Inconel718 Material introduction
Inconel718 alloy（UNS NO7718/W.Nr.2.4668）It is a nickel chromium material with high strength and corrosion resistance used between - 253 ℃ and 700 ℃. The age hardening alloy can be easily processed even if it is a complex component. Its welding performance, especially the resistance to cracking after welding, is excellent.
Inconel718 The machinability of the alloy and its good tensile, fatigue, creep and cracking strength make it widely used. For example, rings and sleeves in liquid fuel rockets, aircraft and land-based gas turbines, as well as various forms of sheet metal parts and cryogenic storage tanks. It is also used as fasteners and instrument components.
Inconel718 chemical composition
% | nickel | chromium | iron | molybdenum | niobium | cobalt | carbon | manganese | silicon | sulfur | copper | aluminium | titanium |
minimum | 50 | 17 | allowance | 2.8 | 4.75 | - | - | - | - | - | - | 0.2 | 0.7 |
maximum | 55 | 21 | 3.3 | 5.5 | 1 | 0.08 | 0.35 | 0.35 | 0.01 | 0.3 | 0.8 | 1.15 |
Inconel718 Physical and mechanical properties
density | melting point |
8.2g/cm³ | 1260-1340℃ |
varieties | Heat treatment method | tensile strength
σb/MPa | yield strength
σp0.2/MPa | Elongation
σ5 /% | Shrinkage Ψ/% | Brinell hardness HBS |
Bar | Solution treatment | 1280 | 1030 | 12 | 15 | ≥346 |
forging | Direct aging | 1280 | 1030 | 12 | 15 | 346-450 |
Inconel718 Heat treatment system
Standard heat treatment
Disk forgings, annular pieces，（950~980)℃±10℃×l h/OQ(or AC、or WQ)+720℃±10℃×8h/FC(50℃±10℃/h) →620℃±10℃×8h/AC,HB 461~341;
Forged round cake for aerospace，（950~1010)℃±10℃×l h/AC+720℃±10℃×8h/FC(50℃/h) →620℃土10℃×8h/AC(or FC)；
Silk material，955℃±10℃×l h/AC+ 720℃±10℃×8h/FC( 50℃±10℃/h) →620℃±5℃×(7~8)h／AC,HRC≥32;
Bars and forgings，（950~980)℃±10℃×l h/AC+720℃±5℃×8h/FC(50℃±10℃/h)→620℃土5℃×8h/AC,HB ≥346;
Plate and weldment：
system：（940~960）℃/AC+(710~730)℃×(8~8.5)h/FC(50℃±10℃/h)→(615~620)℃×（8~8.5) h/AC，among Solution holding time：δ(d)≤3mm，(25~30)min;J(d)3mm~5mm，(30~35)min;
systemⅡ：Intermediate annealing，（940~960)℃×(15~20)min/AC;
F)Pipe，955℃±10℃×30min/AC(Or air-cooled)+720℃±10℃×8h/FC(50℃±10℃/h) →620℃±10℃，Heat preservation time shall not be less than 18h, air cooling or air cooling.
Direct aging system for disc forgings：720℃±10℃×8h/FC(50℃±10℃/h)→620℃±10℃×8h/AC。
