- HIGH STRENGTH BOLTS FACTORY-HEX HEAD BOLTS MANUFACTURER
- HEAVY HEX BOLTS/STRUCTURAL BOLTS A325/STRUCTURAL BOLTS MANUFACTURER
- HIGH STRENGTH BOLTS 8.8 GRADE
- Custom bolts , Special bolts ,custom anchor bolt ,custom stainless steel ,custom fasteners
- STEEL HEX BOLTS AND NUTS AS/NZS STANDARDS /
- HS BOLT,HIGH STRENGTH BOLT BOLT FACTORY
- HEX BOLT GRADE 8.8 HDG
- HR BOLT,PRELOADBOLTS,STRUCTURAL BOLTS BS EN14399
- HEXAGON SOCKET HEAD CAP SCREWS
- HV BOLTS/EN14399-4 BOLTS/DIN6914 STRUCTURAL BOLTS.
What is the HR BOLT ?
What is the difference between HR BOLTS and HV BOLTS ?
| Bolts | Comply with BS EN 14399 – 3, adopt a long-thread design. It is required that there are at least 4 complete meshing threads to ensure that the plastic strain is not concentrated during preloading. The fillet radius under the head of the 10.9 – grade bolt is no less than 1.2mm, and the thread must be rolled. | Comply with BS EN 14399 – 4, feature a short-thread design. The thread length is about 40% shorter than that of HR bolts, which is tailored to match the thin nut structure and reduce the meshing length. | ||||||||
| Nuts | They are standard-height nuts, with a height of no less than 0.9D (D refers to the nominal diameter of the bolt). This thick nut design can match the long-thread bolt to bear a large preload. | They are thin nuts, with a height of approximately 0.8D. The thin structure enables the internal thread of the nut to achieve plastic deformation more easily when bearing load, which is the key part for the bolt assembly to realize ductility. | ||||||||
| Washers | Match EN 14399 – 5 flat washers or EN 14399 – 6 chamfered washers, with a hardness ranging from 300HV to 370HV, which can disperse the clamping force and avoid damage to the surface of the connected parts. | Specialize in pairing with EN 14399 – 6 chamfered washers. Both the inner and outer diameters of the washers are chamfered to fit the end face of the thin nut and prevent local stress concentration from causing thread stripping of the nut. | ||||||||
WHAT DOES HR MEAN ON A BOLT?
The “”HR”” marking is always paired with a strength grade (e.g., HR 8.8 or HR 10.9) on the bolt head. This combination indicates:
HR 8.8: Minimum tensile strength ≥ 800 N/mm², yield strength ≥ 640 N/mm², suitable for medium-heavy structural loads.
HR 10.9: Minimum tensile strength ≥ 1000 N/mm², yield strength ≥ 900 N/mm², for heavy-load critical connections (e.g., bridge beam-column joints, crane frames).
WHAT ARE THE MAIN APPLICATIONS FOR HR BOLT?
HR bolts (High Resistance bolts) are core components of preloaded structural fastening systems compliant with BS EN 14399, designed for heavy-load, high-reliability connections that demand rigidity, fatigue resistance, and long-term stability. Their main applications are concentrated in the following key fields:
HR bolts are the preferred fastener for critical connections in industrial and civil steel structures buildings ,some of our clients are from the steel structure industry .They are widely used in bridge engineering for components that bear heavy traffic loads and environmental stresses.Except that , HR bolts are used for critical structural connections in machinery that operates under high loads and frequent vibration,Power & Energy Infrastructure and Special Engineering Projects Hangzhou Gmetalparts served .
“If you are looking for HR bolts BS EN 14399, grade 10.9 and hot dip galvanized, please feel free to contact our export engineers at sales@gmetalparts.com We look forward to talk with you and provide most reliable solutions for your clients and projects.
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