and niobium as the main strengthening elements, which has excellent corrosion resistance and oxidation performance, good tensile properties and fatigue properties from low temperature to 980 °C, and stress corrosion resistance in salt spray atmosphere. Therefore, it can be widely used in the manufacture of aero engine parts, aerospace structural components and chemical equipment. The alloy has good processing and welding properties, and can be supplied with a variety of plates, bars, tubes, wires, strips and forgings.
1. NS336 (Inconel625, N06625, 2.4610) alloy material grade: NS336.
2. NS336 (Inconel625, N06625, 2.4610) similar grades: GH3625 (GH625) (China), UNS NO6625 (USA), etc.
3. Technical standard
of materials 4. NS336 (Inconel625, N06625, 2.4610) alloy chemical composition: see Table 1-1.
Table 1-1%.

5. NS336 (Inconel625, N06625, 2.4610) alloy heat treatment system: Bar: 950~1030°C, air-cooled or water-cooled; or 1090~1200°C, air-cooled or water-cooled solution treatment. Plate: 950~1030°C, air cooled; or 1090~1200°C, air cooled. Pipe: recommended annealing temperature: 960~1030°C, air-cooled or water-cooled.
6. NS336 (Inconel625, N06625, 2.4610) alloy variety specifications and supply status: It can supply d25~80mm bars and δ0.8~10.5mm plates, and can also supply d6~40mm seamless (welded) pipes. The bars are not heat-treated but are delivered in polished or polished condition; The plate is supplied after solution and finishing; Tubes are supplied after solution, pickling (or bright annealing).
7. NS336 (Inconel625, N06625, 2.4610) alloy melting and casting process: The alloy is produced by vacuum induction furnace melting and electroslag remelting or vacuum induction furnace plus vacuum arc remelting process.
8. NS336 (Inconel625, N06625, 2.4610) alloy application overview and special requirements: the alloy is used to manufacture engine casings, guide vanes, mounting edges and cylinders, fuel manifolds and other parts, has passed the practical application assessment, and the maximum use temperature is 950 °C; The alloy has a certain aging hardening phenomenon after long-term use at 550~700 °C, resulting in some decline in alloy plasticity.
2. Physical and chemical properties of NS336 (Inconel625, N06625, 2.4610) corrosion-resistant alloy:
1. NS336 (Inconel625, N06625, 2.4610) alloy thermal properties:
(1) NS336 melting temperature range: 1290~1350°C^[1]。
(2) NS336 thermal conductivity: see Figure 2-1.
(3) NS336 specific heat capacity: see Figure 2-2.
(4) NS336 line expansion coefficient: see Figure 2-3.
2. NS336 density: ρ=8.44g/cm³。
3. Electrical properties of NS336 (Inconel625, N06625, 2.4610) alloy: see Figure 2-4 for alloy resistivity.

4. NS336 (Inconel625, N06625, 2.4610) alloy magnetic properties: the alloy is non-magnetic.
5. NS336 (Inconel625, N06625, 2.4610) alloy chemical properties:
(1), NS336 oxidation resistance: the alloy has excellent high temperature oxidation resistance, and the weight change of the alloy after cyclic oxidation in the air medium at high temperature is shown in Table 2-1.
Table 2-1

Note: Circulating oxidation heating for 15min and cooling for 5min is a cycle.
(2) NS336 corrosion resistance: the alloy has good seawater corrosion resistance, see Table 2-2. The alloy is also resistant to corrosion by various salt solutions. In addition, it has good resistance to nitric acid and phosphoric acid corrosion, and is also quite resistant to hydrochloric acid heated below the boiling point and sulfuric acid at low concentrations^[2]。                                            
Table 2-2

