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Customized High-strength Heat-resistant Alloy Steel Main Stop Valve Disc with Precision Hardening & Thermal-fatigue-resistant Design for Steam Turbines

Product Summary
Customized main stop valve disc for 600MW+ steam turbines. Forged from high-strength heat-resistant alloy steel, featuring precision-hardened sealing surfaces and thermal-fatigue-resistant design. Complies with DL/T 439 and GB/T 150 standards, ensuring reliability under extreme 540℃-570℃ conditions with rigorous UT/MT inspection.

Product Details

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High-strength Heat-resistant Alloy Steel Main Stop Valve Disc

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Precision Hardening Turbine Valve Disc

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Thermal-fatigue-resistant Steam Turbine Valve Disc

Material: 20Cr3MoWVA Heat-resisting Steel
Operating Temperature: 540℃-570℃
Surface Hardness: HRC 58-62
Manufacturing Standard: DL/T 439, GB/T 150
Inspection Methods: UT, MT
Dimensional Tolerance: ISO 2768-m
Product Description
Customized Steam Turbine Main Stop Valve Disc
As the master gate of turbine main-steam systems, the main stop valve performs critical functions during unit start-up, shutdown, emergency trip, and normal operation. The valve disc serves as the core component for rapid shut-off and tight sealing, directly subjected to high-temperature, high-pressure steam impact and alternating thermal-stress loads.
Our company specializes in manufacturing key spare parts for large-scale power plant steam turbines. We design and produce high-performance main stop valve discs for 600 MW and above turbine units. Manufactured in accordance with national standards including DL/T 439 Technical Specification for High-Temperature Fasteners of Fossil-fuel Power Plant and GB/T 150 Pressure Vessels, combined with extensive field overhaul experience, our products guarantee long-term reliability and safety under extreme service conditions.
Technical Features & Advantages
High-strength Heat-resistant Alloy Steel
The disc is integrally forged from premium heat-resisting steel such as 20Cr3MoWVA. It delivers outstanding high-temperature rupture strength, creep resistance, and microstructural stability for long-term service at 540℃-570℃.
Precision Hardening & Optimized Sealing Surface
Main sealing faces and pilot-valve conical surfaces undergo quenching-and-tempering, followed by surface hardening treatments including nitriding or HVOF (High-Velocity Oxy-Fuel) wear-resistant coating. Surface hardness reaches HRC 58-62, significantly improving wear-resistance and anti-galling performance.
Thermal-fatigue-resistant Structural Design
Spherical-seat matching design enables self-alignment while seating, minimizing eccentric load stress. Internal guide slots cooperate with valve-stem pins to prevent disc rotation and avoid sealing-face scratching. Built-in pilot valve balances pressure difference effectively.
Rigorous Manufacturing & Inspection
Each disc undergoes UT (Ultrasonic Testing) and MT (Magnetic Particle Testing) to eliminate internal flaws and surface cracks. Dimensional tolerance complies with ISO 2768-m, with tightly controlled geometric tolerances to achieve perfect fit against valve seat.
Application Scope
  • 600 MW, 1000 MW supercritical & ultra-supercritical steam turbine units
  • Replacement & retrofitting for HP (High-Pressure) Stop Valve
  • Spare-part replacement for planned and emergency overhaul in power plants
  • Especially suitable for operating conditions with frequent start-stop and sharp temperature fluctuation, mitigating typical failures such as thermal-stress fatigue and seal leakage
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