Inconel 718
Inconel718 alloy is a precipitation hardening type nickel chromium iron alloy containing niobium and molybdenum. It has high strength, good toughness and corrosion resistance at high and low temperature when it is less than 650 degrees. The state of supply can be either solid solution or precipitation hardening.
With the following characteristics
• ease of processing
At 700 degrees centigrade, it has high tensile strength, fatigue strength, creep strength and fracture strength
• high oxidation resistance at 1000 degrees centigrade
• has a stable chemical properties at low temperatures
Good welding performance
application area
Because of its high temperature strength and excellent corrosion resistance and workability at 700 DEG C, it can be widely used in various demanding situations. Steam turbines - liquid fuel rockets
Low temperature engineering
Acid environment
Nuclear Engineering
2 chemical composition
Similar brand
GH4169, GH169 (China), NC19FeNb (France), NiCr19Fe19Nb5, Mo3 (Germany), NA 51 (UK), Inconel718, UNS, NO7718 (USA), NiCr19Nb5Mo3 (ISO)
chemical composition
Nickel, Ni, chromium, Cr, iron, Fe, carbon, C, manganese, Mn, silicon, Si, molybdenum, Mo, copper, Cu, cobalt, Co, aluminum, Al, titanium, Ti, niobium, Nb, boron, B, phosphorus, P, sulfur, S
Minimum 50172.8, 0.2, 0.65, 4.750
Maximum value 5521, allowance 0.08, 0.35, 0.35, 3.3, 0.3, 1, 0.8, 1.15, 5.50, 0.006,, 0.01, 0.01
3 physical performance editor
density
The density of =8.24g/cm3
melting range
The melting temperature range is 1260~1320 degrees C.
4 processing and heat treatment editing
Inconel718 alloys are difficult to machine materials in the field of mechanical processing.
Preheat
The workpiece must be cleaned before heating and during heating to keep the surface clean. If the heating environment contains sulfur, phosphorus, lead or other low melting point metals, the Inconel718 alloy will become brittle. Impurities come from paints, chalk, lubricating oil, water, fuel, etc., that are used for marking. Fuel sulfur content should be low, such as liquefied gas and natural gas impurities content is less than 0.1%, the sulfur content of urban gas is less than 0.25g/m3, and the sulfur content of petroleum gas is less than 0.5%, which is ideal.
Heating furnace is best to have more accurate temperature control ability, furnace gas must be neutral or weak alkaline, should avoid the furnace gas composition in oxidation and reduction of fluctuation.
Hot working
The proper hot working temperature of Inconel718 alloy is 1120-900 DEG C, and the cooling mode can be water quenching or other rapid cooling methods. After hot working, it should be annealed in time to ensure the best performance. When hot working, the material should be heated to the upper limit of the processing temperature. In order to ensure the plasticity of the processing, the final processing temperature should not be lower than 960 degrees when the deformation reaches 20%.
Cold working
Cold working should be carried out after solid solution treatment, and the work hardening rate of Inconel718 is higher than austenitic stainless steel. Therefore, the processing equipment should be adjusted accordingly, and the intermediate annealing process should be taken during the cold working process.
heat treatment
Different solution treatment and aging treatment process will yield different material properties. Because of the low diffusion rate of the gamma phase, the long term aging treatment can make the Inconel718 alloy obtain the best mechanical properties.
Polish
More difficult to remove than stainless steel in Inconel718 welding near the oxide, needs to be polished with fine emery cloth, before the mixed acid of nitric acid and hydrofluoric acid in pickling, also want to use sandpaper to remove the oxide or salt bath pretreatment.
Machining
Inconel718 machining should be carried out after solid solution treatment, taking into account the work hardening of materials, and austenitic stainless steel is different, Inconel718 suitable for low surface cutting speed.
welding
The precipitation hardening type Inconel718 alloy is suitable for welding and has no tendency to crack after welding. Weldability, workability, and high strength are some of the advantages of this material.
Inconel718 is suitable for arc welding, plasma welding and so on. Before welding, the material surface should be clean, no oil, no powder, note number, etc., within the range of 25mm around the weld to be polished, exposing the bright metal.
Inconel 718 recommended welding materials:
GTAW/GMAW
Nicrofer S 5219
W.-Nr. 2.4667
SG-NiCr19NbMoTi
AWS A 5.14 ERNiFeCr-2
BS 2901, Part, 5:, NA 5