Nimonic 90/UNS N07090/W. Nr. 2.4632/Alloy 90 bar

Nimonic 90 bar, designated as UNS N07090 and material number W.Nr. 2.4632, is a precipitation-hardenable nickel-chromium-cobalt superalloy strengthened by aluminum and titanium. It is an enhanced version of Nimonic 80A, with the addition of cobalt to improve high-temperature strength and creep resistance. This bar stock form is designed for demanding service at temperatures up to approximately 920°C (1690°F) and is a critical material for machining and forging high-stress components such as turbine blades, vanes, discs, and fasteners in aerospace and industrial gas turbines.

Introduction to Nimonic 90 (Alloy 90)

Nimonic 90 represents an advancement in the Nimonic alloy series, offering superior high-temperature capabilities compared to Nimonic 80A. The addition of cobalt provides significant solid-solution strengthening and improves the alloy’s structural stability under prolonged thermal exposure. The bar stock achieves an excellent balance of high tensile and creep-rupture strength, good fatigue resistance, and oxidation resistance. It is a premier choice for rotating and static parts in the hot sections of gas turbine engines where reliability under extreme conditions is paramount.

Chemical Composition of Nimonic 90 Bar

The enhanced properties of Nimonic 90 bar are a result of its optimized composition, which includes cobalt for elevated temperature performance. Supplied by Shanghai NC Metal Materials Co., Ltd., the bar stock meets exacting aerospace specifications.

Mechanical Properties of Nimonic 90 Bar (Heat Treated)

The mechanical properties of Nimonic 90 bar are developed through solution treatment and aging, resulting in high strength suitable for the most demanding turbine components.

Typical Value (Aged Condition)

Physical Properties of Nimonic 90 Bar

The physical properties of Alloy 90 are consistent with high-performance nickel-based superalloys.

Notes / Condition

Standard Specifications, Bar Forms, and Available Sizes

Shanghai NC Metal Materials Co., Ltd. supplies Nimonic 90 bar primarily as forging billet and bar for high-integrity aerospace components.

Primary Applications of Nimonic 90 Bar Stock

Machined or forged components from Nimonic 90 bar are essential in the hottest and most highly stressed parts of turbines: Aerospace Gas Turbines: High-pressure turbine blades, vanes, discs, and seals in both military and commercial jet engines. Industrial Gas Turbines: Turbine blades, discs, and bolting for land-based power generation units. High-Temperature Fasteners: Bolts, studs, and nuts used in turbine assembly and other high-temperature structures. Automotive & Racing: Turbocharger turbine wheels and components for extreme performance applications.

Heat Treatment

Nimonic 90 requires a precise heat treatment to develop its optimal high-temperature properties: Solution Treatment: Typically performed at 1080°C (1975°F), holding, followed by rapid cooling (air quench). This dissolves the γ’ forming elements and homogenizes the structure. Aging Treatment: A two-stage aging process is often used for optimal properties, e.g., 700°C for 16 hours, then air cool. This precipitates a fine, uniform dispersion of the strengthening gamma prime (γ’) phase. Bar and billet are often supplied in the solution-treated condition for subsequent forging or machining, with aging as the final step.

Machining and Fabrication

Machining Nimonic 90 bar is challenging and is best performed in the solution-annealed condition before final aging. It is a tough, strong alloy with a high work-hardening rate. Successful machining requires: extremely rigid machine tools; premium-grade carbide or ceramic cutting tools; low to moderate cutting speeds; consistent feed rates; and high-pressure coolant to control heat and work hardening. Machining in the fully aged condition is significantly more difficult. The alloy is forgeable within a specific temperature range (1050-1150°C) but requires careful control.

Welding Characteristics

Nimonic 90 has limited weldability. Like other precipitation-hardened superalloys, it is susceptible to strain-age cracking and liquation cracking in the heat-affected zone (HAZ). Welding, if absolutely necessary, should be performed in the solution-annealed condition using matching filler metals and with strict control over heat input and interpass temperature. A full post-weld heat treatment (solution treat + age) is mandatory to restore properties, but this is often impractical. For critical rotating components like turbine blades, welding is generally avoided in favor of integral machining or casting.

Reference Pricing and Key Purchasing Factors

The price of Nimonic 90 bar from Shanghai NC Metal Materials Co., Ltd. is significantly influenced by its high cobalt content, placing it in a higher cost category than cobalt-free grades like Nimonic 80A.