Prestressed nuts are high-precision, micron-grade threaded fasteners made through a precision rolling process to withstand high loads and vibration environments. Its threads are formed by cold rolling, which has higher dimensional accuracy, surface finish and fatigue resistance compared to traditional cutting threads.
With the continuous distribution of metal fibers during the processing of pre-stressed nuts, the strength of pre-stressed nuts is 20%~30% higher than that of ordinary nuts, and the relaxation performance is excellent.
Prestressing nut is a supporting anchorage component specially designed for prestressed concrete rebar. Its core function is to realize high-strength connection and anchorage through precision threading with prestressed rebar, which is widely used in bridges, water conservancy projects, high-rise buildings, rail transit and other scenarios that require high structural stability.
Common materials include carbon steel, alloy steel or stainless steel, and the surface can be galvanized, nickel or Dacromet treated to enhance corrosion resistance.
Characteristics of Prestressed Nuts
- High precision and reliability: the production process of prestressed nuts is strict, with high internal thread precision and surface finish, which can effectively improve the precision and reliability of fasteners, avoiding problems such as loosening or breakage caused by mismatched threads or non-smooth surface.
- Diversified types: common prestressed nuts include common precision rolled nuts, fine thread precision rolled nuts, pressure pad type precision rolled nuts, precision rolled nuts with spacers, etc.
- Excellent mechanical properties: prestressed nuts have high tensile strength and yield strength, able to withstand large loads, and the surface has a dense layer of protective film, can effectively resist the erosion of the external environment, to extend the service life.
Difference Between Precision Rolled Nuts and Common Nuts
| Comparison Dimension | Rolled Thread Nut (Precision Nut) | Standard Nut |
|---|---|---|
| Application | Specially designed for anchoring in prestressed structures (e.g. bridges, dams); used with threaded rebar | General mechanical fastening; no specific application constraints |
| Structural Design | Available in flat type (anchorage end) and conical type (tensioning end); suitable for various engineering needs | Mostly standard hexagonal shape with simple structure |
| Material & Process | Made from 45# steel or 40Cr; heat treated to reach hardness of 28–35 HRC; high tensile strength | Made from ordinary carbon steel or low alloy steel; lower strength and corrosion resistance |
| Installation Requirements | Must be used with bearing plate and spiral reinforcement; precise control of prestressing force is required to ensure anchoring reliability | Simply screwed onto the rod; no complex installation required |
Prestressed Nut Types
By structure
- Flat Nut: Flat end face, used for bridge foundation, building structure static connection.
- Conical nuts: tapered design, enhancing the efficiency of prestressing transfer at the tensioning end. Used for dynamic anchoring of suspension bridges and tunnels.
By material
- 45# Carbon Steel Nut: Economical and practical, tensile strength ≥785MPa, suitable for ordinary water conservancy projects, conventional construction anchoring.
- 40Cr alloy steel nut: high strength and fatigue resistance, tensile strength ≥ 930MPa, suitable for cross-sea bridges, nuclear power plants and other extreme environments.
By Function
- Standard Nut: Conventional prestressing anchorage, suitable for PSB785/830 grade rebar.
- Locking nut: Built-in locking structure (e.g. double thread or nylon ring). Suitable for frequent vibration scenarios (e.g. wind turbines).
- Specified nuts: thickened type, flange one-piece type and other customized designs. Used for special connection of ultra-high-rise buildings and heavy machinery.
Prestressed Nuts Specifications
Prestressing nuts are used in conjunction with thread steel bar, Couplers, bearing plate, and spiral steel bar to form a complete anchoring system.
Thread Steel Bar Parameters
| Diameter/ mm | Grade | Nominal Area / mm2 | Weight kg/m |
|---|---|---|---|
| ∮15 | PSB830 | 177 | 1.4 |
| ∮20 | PSB500 | 314 | 2.47 |
| ∮25 | PSB500 / 830 / 930 / 1080 | 491 | 4.1 |
| ∮32 | PSB830 / 930 /1080 | 804 | 6.65 |
| ∮36 | PSB830 / 930 /1080 | 1080 | 8.41 |
| ∮40 | PSB830 / 930 /1080 | 1257 | 10.34 |
| ∮50 | PSB830 / 930 /1080 | 1963 | 16.28 |
Prestressed Thread Steel Nut Parameters
| Size | M20, M25, M32, M36, M40 |
| Surface | Epoxy coating |
Where Can I Buy High-Quality Prestressed Nuts?
BDfastener has been specialized in fasteners industry for more than 10 years, we are committed to provide customers with high quality prestressing steel nuts one-stop efficient supply service.
