Smart Axial Force Bolt Wrench HZSN-IAFW-1000

Q: Why is axial force better than torque for bolt tightening?

Torque is an indirect proxy for bolt tension. In a typical flanged joint 80% to 90% of applied torque is consumed by thread and under-head friction, so variations in lubrication, coating and surface condition produce a 30% to 50% spread in achieved preload. Measuring axial force ultrasonically closes the loop on actual bolt tension, removing that scatter.

Q: How accurate is the HZSN-IAFW-1000?

The system measures and controls axial force to 3% of full scale, sampling at 100 to 1000 readings per second, and outputs load directly in kN up to 2500 kN on bolts up to M64.

Q: Can it check bolts that are already tightened?

Yes. The system performs reverse measurement of preload on bolts that have already been tightened, which is useful for auditing existing joints and identifying under-tensioned bolts before they loosen.

Q: How many bolts can be tightened at the same time?

The unit is configurable for 2-channel or 4-channel simultaneous operation, allowing a flange bolt pattern to be tightened together for more even load distribution and shorter campaigns.

Q: Is tightening data recorded for quality assurance?

Yes. Every tightening operation is saved automatically to the built-in black-box recorder, giving a traceable quality record for each bolt, and the unit holds a remotely updatable MSD bolt library.

Quick answer

The Smart Axial-Force Bolt Wrench (HZSN-IAFW-1000) is a servo-hydraulic tightening system that measures bolt preload directly by ultrasonics instead of inferring it from torque. The operator sets a target axial force; the closed-loop servo tightens automatically to within 3% of full scale, outputting load up to 2500 kN on bolts up to M64. Because it measures real preload, it avoids the 30% to 50% scatter typical of torque-controlled tightening.

Technical Specifications

Parameter	Value
Output load	<= 2500 kN
Bolt size	<= M64
Measurement accuracy	3% F.S.
Axial-force measurement rate	100 to 1000 per second
Hydraulic drive	Servo controller + servo motor
Display terminal	Industrial rugged tablet
Data storage	120 GB
Operating temperature	-20 to 60 C
Power	220 VAC, 2.5 kW
Software	Heracles system

Overview

Torque wrenches do not measure bolt tension. They measure the torque needed to overcome friction, and in a real flanged joint most of that torque — commonly 80% to 90% — is consumed by thread and face friction rather than by stretching the bolt. Small changes in lubrication, coating, surface finish or temperature therefore produce a 30% to 50% spread in achieved preload, even when the torque wrench is perfectly calibrated and perfectly used.

The HZSN-IAFW-1000 eliminates that uncertainty by closing the loop on the quantity that actually matters. A servo controller drives a hydraulic unit while an ultrasonic axial-force measurement unit reads the bolt's elongation in real time at 100 to 1000 readings per second. Tightening stops when the measured axial force reaches the target, within 3% of full scale. The system also measures preload on bolts that are already tightened, stores all tightening data on a 64 GB built-in black-box recorder, and can be configured for two or four channels working simultaneously.

How it works

Set: the operator enters the target axial force for the bolt size and grade.
Measure: an ultrasonic probe reads bolt elongation, converted to axial force at 100 to 1000 readings per second.
Drive: a servo controller and servo motor drive the hydraulic tightening unit.
Close the loop: tightening continues until measured axial force equals target, then stops automatically.
Record: every tightening curve is stored on the built-in 64 GB black-box recorder for traceability.

Key features

Closed-loop servo control with one-key automatic tightening
3% F.S. measurement accuracy with direct kN-level axial-force output
Output load up to 2500 kN, bolt size up to M64
Configurable 2-channel or 4-channel simultaneous operation
Tightening data saved automatically with built-in 64 GB black-box recorder
Onboard MSD bolt library, remotely updatable
Reverse measurement of preload on already-tightened bolts

Applications

Tower flange and foundation bolt tightening

Achieve specified preload on large-diameter tower and foundation bolts during erection and re-torque campaigns.

Blade root bolt tightening

Replace torque-controlled tightening on critical blade-root connections where preload scatter causes loosening and bolt fatigue.

Pre-tightening verification audits

Reverse-measure existing preload on bolts already in service to identify under-tensioned joints before they loosen.

Multi-bolt simultaneous tightening

Two or four channels tighten a flange pattern at once, cutting campaign time and improving load distribution.

Frequently asked questions

Why is axial force better than torque for bolt tightening?

Torque is an indirect proxy for bolt tension. In a typical flanged joint 80% to 90% of applied torque is consumed by thread and under-head friction, so variations in lubrication, coating and surface condition produce a 30% to 50% spread in achieved preload. Measuring axial force ultrasonically closes the loop on actual bolt tension, removing that scatter.

How accurate is the HZSN-IAFW-1000?

The system measures and controls axial force to 3% of full scale, sampling at 100 to 1000 readings per second, and outputs load directly in kN up to 2500 kN on bolts up to M64.

Can it check bolts that are already tightened?

Yes. The system performs reverse measurement of preload on bolts that have already been tightened, which is useful for auditing existing joints and identifying under-tensioned bolts before they loosen.

How many bolts can be tightened at the same time?

The unit is configurable for 2-channel or 4-channel simultaneous operation, allowing a flange bolt pattern to be tightened together for more even load distribution and shorter campaigns.

Is tightening data recorded for quality assurance?

Yes. Every tightening operation is saved automatically to the built-in black-box recorder, giving a traceable quality record for each bolt, and the unit holds a remotely updatable MSD bolt library.