Selection Guide for Hydropower Fasteners and Seals
Graded selection by low (<50m), medium (50-200m), and high (>200m) head. 35CrMoA stud bolts with tensile strength ≥980MPa, runner bolts grade 12.9, underwater seals 316L resistant to crevice corrosion. Based on IEC 60193, ASME B16.5, and other standards.
SOLUTION COMPARISON
Selection Comparison by Head Height
Hydropower stations are classified into three levels by head height; the higher the head, the higher the strength grade and sealing performance requirements for fasteners.
| Solution | Head Range | Core Products | Corrosion Protection Grade | Standard Basis | Recommendation |
|---|---|---|---|---|---|
| Low Head Solution (<50m) | Low head small hydropower stations | 35CrMoA stud bolts M20-M36 (grade 8.8), EPDM gaskets, pressure pipe flanges PN1.0-2.5MPa | Low Low-head standard parts have large batch sizes, lowest unit cost | Freshwater environment, EPDM hydrolysis resistance lifespan ≥15 years | Run-of-river small hydropower stations, head <50m |
| Medium Head Solution (50-200m) TOP PICK | Medium head medium hydropower stations | 35CrMoA stud bolts M30-M48 (grade 10.9), PTFE+EPDM combined gaskets, pressure pipe flanges PN2.5-6.4MPa | Medium Fatigue-resistant quenching and tempering increases heat treatment cost | 35CrMoA quenched and tempered HBW240-285, yield strength ≥900MPa | Medium hydropower stations, pressure pipe and spiral case connections |
| High Head Solution (>200m) | High head large hydropower stations | 35CrMoA/42CrMo stud bolts M36-M64 (grade 12.9), 316L spiral wound gaskets, pressure pipe flanges PN6.4-10MPa | High Martensitic stainless steel vacuum heat treatment requires high equipment standards, significant premium for small batches | 316L with Mo 2-3%, pitting resistance PREN≥25, mechanical seal leakage <3ml/h | Large hydropower stations, high head impulse turbines |
The above information is compiled based on ASME B16.5, IEC 60193, IEC 60034, and publicly available industry data.
SELECTION DECISION
Detailed Hydropower Hardware Selection
The following three categories cover core fasteners and seals for hydropower stations.
01
Penstock Fasteners
Suitable for flange connections of hydropower station penstocks, withstanding water pressure of 1-10MPa
- 35CrMoA stud bolts M20-M64 (grades 8.8-12.9) + spiral wound gaskets. Preload calculated per ASME PCC-1
- 35CrMoA offers excellent fatigue resistance, suitable for long-term vibration conditions of turbines, torque wrench accuracy ±5%
Penstock FastenersSolutions →
02
Turbine Fasteners
Suitable for high-strength connections in critical parts such as turbine runners, guide vanes, and head covers
- Grade 12.9 runner bolts (40CrNiMoA) + anti-loosening washers. Tensile strength ≥1200MPa, preload up to 70% of yield
- Grade 12.9 tensile strength ≥1200MPa withstands centrifugal forces, precise preload control prevents fatigue fracture
Turbine FastenersSolutions →
03
Underwater Seals
Suitable for underwater sealing parts such as turbine shafts, manhole doors, and valves
- 316L mechanical seals (leakage <3ml/h) + EPDM/NBR/FKM gaskets. Cathodic protection + coating combined protection
- 316L with Mo resists crevice corrosion, PREN≥25, mechanical seal lifespan 3-5 years without routine maintenance
Underwater SealsSolutions →
📌 Stud bolts per ISO 898-1. Runner bolts per ISO 898-1. Underwater seals per ISO 3506-1 A4.
ELECTRICAL CONNECTORS
Full Range of Hydropower Hardware
Hydropower engineering hardware covers pressure pipeline flanges, turbine fasteners, underwater seals, gate seals, trash rack components, pumps, and more. Below are three key categories for quick selection:
Gate Seals
- Key Parameters：Gate rubber water seals (P-type/Ω-type), copper water stops, PVC water stops
- Selection Advice：For large flood discharge gates, natural rubber + P-type cross-section is recommended, with better aging resistance than nitrile rubber.
