Inconel 718 Material Properties

Introduction to Inconel 718

As a leading supplier & manufacturer in China, JN Alloy supply cost-effective Inconel 718 Products. INCONEL alloy 718 (UNS N07718 / W.Nr. 2.4668) is a high-strength, corrosion-resistant nickel chromium material used at -423° to 1300°F. The age-hardenable alloy can be readily fabricated, even into complex parts. Its welding characteristics, especially its resistance to postweld cracking, are outstanding.

Inconel 718 is age-hardenable with no significant detrimental effects. One of the distinguishing features of Inconel 718’s composition is the addition of niobium to permit age hardening which allows annealing and welding without spontaneous hardening during heating and cooling. Its room temperature strength is significantly improved by precipitation heat treatment, enabling it to withstand such extreme environments. Different heat treatment solutions are required, depending on the end use of the material – the method is different for either getting the best tensile and stress-rupture properties for high-temperature applications, or for maximising the benefits for use at room or cryogenic temperatures.

One of the outstanding features of INCONEL alloy 718 is that it is extremely versatile and easy to work with. It shows excellent welding characteristics, especially with regards to its resistance to post-weld cracking. In comparison to other nickel-based superalloys, particularly those hardened by aluminium or titanium, it is vastly superior. Because it can be fabricated so readily and into increasingly complex parts, the material lends itself to high-performance applications.

Features of Inconel 718

The ease in which Alloy 718 can be fabricated offers significant benefits to the customer in terms of economy and performance. The material provides a combination of high tensile, fatigue, rupture and creep strength making it an extremely versatile alloy. Alloy 718 is used in applications ranging from simple fasteners to cryogenic tanks and rocket fuel cylinders. Alloy 718 has versatile resistance to corrosion which is outstanding, even in severely corrosive environments. The material also shows superior resistance to high-temperature effects such as oxidation and carburization. It is an excellent choice for seawater and sour gas applications.

Alloy 718 addition of Nb, Ti, Al and Ni form a series of precipitates during the controlled solution annealing and ageing process steps, resulting in a significant increase in strength and hardness compared with alternative nickel alloys. These tensile and creep rupture properties are maintained from cryogenic to elevated temperatures, making it suitable for applications between -250oC – 650oC. a nickel chromium alloy it possesses acceptable corrosion resistance in a range of environments including sea water, hydrogen sulphide, CO2, elemental sulphur and chloride ions over various temperatures. It is resistant to sulphide stress cracking and is capable of passing the sulphide stress corrosion test in accordance with NACE TM 0177 Method C solution A.

Inconel 718 is perhaps the most widely known and specified grade within this family of alloys. It was introduced in the 1960’s and initially used in the aerospace industry, but due to its ready availability in the market it was taken-up by the oil and gas industry. This was associated with wells moving offshore, drilling deeper with higher temperatures, pressures and corrosive contaminants. Other nickel-based alloys such as Hastelloy C276 and Inconel 625 provided sufficient corrosion resistance, but insufficient strength without extensive cold working. Martensitic stainless steels were limited by their potential for hydrogen embrittlement and stress corrosion cracking. Therefore, Inconel 718 quickly became a default choice for many pressure-containing and load-bearing components in aggressive environments.

Nickel alloys such as UNS N07718 are well-suited to high temperature applications as most other metals are either brittle or oxidise when exposed to elevated temperatures. However, nickel-based alloys will quickly form a protective oxide layer when heated in an atmosphere containing oxygen, thereby preventing further oxidation. It also has a relatively high melting point.

Chemical composition of Inconel 718

INCONEL 718 is made up of 50-55% nickel+cobalt (with cobalt limited to 1% max) and 17-21% chromium. This combination gives the material its corrosion-resistance properties. This includes good resistance to oxidation, enabling it to withstand corrosive media present in many of its applications. The remainder of the composition includes niobium+tantalum (4.75-5.5%), molybdenum (2.8-3.3%) and titanium (0.65-1.15%), plus other balancing elements. It’s a potent and well-balanced combination of elements, responsible for the super alloy’s desirable technical properties.The composition of the particular alloy is the following:

Products of Inconel 718

Inconel 718 offer very high levels of performance, both corrosion resistance and high strength. As such, applications will tend towards more aggressive environments as load-bearing components. The list of applications in oil and gas, plus chemical process industry, is extensive but includes wellhead and downhole components, sheathing, fasteners, gate valves, choke stems, packers, tubing hangers and other items for corrosive/sour service.

Applications of Inconel 718

Gas Turbines and Power Generation: The Inconel 718's excessive temperature resistance makes it perfect for components in gas generators, where it is able to face up to the tough conditions of combustion environments. It is likewise utilized in power era packages for additives like turbine wheels and bolts.

Oil and Gas Industry: Alloy 718 is hired in numerous oil and gasoline applications, which include downhole system, including valves, mandrels, and crowning glory gear. Its resistance to corrosion and potential to preserve mechanical homes at high temperatures make it suitable for those traumatic environments.

Medical Devices: Some scientific gadgets, specifically those requiring high strength and corrosion resistance, utilize Inconel 718. It is frequently used in implants, surgical instruments, and clinical equipment subjected to harsh sterilization techniques.

Nuclear Industry: Inconel 718 reveals packages within the nuclear industry for additives together with reactor core additives, gasoline element spacers, and manage rod power mechanisms. Its resistance to radiation-brought on damage and high-temperature balance are beneficial in those environments.

Industrial Machinery: Various business equipment and system, together with pumps, compressors, and heat exchangers, utilize Nickel Alloy 718 due to its aggregate of power, corrosion resistance, and thermal stability, especially in excessive-temperature and corrosive environments.

Additive Manufacturing: With the arrival of additive production technologies, Alloy 718 is more and more being utilized in 3-D printing packages, especially in industries requiring complicated geometries, consisting of aerospace and car.

Electronics: In sure electronics applications, mainly the ones requiring high temperature and corrosion resistance, Inconel 718 may be utilized in additives like connectors, springs, and electronic packaging.