Aerospace-Grade Nickel Superalloy Round Bar GH4098 20mm for Turbine Discs

Engineered for high-stress aerospace environments, our 20mm GH4098 nickel-based precipitation-hardening superalloy round bar delivers exceptional yield strength, structural thermal stability, and cyclic oxidation resistance under continuous operating temperatures up to 800°C.

GH4098 (Ni-Cr-Co-Mo-W-Al-Ti system) represents an advanced solid-solution and gamma-prime (γ′γ′) precipitation-strengthened superalloy capable of maintaining structural integrity under extreme mechanical stress and corrosive combustion gas streams up to 800°C (with short-term peak capability up to 900°C).

The addition of cobalt, molybdenum, and tungsten reinforces solid-solution matrix hardness, while precisely balanced aluminum and titanium content forms a high-density, stable Ni3(Al,Ti)Ni3(Al,Ti) intermetallic phase that resists dislocation movement during high-stress thermal cycles. Manufactured under full-process inert gas protection and secondary precision hot forging/rolling, our 20mm diameter bars feature low gas content (O,N,H<15 ppmO,N,H<15 ppm), ultra-low inclusion ratings, and 100% volumetric ultrasonic integrity.

• Diameter: 20.0 mm
• Diameter Tolerance: Precision ground / peeled (h8 to h9, ±0.03 mm±0.03 mm available upon request)
• Straightness: ≤0.5 mm/m≤0.5 mm/m
• Standard Length: 2000 mm – 4000 mm (Custom cut-to-length available)
• Surface Finish: Centerless ground (Ra≤0.8 μmRa≤0.8 μm) or Bright peeled (Ra≤1.6 μmRa≤1.6 μm)

GH4098 is engineered with heavy refractory elements (Tungsten and Molybdenum) that retard grain-boundary sliding at temperatures exceeding 750°C. The alloy maintains high load-bearing endurance during prolonged high-stress exposure, significantly preventing dimensional deformation in continuous aero-propulsion cycles.

High Chromium (17.5–19.5%) and Aluminum content promotes the rapid formation of a continuous, self-healing, dense α-Cr2O3/Al2O3α-Cr2O3/Al2O3 dual oxide film on the round bar surface. This microscopic barrier prevents sulfur attack, hot combustion gas carburization, and deep intergranular oxidation.

Utilizing state-of-the-art VIM + ESR/VAR dual-melt processes guarantees minimal non-metallic inclusions and ultra-low trace impurity levels (such as Pb,Bi,Sn,Sb<10 ppmPb,Bi,Sn,Sb<10 ppm). This precise purity profile facilitates complete gamma-prime (γ′γ′) phase nucleation during solution and aging heat treatments.

Our 20mm round bars are cold-straightened and finished through high-speed centerless grinding, providing exceptional concentricity and surface uniformity. The material responds predictably to carbide and CBN CNC tooling for tight-tolerance aerospace machining.

The 20mm diameter bar stock is tailored for forging and CNC machining of small-to-medium aero-engine rotor components, compressor stator vanes, and turbine disk outer rim reinforcements where high-temperature yield strength and thermal fatigue resistance are paramount.

With high shear strength and stress-relaxation resistance at temperatures above 700°C, GH4098 round bar is widely converted into turbine casing bolts, high-pressure flange tie-rods, and aerospace threaded studs.

In land-based industrial and naval gas turbines, GH4098 provides the necessary chemical and structural stability to resist dynamic gas pulsations and aggressive hot fuel residues.

Used in rocket exhaust nozzle structural links, valve actuators, and high-pressure cryogenic-to-high-temperature transitional piping connectors.

• Integrated Superalloy Manufacturing Infrastructure: Changzhou DLX Alloy Co., Ltd. operates complete in-house vacuum smelting, electroslag refining, rapid hot forging, precision rolling, heat treatment, and bright-finishing production lines, boasting a unified monthly capacity of 1,200 tons/month.
• Zero-Defect Quality Control & Full Traceability: Every heat of GH4098 undergoes full chemical spectroscopy, high-temperature stress rupture verification, optical metallographic grain size rating (ASTM grain size equivalent control ≥6≥6), and 100% Volumetric Ultrasonic and Eddy Current Non-Destructive Testing (NDT).
• Flexible B2B Engineering Support & Dynamic MOQ: We support engineering trial orders and mass OEM volume programs with dynamic MOQ policies based on rod dimensions and heat treatment states, complete with EN 10204 3.1 chemical & mechanical inspection certificates.
• Global Export-Grade Protection & Logistics: Bars are individually surface-oiled, wrapped in vapor corrosion inhibitor (VCI) paper, packed in reinforced fumigated wooden crates or steel-framed boxes, and distributed worldwide with direct multimodal transport solutions.

A: The standard heat treatment procedure consists of solution treatment at 1100∘C−1140∘C1100∘C−1140∘C for 1 to 2 hours followed by rapid air cooling, followed by two-stage aging: 850∘C±10∘C850∘C±10∘C for 4 hours (air cool) and 750∘C±10∘C750∘C±10∘C for 16 hours (air cool) to optimize gamma-prime phase precipitation.

A: Yes. In addition to standard 20mm diameter bars, we provide diameters ranging from 8mm to 350mm. Surface options include black forged, rough turned, bright peeled, and centerless precision ground with diameter tolerances down to h8.

A: All superalloy bars are 100% evaluated using high-frequency immersion or contact ultrasonic inspection and liquid penetrant testing to ensure zero center shrinkage, pipe defects, micro-porosity, or surface fissures.

A: Standard catalog diameters in raw stock are dispatched within 10–15 business days. Custom melted heats require 30–45 days. Shipments are packaged in rust-preventative VCI material inside solid wooden cases designed for long-distance maritime and air freight.