Trash Rack and Filter Components
- Key Parameters：Trash rack bolts, filter cloth clamping bolts, grid fixing parts
- Selection Advice：Trash rack bolts are long-term submerged and subject to water flow impact; 316L stainless steel is mandatory.
Pump and Auxiliary Equipment Fasteners
- Key Parameters：Pump impeller nuts, pump body connecting bolts, bearing housing bolts, cooling water pipe ferrules
- Selection Advice：Pump impeller nuts require special disassembly torque. Multi-stage pump middle section bolts must be tightened in sequence by grade.
DECISION FLOW
Hydropower Hardware Selection Process
STEP 01
Determine Head Level
Select corresponding strength grade for low (<50m)/medium (50-200m)/high (>200m)
STEP 02
Calculate Flange Load
Calculate preload per ASME PCC-1, select stud diameter and quantity
STEP 03
Select Corrosion Protection and Sealing
Choose EPDM for freshwater, NBR for oil-containing environments, FKM for high temperature and corrosion. Select 316L for crevice corrosion resistance
ENGINEERING CASES
Typical Industry Configuration Reference
The following configurations are compiled based on ASME B16.5 and typical design schemes for hydropower stations.
| Configuration Item | Typical Specification/Requirement | Design Basis/Source |
|---|---|---|
| Stud Bolt | 35CrMoA, M36×200mm, grade 10.9, yield strength ≥900MPa | ISO 898-1 |
| Runner Bolt | Grade 12.9, 40CrNiMoA, tensile strength ≥1200MPa | ISO 898-1 |
| Spiral Wound Gasket | 316L + flexible graphite, PN10.0, temperature resistance 650°C | ASME B16.20 |
| Mechanical Seal | 316L rotating and stationary rings, leakage <3ml/h, lifespan 3-5 years | API 682 |
| Manhole Door Gasket | EPDM, Φ500×10mm, hydrolysis resistant | ASTM D2000 |
| Anti-loosening Washer | M30-M64, wedge type, locking torque ≥50N·m | DIN 25201 |
⚠️ The above configurations are typical reference solutions; selection of critical components should be based on structural calculations and strength verification.
Typical Configuration List
Provide hydropower station design parameters, and we will compile a free BOM for bolts and seals—specifications and quantities of stud bolts, runner bolts, and gaskets.
Get Free BOM →Related Supporting Products
Hydropower projects may also require:
The above products are commonly used together in hydropower engineering.
TECHNICAL BASIS
Technical Basis and Reference Standards (Click to Expand)
The technical parameters on this page are compiled based on the following publicly available standards.
Fastener and Corrosion Protection Standards
- ISO 898-1:2013 — Mechanical properties of fasteners
Applicable Scope:Strength grade selection - ISO 3506-1:2020 — Stainless steel fasteners
Applicable Scope:304/316L selection - ISO 1461:2022 — Hot dip galvanized coatings
Applicable Scope:≥65/85μm grading
Hydropower Standards
- ASME B16.5-2020 — Pipe flanges
Applicable Scope:Penstock flanges - IEC 62270:2013 — Hydroelectric power plants
Applicable Scope:Automation testing - ASME B31.3-2020 — Process piping
Applicable Scope:Pipe stress analysis
Standards Inquiry
Disclaimer: Technical parameters are compiled from public standards. For specific designs, please consult a professional engineer.
FAQ
Frequently Asked Questions
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Yaxiio is an industrial hardware foreign trade procurement solutions company. We help global clients find technically compliant and cost-controllable hardware suppliers in China, providing full-process procurement services from drawing evaluation, material matching, factory audit to inspection and delivery. In the hydropower field, we deeply study key technologies such as pressure pipeline flanges, turbine fasteners, and underwater seals, systematically learning authoritative standards like ASME B16.5 and IEC 62270.