Inconel 718 Material Properties

Inconel 718 is a nickel-based high-temperature alloy developed by International Nickel Company (INCO) in the late 1950s. Due to its excellent comprehensive performance, it has become a key material for components in the aerospace, energy, and petrochemical industries. Its main characteristics include:

1.High and Low Temperature Performance: It exhibits stable chemical properties and oxidation resistance within the temperature range of -250°C to 1000°C, maintaining high strength, corrosion resistance, and toughness even at 700°C. Its metallographic structure is based on austenite, with heat-treated γ-phase and δ-phase enhancing mechanical properties and plasticity, respectively, while also providing excellent weldability.

2.Corrosion resistance: excellent resistance to oxidation and corrosion

3.Heat treatment properties: Strength can be further increased by age hardening

4. Mechanical properties: high strength, good fatigue and creep properties

Inconel 718 chemical composition: nickel (50-55%), chromium (17-21%), iron (balance), niobium (4.75-5.5%), molybdenum (2.8-3.3%), etc.

Difficulties in Inconel 718 machining

 Difficulties in turning

1.High shear strength and fast work hardening speed: Inconel 718 has high shear strengteed during turning, which increases the difficulth and fast work hardening spy of cutting and requires higher cutting force and more delicate operation.

2.Low thermal conductivity: Inconel 718 has poor thermal conductivity. The heat generated during the cutting process is not easy to dissipate, which causes the temperature of the cutting area to rise, increases the speed of tool wear, and affects the processing quality.

3.High niobium content: Inconel 718 has a high niobium content. The degree of niobium segregation is directly related to the metallurgical process, which increases the difficulty of the processing and requires specific processes and technologies to ensure processing quality.

Difficulties in forging

1.Narrow forging temperature window: the temperature needs to be precisely controlled between 954-1066℃

2.Phase change sensitivity: Improper heat treatment will lead to the precipitation of δ phase, affecting performance

Inconel 718 CNC machining technology optimization

1.Tool selection: Carbide tools, ceramic tools, CBN tools and coated tools can be used for processing.

2. Cutting Parameter Optimization:

Turning: vc = 30-60 m/min, f = 0.1-0.2 mm/rev, ap ≤ 4 mm

Milling: vc = 50-80 m/min, fz = 0.05-0.15 mm/tooth

Drilling: vc = 10-20 m/min, feed 0.02-0.1 mm/rev

3. Cooling and Lubrication Strategies: High-pressure cooling (>70 bar) can effectively reduce temperatures.

MQL (minimum quantity lubrication) technology is suitable for some processes.

Inconel 718 heat treatment technology

1. Forging Process

Blank Forging: Temperature 1065-1120°C, Forging Ratio ≥ 4:1

Final Forging Temperature: No less than 954°C

Deformation Rate: A moderate rate (0.1-1s⁻¹) is preferred

2. Heat treatment specifications

Solution treatment: 955-1010°C, 1 hour/25mm, rapid cooling

Aging treatment: 720°C ± 10°C/8 hours, furnace cooling to 620°C ± 10°C/8 hours, air cooling

Advanced processing technology

Additive Manufacturing: SLM technology has been successfully applied to the manufacture of INCONEL718 parts

Key points of quality control

Surface integrity control: Appropriately reduce processing speeds to optimize cooling and avoid excessively deep work-hardened layers.

Residual stress management: Solution treat incoming material to eliminate stress and reduce excess residual stress during processing, which can cause product deformation.

NDT testing: Ensure the absence of processing defects.

Inconel 718 material application industry

Aircraft engines: turbine discs, casings, blades, etc.

 

Aerospace: rocket engine components

 

Energy equipment: nuclear power valves, turbine components

Why choose Precisionn to manufacture Inconel 718?

Precionn has extensive experience in manufacturing Inconel 718, with products ranging from oil valves to aerospace components. Our high-quality material supply allows us to forge materials of varying specifications to meet customer requirements, saving material costs and reducing machining allowances. Our years of experience in machining enable us to select appropriate tools and establish optimal machining parameters, providing high-quality products and services to the international aviation and oil industries.

Inconel 718 machining technology continues to evolve. With the emergence of new materials, processes, and equipment, machining efficiency and quality will continue to improve. Precionn will provide more reliable machining support for high-end equipment manufacturing.