Custom Precision Machined High-Temperature Resistant Steam Turbine Slot Nuts with Anti-Loosening Locking Design

Our custom steam turbine slot nuts are critical fastening components designed for turbine rotors, valve spindles, main steam valves, bearing assemblies, and high-pressure flanges. Manufactured from high-strength heat-resistant alloy steel using full CNC precision machining, these slot nuts are custom-made according to customer drawings, turbine parameters, and on-site operating conditions.

Featuring evenly distributed radial slots, they enable reliable locking after torque tightening, effectively preventing loosening caused by high-temperature creep, vibration, and alternating steam loads during long-term turbine operation. These components secure shaft elements, valve core parts, and rotor assemblies tightly, preventing equipment shifting, steam leakage, and unexpected unit shutdowns.

• Customizable inner thread, outer diameter, overall length, slot quantity, slot depth, step shoulder, and positioning groove to match all turbine brands
• Compatible spare parts for all steam turbines
• Support for OEM & ODM services
• Small-batch customized orders for unit maintenance and large batch orders for new power plant projects

• Optional alloy steel grades for different working temperature tiers
• Material options: 35CrMoA, 42CrMo, 12Cr1MoV, F91, F92, 17-4PH stainless steel
• High tensile strength with excellent anti-creep performance under 540℃~620℃ supercritical main steam environments
• Complete Material Test Certificates (MTC), chemical composition, and mechanical property reports supplied for power plant acceptance

• Precision thread turning with tight tolerance control for uniform stress distribution and stable pre-tightening force
• Symmetrical milling of lock slots with consistent slot size and depth for even locking effect
• Fine grinding of outer and end surfaces to eliminate burrs and reduce assembly friction
• Optional surface treatments: nitriding, hard chrome plating, black oxidation to enhance anti-rust and anti-abrasion performance

• Anti-loosening locking design: Slotted structure matches lock tabs to offset vibration and thermal deformation
• High temperature creep resistance: No permanent deformation under long-term high-pressure & high-temperature operation
• Uniform stress bearing: Prevents thread slipping, cracking, or nut failure
• Long service life: Reduces frequent replacement and maintenance downtime of turbine equipment
• Stable sealing guarantee: Prevents shaft and valve assembly displacement to minimize steam leakage risks

• Raw material incoming inspection: Spectrum analysis, hardness testing, ultrasonic flaw detection for internal defects
• Semi-finished machining inspection: Full dimensional verification via coordinate measuring machine (CMM)
• Finished product testing: Thread matching tests, slot symmetry inspection, torque simulation testing
• 100% visual appearance inspection before delivery
• Complete inspection documentation delivered with all shipments

• Supercritical & Ultra-supercritical Thermal Power Generating Units
• Industrial Cogeneration Steam Turbines
• Waste Heat Recovery Power Turbines
• Steam Turbine Retrofit & Maintenance Spare Parts
• High-pressure Main Steam Valve & Rotor Shaft Fastening Systems