technical of u bolt & v bolt
1. Ultimate Tensile Strength (UTS)
1. Tested as per IS 1367, ASTM A307/A325, and IS 2062.
2. V-bolts often offer higher angular grip strength due to geometry.
2. Working Load / Safe Working Load (SWL)
1. SWL is calculated with a safety factor of 2.5 to 3.0 based on UTS. This is the maximum allowable load under regular usage.
I. M10
8 – 12 kN
II. M12
12 – 18 kN
III. M16
18 – 25 kN
IV. M20
25 – 35 kN
2. SWL includes consideration for:
I. Wind load
II. Conductor sag
III. Dynamic vibrations
3. Conductor Diameter Compatibility
1. Custom sizes available to suit:
I. ACSR Weasel, Dog, Panther, Zebra
II. Stay/Guy wires
III. Pole brackets & channels
2. Often used with saddle plates or back plates for load distribution.
4. Slip Strength:
1. Critical for preventing axial movement or rotation of conductors/brackets.
2. Slip resistance is enhanced by:
I. Deep threads
II. Spring lock washers or nyloc nuts
III. Flat saddles
5. Temperature Withstanding Capacity:
1. Designed to endure extreme ambient and fault-induced heat.
2. No structural deformation or thread loss within range.
6. Corrosion Resistance:
1. U-bolts and V-bolts undergo Salt Spray Tests (ASTM B117) for coastal environments.
7. Impact & Fatigue Strength:
1. Conductor vibration
2. Torque during tightening
3. Pole sway due to wind or load shift
I. Fatigue Resistance
>10⁶ stress cycles
II. Impact Resistance
≥ 10× SWL shock load
III. Bending Strength
High (depends on thread root depth and bend radius)
4. V-bolts offer angular resistance to pole rotations or bracket slippage.
Top 5 Quality Assurance
1. Raw Material Testing
a. Tensile and hardness tests on rods
b. Chemical composition via spectro-analysis
c. Grain structure inspection (for forged bolts)
2. In-Process Quality Checks
a. Thread profile check (ISO/UN standards)
b. Torque test (30–60 Nm depending on bolt size)
c. Visual & dimensional inspection using:
I. Calipers
II. Thread gauges
III. Coating thickness meters
3. Routine Tests
a. UTS Test using Universal Testing Machines (UTM)
b. Salt Spray Test (as per ASTM B117)
c. Galvanizing Test (mass & thickness)
d. Load Cycle / Fatigue Tests
4. Certifications & Standards
a. Compliant with:
I. IS 1363 / IS 2062 / IS 2629
II. ASTM A307 / A153
III. BS EN ISO 898-1
b. Batch marking for traceability: heat no., lot no., size
c. Supplied with:
I. Test certificates (MTC)
II. Visual inspection report
III. Galvanizing certificate