Single Crystal Casting IN713LC Turbine Rotor
Introduction
Turbine rotors are central to the performance and durability of gas turbines, operating under extreme centrifugal, thermal, and mechanical loads. Conventional casting methods often introduce grain boundaries that limit fatigue and creep performance. To overcome this, single crystal casting offers a superior solution—eliminating grain boundaries and aligning grain orientation along the optimal [001] axis.
At Neway AeroTech, we specialize in the single crystal casting of critical rotating components using IN713LC, a high-performance nickel-based superalloy with excellent high-temperature mechanical properties. Our rotors are manufactured using advanced vacuum investment casting and directional solidification technologies, meeting the demands of aerospace, power generation, and defense applications.
Core Technology of IN713LC Single Crystal Turbine Rotor Casting
Wax Pattern Creation Large-format wax patterns are injected to replicate the precise geometry of turbine rotors, including hub, blades, and balance features.
Shell Mold Formation High-strength ceramic shells are built in layers (~6–10 mm thick) using slurry and refractory stucco for thermal resistance and structural integrity.
Grain Selector Integration A helical selector is included in the mold to ensure the initiation and growth of a single crystal along the [001] orientation.
Vacuum Induction Melting IN713LC alloy is melted at ~1450°C in vacuum furnaces (≤10⁻³ Pa), minimizing oxides, gas porosity, and segregation.
Directional Solidification The mold is withdrawn from the hot zone at 2–4 mm/min, forming a fully aligned single crystal rotor structure with zero grain boundaries.
Shell Knockout and Cleaning Post-casting, ceramic molds are removed by high-pressure blasting and chemical cleaning to preserve fine geometries.
Hot Isostatic Pressing (HIP) HIP is conducted at 1150°C and 150 MPa to eliminate internal porosity and enhance mechanical integrity.
Heat Treatment and Aging Rotors undergo a solution and aging heat treatment cycle to refine microstructure and optimize γ' phase distribution.
IN713LC Material Properties for Turbine Rotors
IN713LC is selected for its superior high-temperature performance, phase stability, and casting characteristics:
Maximum Operating Temperature: 982°C (1800°F)
Ultimate Tensile Strength: ≥1034 MPa
Creep Rupture Strength: ≥200 MPa after 1000 hrs at 760°C
Grain Orientation: Single crystal [001], deviation <2°
Oxidation Resistance: Excellent in turbine exhaust environments
Gamma Prime Fraction: >50% for sustained load-bearing capability
Case Study: IN713LC Single Crystal Rotor for Power Turbine
Project Background
A power equipment OEM commissioned Neway AeroTech to manufacture single crystal IN713LC turbine rotors for a high-efficiency industrial gas turbine operating continuously at 950–980°C. The goal was to achieve >20,000 operating hours with minimal deformation and high rotational balance.
Rotor Applications
Power Generation Rotors (e.g., Siemens SGT, GE LM series): Used in baseload gas turbines requiring creep and oxidation resistance.
Aerospace Engine Core Rotors: Subjected to high-speed rotation, requiring fatigue and thermal shock resistance.
Marine Propulsion Turbines (e.g., LM2500+): Operate in corrosive environments with continuous thermal cycling.
Defense Turbojet and Turbofan Rotors: Critical for mission-readiness under rapid load changes and high-G maneuvers.
Rotor Structural Features
Central bore and mounting interface for shaft integration
Airfoil roots and shrouds formed in monolithic structure
Balance holes, cooling passages, and tip seals
Complex blade profiles aligned with flow path
Manufacturing Process for IN713LC Single Crystal Rotor
Integrated Mold and Selector Design Rotor-specific wax assemblies include grain selectors, gating systems, and ceramic chill plates for optimized withdrawal control.
Vacuum Casting Execution IN713LC alloy is melted and cast in vacuum using precision-controlled directional solidification equipment.
Post-Casting HIP Treatment HIP at 1150°C/150 MPa ensures porosity-free structures and enhanced fatigue performance.
Heat Treatment Solution and aging treatment adjusts microstructure for phase stability and thermal resistance.
CNC Finishing Key surfaces are machined using superalloy CNC machining to maintain tight tolerances and rotational symmetry.
Inspection and NDT Full dimensional inspection with CMM and internal defect screening with X-ray and ultrasonic techniques.
Core Challenges in Rotor Single Crystal Casting
Avoiding stray grains in multi-blade and thick cross-section zones
Controlling cooling rates for complex geometries
Maintaining [001] orientation across varying blade lengths
Achieving balance and dimensional consistency post-solidification
Results and Verification
100% single crystal structure with confirmed [001] orientation
Grain deviation <2°, verified by EBSD
Tensile and creep performance exceeded design benchmarks
Rotor dynamic balance maintained within ±3 g·cm without correction
All parts passed NDT with zero critical defects
FAQs
Why use single crystal casting for turbine rotors?
Can IN713LC achieve sufficient performance for rotating parts?
What testing ensures rotor integrity after single crystal casting?
How is dynamic balance maintained in single crystal rotors?
What industries use IN713LC single crystal turbine rotors?
