Inconel625
Commercial grade: Inconel625?Nickel-based high-temperature alloys
U.S. grade: UNS?N06625
Chinese grade: GH3625/GH625
French grade: NC22DNb
Germany grade: W.Nr. 2. 4856
Overview of Inconel625 (NO6625) high temperature alloy:
Inconel625 is a solid solution strengthened nickel-based deformation of high temperature alloys with molybdenum, niobium as the main strengthening elements, with excellent corrosion resistance and oxidation resistance, good tensile properties and fatigue properties from low temperatures up to 980 ° C, and resistance to salt spray atmosphere under the Stress corrosion. Therefore, can be widely used in the manufacture of aircraft engine parts, aerospace structural components and chemical equipment. The alloy has good processing and welding properties and can be supplied in a variety of plates, bars, tubes, wires, strips and forgings.
1, material grade:?Inconel625.
2, Inconel625 similar grades:?GH3625 (GH625) (China), UNS NO6625 (U.S.), NC22DNb (France), 2.4856 (Germany).
3, chemical composition: see table 1-1.
4, heat treatment system: bar: 950 ~ 1030 ℃, air-cooled or water-cooled; or 1090 ~ 1200 ℃, air-cooled or water-cooled solution treatment. Plate: 950 ~ 1030 ℃, air cooling; or 1090 ~ 1200 ℃, air cooling. Pipe: recommended annealing temperature: 960 ~ 1030 ℃, air-cooled or water-cooled.
5, varieties and specifications and state of supply: can supply d25 ~ 80mm bar and δ0.8 ~ 10.5mm plate, can also supply d6 ~ 40mm seamless (welded) pipe. Bars are not heat-treated but delivered in turned or polished condition; plates are supplied after solid solution and finishing; pipes are supplied after solid solution and pickling (or bright annealing).
6, melting and casting process: the alloy is produced by vacuum induction furnace melting and electroslag remelting or vacuum induction furnace and vacuum arc remelting process.
7, application profile and special requirements: the alloy is used in the manufacture of engine magazines, guiding blades, mounting side and barrel, fuel manifold and other parts, has been through the practical application of the assessment, the maximum operating temperature of 950 ° C.; alloy in the 550 ~ 700 ° C long-term use of aging hardening phenomenon, resulting in some decline in the alloy's plasticity.
Two, Inconel625 (NO6625) high-temperature alloy physical and chemical properties:
1, thermal properties:
(1), Inconel625 melting temperature range: 1290 ~ 1350 ℃ [1].
(2), thermal conductivity: see Figure 2-1.
(3), specific heat capacity: see Figure 2-2.
(4), coefficient of linear expansion: see Figure 2-3.
2, Inconel625 Density: ρ = 8.44g/cm3.
3, Inconel625 Electrical Properties: alloy electrical resistivity see Figure 2
4. 4, Inconel625 magnetic properties: the alloy is non-magnetic.
5, Inconel625 chemical properties:
(1), Inconel625 antioxidant properties: the alloy has excellent resistance to high-temperature oxidation properties, high temperature in the air medium cyclic oxidation of the alloy after the weight change is shown in Table 2-1.
Note: cyclic oxidation heating 15min, cooling 5min for a cycle.
(2), Inconel625 corrosion resistance: the alloy has good resistance to seawater corrosion, see Table 2-2. alloy is also resistant to corrosion of various salt solutions. In addition, there is good resistance to corrosion of nitric and phosphoric acid, the heating to the boiling point of the following hydrochloric acid and low concentrations of sulfuric acid corrosion also has considerable resistance.
Note: The smooth specimen refers to the 6.4mm x 100mm x 300mm flat specimen welded with a circular weld seam, annealed at 980°C before welding. The specimen with seam is the specimen with 32mm fiber washer bolted to the center of the plate.
Three, Inconel625 (NO6625) high-temperature alloy mechanical properties:
Inconel625 technical standards stipulate the performance:? See Table 3-1
①? Standard Z9-0105-1990. ? ② standard Z9-0104-1990 and GJB 3317-1998.
Four, Inconel625 (NO6625) high-temperature alloy organization and structure:
1, Inconel625 phase transition temperature
2, Inconel625 time-temperature-organization transformation curve?
3, Inconel625 alloy structure: the alloy in solid solution state of the organization for the austenite matrix and a small amount of TiN, NbC, and M6C phase, the precipitation of the phase after long-term aging by 650 ~ 900 ℃, the precipitation of the phase for the γ "?, ?, M23C6 and M6C. In 650 ~ 700 ℃ long-term aging of the precipitation of γ "?, so that the alloy room temperature, high-temperature strength After aging at 650～700℃, γ" is mainly precipitated, so that the room temperature and high temperature strength of the alloy is significantly increased, and the plasticity decreases, but still maintains a high level; after aging at 780～850℃, δ phase is mainly precipitated, and the alloy's plasticity decreases more although the strength is increased; after aging at 900℃, there is only a small amount of precipitated phases, so the mechanical properties are similar to those of the solid solution state; the δ phase is an orthorhombic structural lamellar Ni3Nb, and exists in the form of acicular Weil's body organization [1,7].
Fifth, Inconel625 (NO6625) high temperature alloy process performance and requirements:
1, Inconel625 molding properties:
The alloy's hot and cold forming properties are good. Ingot forging heating temperature of 1120 ° C, open forging temperature is not less than 1030 ° C, stop forging temperature is not less than 930 ° C; die forging, the final deformation should be not less than 15% to 20%. Rolling heating temperature of 1120 ~ 1160 ℃, open rolling temperature of not less than 1050 ℃, stop rolling temperature of not less than 930 ℃, sheet cold rolling semi-finished products deformation of 25% ~ 30%, finished products deformation of not less than 30%. Intermediate and finished product quenching temperature of 1100 ℃ ± 10 ℃ [1,8].
2, Inconel625 welding performance:
Alloy welding performance is good, can be in a protective atmosphere with tungsten electrode or this alloy as additive for argon arc welding, can also be used for brazing connection and resistance seam welding.
3, Inconel625 parts heat treatment process:
Stress relieving: 900 ℃; annealing: 930 ~ 1040 ℃, 1h; solution treatment: 1090 ~ 1200 ℃, air or water cooling. When the alloy is working at not higher than 650℃, the material can be used in hot rolled, cold rolled or annealed condition according to the requirements. When the working temperature is above 650 ℃, the requirement of better fatigue properties and tensile strength of the parts can be used annealing process, the requirement of better creep and durability of the parts can be used solution treatment.
4, Inconel625 surface treatment process: remove the surface of the alloy oxide skin first alkaline wash, and then in the nitric acid - hydrofluoric acid - water solution pickling.
5, Inconel625 cutting and grinding performance:
Carbide or high-speed steel tools should be used. The cutting tool used should have a positive front angle. Water-based coolant is recommended for high-speed cutting and processing, and a more viscous coolant is recommended for low-speed cutting and processing.