Home >> Application >> By Standard >> ASTM >> ASTM E-F >> ASTM E2428 Calibration of Elastic Torque Measurement

ASTM E2428 Calibration of Elastic Torque Measurement

Share:

ASTM E2428: Standard Practice for Calibration and Verification of Elastic Torque Measurement Standards 


ASTM E2428 specify the procedure for the calibration and verification of elastic torque measurement standards. 


Test Scope: 

Primary application: Calibration of static elastic torque measurement standards (not for dynamic/high-speed torque calibrations or measurements)

Key exclusion: Dynamic torque applications (e.g., impact tools, high-speed rotational systems) – results from this practice cannot be directly applied to such scenarios

Core purpose: Establish a standardized method to verify the accuracy of torque transducers used for:

    Calibrating torque testing machines (per ASTM E2624)

    Validating torque tools like wrenches (supporting ISO 6789 compliance)

    Ensuring traceability in torque measurements across manufacturing, aerospace, automotive, and metrology sectors.


Torque Test Equipment: 

Equipment TypeMinimum SpecificationsPurpose
Reference torque testerMeasurement uncertainty ≤0.5% of reading, with valid calibration certificate traceable to national/international standardsProvide the reference torque value
Loading mechanismCapable of applying torque at controlled rates (≤10 N·m/s), with coaxial alignmentEnsure uniform loading without lateral forces
Data acquisition systemResolution ≥0.1% of full scale, sampling rate sufficient to capture peak valuesRecord accurate torque measurements
Environmental controlsTemperature: 22 ±2°C (72 ±4°F), humidity: 45-55% RHMinimize environmental effects on elastic elements



Step-by-Step Test Procedure:

1. Pre-Calibration Preparation

Verify the reference torque tester's calibration certificate is current and within its validity period

Inspect the torque standard for damage, wear, or deformation that could affect accuracy

Allow the device to stabilize at ambient test conditions for ≥30 minutes

Zero both the reference tester and the torque standard to eliminate offset errors

2. Test Point Selection

Calibration must be performed at three mandatory torque levels:

20% of full scale (FS)

60% of FS

100% of FS

Optional additional points (e.g., 40%, 80% FS) may be added for enhanced characterization

3. Torque Application Protocol

Apply torque gradually and smoothly at a rate ≤10 N·m/s

For the final 20% of the range (80-100% FS), reduce the rate to ≤5 N·m/s to minimize dynamic effects

Hold each test torque for 5 seconds to allow elastic stabilization before recording

Repeat 5 times at each test point (clockwise and counterclockwise directions if bidirectional calibration is required)

Ensure no lateral forces or bending moments are applied during loading (critical for accuracy)

4. Data Collection & Analysis

Record the reference torque value and the torque standard's indicated value for each measurement

Calculate:

Average value for each test point

Deviation (indicated value - reference value)

Percent error (deviation/reference value × 100%)

Determine measurement uncertainty following GUM (Guide to the Expression of Uncertainty in Measurement) principles.


Acceptance Criteria:

Traceability: Calibration results must be traceable to SI units through a documented chain of calibrations

Uncertainty: Expanded uncertainty (k=2) of the torque standard must be ≤0.5% of reading (matching the reference tester's uncertainty)

Repeatability: Maximum variation between repeated measurements at any test point must be ≤0.2% of the reference value

Hysteresis: Difference between loading and unloading curves must be ≤0.3% of full scale (for bidirectional transducers).


Key Technical Requirements

1. Torque Rate Control

Critical parameter: Loading rate directly impacts measurement accuracy – excessive speed introduces dynamic errors in elastic elements

Standard requirement: ≤10 N·m/s for the main range, ≤5 N·m/s for the final 20%

2. Alignment Precision

Torque must be applied coaxially with the transducer's axis of rotation

Maximum allowable misalignment: 0.5° to prevent bending stresses that could affect elastic deformation measurements


Relationship to Other Standards

ASTM E2624: Directly references ASTM E2428 for calibrating torque transducers used in torque testing machine verification

ISO 6789: Relies on torque standards calibrated to ASTM E2428 for accurate hand torque tool testing (ASTM E2428 serves as the upstream standard for ISO 6789's calibration equipment)

ASME B107.300: Complements this standard for hand torque tool calibration requirements.


Core Applications & Benefits
IndustryKey ApplicationsBenefits
MetrologyCalibration of primary/secondary torque standardsEstablishes national/international reference points for torque measurements
AutomotiveValidation of torque testing machines for engine assemblyEnsures accurate bolt tightening in critical components (e.g., cylinder heads)
AerospaceCalibration of torque transducers for aircraft maintenanceMaintains safety-critical fastener integrity
ManufacturingQuality control of torque tools (wrenches, screwdrivers)Supports ISO 6789 compliance for hand torque tools

Related Standard

ISO 1174-1 Hand socket tools test standard

ISO 1174-1: Assembly tools for screws and nuts — Driving squares

Part 1: Driving squares for hand socket tools


ISO 1174-1 specifies the dimensions, separation force and designation of driving squares for hand socket tools. 

ISO 6789 Hand torque tools calibration and measurement

ISO 6789 (now split into ISO 6789‑1:2017 and ISO 6789‑2:2017) is the global standard for hand torque tools, defining conformance testing, calibration, tolerances, and marking to ensure reliable torque control in bolted connections. It applies to indicating (Type I) and setting (Type II, e.g., click) torque wrenches, covering design validation, production quality checks, and recalibration.  ISO 6789 is applicable for the step by step (static) and continuous (quasi-static) calibration of torque measurement devices, the torque of which is defined by measuring of the elastic form change of a deformable body or a measured variable which is in proportion to the torque.

ASME B107.300 Hand Torque Tools and Torque Testers

ASME B107.300 establishes dimensional, performance, safety, and marking requirements for assembly torque tools. Its core purpose is to ensure that these tools are manufactured to be strong, durable, and safe for the user, providing a minimum performance benchmark for the industry.

< Previous: ASTM E488 Test Methods for Strength of Anchors in Concrete Elements

> Next: ASTM F88 Test Method for Seal Strength of Flexible Barrier Materials

Require More Customized Solutions?

We offer customization to meet your specific needs. Our expert team will collaborate with you to develop the perfect product for you
Customize Now

Beijing United Test Co., Ltd.