Wind Turbine Bolt Induction Quenching and Tempering System

Wind Turbine Bolt Induction Quenching and Tempering System

Core Components

1. Induction Heating Unit
   • Power Supply: Medium-frequency or ultra-audio frequency power supply (IGBT modules), with a power range of 100–500kW and a frequency of 1–50kHz. It supports rapid surface heating for austenitization (850–900°C) and deep tempering (adjustable temperature: 200–600°C).
   • Heating Coils: Customized spiral or segmented coils adapt to complex bolt structures (e.g., heads and shafts), ensuring uniform magnetic field distribution and heating efficiency ≥85%.
2. Quenching Unit
   • Quenching Medium System:
     • Uses water-based quenching fluid (PAG) or fast quenching oil, applied via high-pressure spraying (5–20bar) for rapid surface cooling to form martensite (hardness: HRC 40–55).
     • Equipped with a temperature control system (accuracy ±3°C) and filtration device to maintain stable medium performance.
   • Mechanical Drive: Servo motors drive bolt rotation (50–200rpm) and axial movement (speed: 0.1–5mm/s) to ensure uniform quenching layers (hardness deviation ≤±2HRC).
3. Tempering Unit
   • Induction or Furnace Tempering:
     • Induction Tempering: Uses medium-frequency power with tempering coils for fast local or full-body tempering, reducing process time by 50% and energy consumption by 30% compared to traditional furnace methods.
     • Furnace Tempering: Box resistance furnaces or mesh belt furnaces suit mass production, with temperature uniformity of ±5°C.
   • Atmosphere Control: Optional nitrogen protection prevents surface oxidation and maintains metallic luster.
4. Control System
   • PLC+HMI: Integrates process programming, real-time data monitoring (temperature, power, flow rate, etc.), and fault diagnosis. Supports storage of multi-stage heating/cooling curves (≥100 sets of process parameters).
   • Automation Integration: Links with loading/unloading robots and conveyor lines to achieve fully automated workflows: “loading → heating → quenching → tempering → inspection → unloading,” with a production cycle of 5–15 minutes per piece (depending on bolt size).
5. Cooling and Environmental System
   • Closed-Loop Cooling: Dual-circuit water cooling (internal circulation for power supplies/coils, external circulation for quenching fluid temperature control), with water savings ≥90%.
   • Environmental Design: Quenching oil mist purification and waste medium recycling systems comply with ISO 14001 standards.

Technical Features and Advantages

1. High-Precision Process Control
   • Infrared thermometers (accuracy ±5°C) 联动闭环控制系统，dynamically adjusting heating power and cooling speed to ensure precise control of quenching layer depth (1–5mm) and tempering hardness (HRC 28–45).
   • Bolt straightness deformation ≤0.1mm/m, meeting strict assembly requirements in the wind power industry.
2. High Efficiency and Flexibility
   • Continuous production line design enables daily output of 500–2000 pieces (depending on bolt specifications), improving efficiency by 2–3 times compared to traditional batch processes.
   • Modular coils and fixtures support rapid changeovers (≤15 minutes), enabling mixed production of multiple bolt specifications.
3. Energy Savings and Reliability
   • Induction heating reduces energy consumption by 40%–60% compared to traditional furnace heating, with standby power ≤5kW.
   • Redundant designs for key components (e.g., power modules, pump sets) ensure a mean time between failures (MTBF) ≥8000 hours, supporting 24/7 operation.
4. Intelligent Traceability
   • Integrated MES system interface records real-time heat-treatment parameters (temperature, time, power, etc.) for each bolt, enabling full lifecycle quality traceability.

Typical Application Scenarios

• Applicable Bolt Types:
  • High-strength wind turbine tower bolts (grades 8.8, 10.9, 12.9);
  • Flange connection bolts, hub bolts, main shaft bolts, etc.
• Industry Standards: Complies with GB/T 3098.1, ISO 898-1, ASTM A325, and other high-strength bolt performance requirements, supporting third-party certifications like DNV GL and TÜV.

Selection Recommendations

1. Process Requirements:
   • Confirm bolt material (e.g., 42CrMo, 35CrMo), target hardness, quenching layer depth, and allowable deformation range.
   • Choose single-machine equipment for annual production below 50,000 pieces; opt for fully automated lines for large-scale production.
2. Core Configuration Priorities:
   • Power Supply: Select based on bolt diameter (e.g., ≥300kW medium-frequency power for 80mm-diameter bolts);
   • Drive Precision: Servo motors + ball screw drives ensure bolt rotation coaxiality ≤0.05mm;
   • Tempering Method: Induction tempering for high-precision needs; furnace tempering for cost efficiency.
3. After-Sales Service:
   • Choose suppliers with process debugging experience to provide trial production verification and operator training;
   • Prioritize local service teams to ensure fault response times ≤4 hours.