Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
21CrMoV5-7 U-Bolts (EN 10269 / 1.7709) Cr-Mo-V Q+T Bolting
21CrMoV5-7 U-bolts are U-shaped bent bolts with two threaded ends, machined from EN 10269 1.7709 round bar then bent to the customer drawing. The dominant fastener for pipe-support brackets, steam-line clamps, and high-temperature exhaust-pipe mounting where the supported pipe transfers elevated temperature to the bolt.
U-Bolts Designs and Variants
Two common configurations: standard U-bolt (parallel-leg U) for round pipe and tube clamping; square-bend U-bolt for square-section steel framework clamping. Bend radius and centre-to-centre leg spacing per the customer drawing or the supported-pipe OD.
Size Range
| Configuration | Bar diameter | Centre-to-centre spacing |
|---|---|---|
| Standard U-bolt (round bend) | M12 to M48 | per pipe OD |
| Square-bend U-bolt | M12 to M48 | per beam width |
| Heavy-duty U-bolt with saddle | M20 to M64 | per drawing |
Mechanical Properties (Q+T, EN 10269)
| Property | Value | Condition |
|---|---|---|
| Tensile (Rm) | 700 to 850 MPa | RT, Q+T |
| 0.2 percent proof stress (Rp0.2) | ≥550 MPa | RT, Q+T |
| Elongation A5 | ≥16 percent | RT, longitudinal |
| Charpy V impact (KV) | ≥63 J | 20 deg C |
| 0.2 percent proof at 500 deg C | ≥450 MPa | elevated-temp |
| Hardness | 210 to 250 HBW | Q+T |
Standards Anchor
Manufactured to EN 10269 for chemistry and mechanicals. Thread to ISO 261 or ASME B1.1. Bend radius per the customer drawing with minimum bend radius equal to 2 x bar diameter to avoid bending-induced cold work degrading the Q+T mechanical floor.
Companion Hardware
Matched-grade Cr-Mo-V companions ship from the same heat lot on call-out: 21CrMoV5-7 nuts, washers, threaded rod, stud bolts and round bar.
Applications
U-bolts in 21CrMoV5-7 are specified for steam-line clamping on turbine and boiler steam piping, refinery convection-section pipe-support brackets, and petrochem reactor effluent-line clamping where the supported pipe metal temperature reaches the 21CrMoV5-7 envelope.
Inspection Documentation
Default delivery is EN 10204 type 3.1 mill test certificate with heat number, melt-shop pour record, chemistry to EN 10269 21CrMoV5-7, room-temperature tensile and 0.2 percent proof stress, elevated-temperature 0.2 percent proof at the design temperature, Charpy V impact at 20 deg C, hardness, full Q+T cycle chart and dimensional report tied to the heat lot. Type 3.2 with Lloyd's Register, DNV, BV, SGS or TUV witness inspection on call-out and standard practice on turbine and pressure-vessel procurement.
Frequently Asked Questions
Q. What is the minimum bend radius for a 21CrMoV5-7 U-bolt?
Minimum bend radius is 2 x bar diameter on inside of the bend. Below this radius the cold work induced in the bend degrades the Q+T mechanical floor and the bolt risks cracking during bolt-up or in service.
Q. Are U-bolts supplied with matching saddles and nuts?
Yes. Matched-grade hex nuts and (on call-out) load-distributing saddles or backing plates ship from the same heat lot as the U-bolt.
Q. Can you supply U-bolts to a custom drawing?
Yes. Centre-to-centre leg spacing, leg length, and bend radius per the customer drawing. Standard hex nuts in matched grade ship as companion hardware.
Q. What is the maximum bar diameter for U-bolts?
M64 in standard production; larger sizes on call-out from forged blank with custom bending and threading.
Related 21CrMoV5-7 Form Factors
Browse the full 21CrMoV5-7 form-factor range: Round Bar · Stud Bolts · Hex Bolts · Heavy Hex Bolts · Tap Studs · Body-Bound Studs · Anchor Bolts · Threaded Rod · Nuts · Washers · Forgings. Back to the 21CrMoV5-7 Alloy Hub.
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