Note: Smooth specimen refers to a 6.4mm×100mm×300mm flat specimen welded with a circular weld, annealed at 980°C before welding. Specimens with gaps are bolted to the center of the deck with a 32mm fiber washer.
3. Mechanical properties of NS336 (Inconel625, N06625, 2.4610) corrosion-resistant alloy:
1. Properties specified in NS336 (Inconel625, N06625, 2.4610) alloy technical standards: see Table 3-1.
Table 3-1

(1) Standard Z9-0105-1990. (2) Standard Z9-0104-1990 and GJB 3317-1998.
4. NS336 (Inconel625, N06625, 2.4610) corrosion-resistant alloy structure:
1. NS336 alloy phase change temperature:
2. Time-temperature-microstructure transition curve of NS336 alloy
3. Microstructure of NS336 alloy: the structure of the alloy in the solid solution state is austenite matrix and a small amount of TiN, NbC, and M6C phases, and after long-term aging at 650~900 °C, the precipitated phases are γ", δ, M23C6 and M6C。 After long-term aging at 650~700 °C, the main precipitation γ", which significantly increases the strength of the alloy at room temperature and high temperature, and the plasticity decreases, but it still maintains a high level. After aging at 780~850 °C, the δ phase is mainly precipitated, although the strength is improved, but the plasticity of the alloy decreases more. There is only a small amount of precipitated phase after aging at 900°C, so the mechanical properties are similar to those of the solid solution state. The δ phase is orthogonal structure with flake Ni3Nb and exists in acicular Wechsler structure^[1,7]。
5. Process performance and requirements of NS336 (Inconel625, N06625, 2.4610) corrosion-resistant alloy:
1. NS336 alloy forming performance: The cold and hot forming properties of the alloy are good. The heating temperature of ingot forging is 1120 °C, the opening temperature is not less than 1030 °C, and the stop forging temperature is not less than 930 °C; When die forging, the final deformation should not be less than 15%~20%. The rolling heating temperature is 1120~1160 °C, the opening rolling temperature is not less than 1050 °C, the stop rolling temperature is not less than 930 °C, the deformation of the sheet cold-rolled semi-finished product is 25%~30%, and the deformation of the finished product is not less than 30%. The quenching temperature of intermediate and finished products is 1100°C±10°C^[1,8]。
2. NS336 alloy welding performance: The alloy has good welding performance, and can be used for argon arc welding with tungsten electrode or this alloy as an additive under the protective atmosphere, and can also be brazed and welded by resistance seam.
3. NS336 alloy parts heat treatment process: stress relief: 900°C; Annealing: 930~1040°C, 1h; Solution treatment: 1090~1200°C, air-cooled or water-cooled. When the alloy works at no higher than 650°C, the material in the hot-rolled, cold-rolled or annealed state can be used on request. When the working temperature is above 650 °C, the annealing process can be used for parts that require good fatigue properties and tensile strength, and solution treatment can be used for parts that require good creep and durability.
4. NS336 surface treatment process: When removing the oxide scale on the alloy surface, alkali wash first, and then pickling in nitric acid-hydrofluoric acid-aqueous solution.
5. NS336 cutting and grinding performance: cemented carbide or high-speed steel tools should be used. The cutting tool used should have a positive rake angle. Water-based coolant is recommended for high-speed cutting, and viscous coolant is recommended for low-speed cutting.
6. NS336 (Inconel625, N06625, 2.4610) corrosion-resistant alloy varieties specifications and supply status
1. Variety classification: NS336 seamless pipe, NS336 steel plate, NS336 round bar, NS336 forging, NS336 flange, NS336 ring, NS336 welded pipe, NS336 steel belt, NS336 wire and supporting NS336 welding consumables.
2. Delivery status: seamless tube: solid solution + acid white, length can be fixed; Plates: solid solution, pickling, trimming; Welded pipe: solid solution acid white + RT% flaw detection, forgings: annealing + polishing; The bar is in a forged state, the surface is polished or polished; The strip is delivered by cold rolling, solution soft state, and descaling; The filaments are delivered in solution pickled discs or straight strips, solution straight strips in finely polished condition.