Quick Answer
UTM calibration at Prism (NABL CC-2480) covers force measurement accuracy (per ISO 7500-1), crosshead speed/displacement, and extensometer calibration. We calibrate UTMs from 1 kN to 2000 kN capacity, issuing NABL certificates for material testing labs across Gujarat.
Key Takeaways
- UTM calibration per ISO 7500-1:2018 covers force measurement at 5 points across the machine range.
- Force accuracy classes: Class 0.5 (±0.5%), Class 1 (±1%), Class 2 (±2%).
- Crosshead speed and displacement must also be calibrated for accurate strain measurement.
- Extensometer calibration is separate — covered by ISO 9513.
- Prism calibrates UTMs from 1 kN to 2000 kN (200 tonnes) capacity.
Why UTM Calibration Matters for Gujarat Industries
A Universal Testing Machine that reads 5% high will report higher tensile strength than actual — steel components will appear to pass specifications when they do not. This has catastrophic consequences in automotive, construction, and pressure vessel applications. ISO 7500-1 requires UTMs used for material certification to be calibrated by accredited labs at least annually.
UTM Calibration Procedure (ISO 7500-1)
Reference Transducer
Install calibrated NABL-traceable reference force transducer (Wheatstone bridge type) inline with UTM load cell.
5-Point Force Calibration
Apply force at 20%, 40%, 60%, 80%, 100% of UTM's rated capacity (in tension and compression if applicable).
Error and Classification
Calculate error at each point. Classify accuracy: Class 0.5, 1, 2 per ISO 7500-1 based on measured accuracy.
Crosshead Speed Verification
Verify crosshead displacement speed at 2–3 set speeds using calibrated encoder or laser displacement sensor.
Extensometer Calibration
Calibrate extensometer using gauge length standards per ISO 9513. Verify gauge length, displacement accuracy, and linearity.
NABL Certificate
Issue NABL certificate for force accuracy class, crosshead speed accuracy, and extensometer (separate certificate).
Industries Using UTMs in Gujarat
- Steel rolling mills and re-bar manufacturers (mechanical property testing)
- Rubber and polymer manufacturers (tensile, elongation testing)
- Automotive component manufacturers (seat belt webbing, springs, fasteners)
- Textile mills (yarn and fabric tensile strength)
- Plastics industry (film tensile, flexural, impact)
- Construction (rebar, wire, structural steel certification)
- Packaging industry (carton compression, film peel strength)
Frequently Asked Questions
What is the difference between UTM calibration and UTM verification?
Calibration (per ISO 7500-1) quantifies the UTM's force measurement error with traceability and uncertainty. Verification is a simpler pass/fail check. For material certification and accreditation, calibration per ISO 7500-1 is required.
How accurate should a UTM be for material testing?
For structural material certification (steel, aluminium), UTM accuracy class 1 (±1%) is typically required. For precision elastomer and polymer testing, Class 0.5 (±0.5%) is preferred.
Does Prism calibrate UTMs at client site?
Yes. UTMs are calibrated on-site using portable reference force transducers, as they cannot be transported to a lab. Prism's engineers carry NABL-calibrated reference transducers to customer sites across Gujarat.
Can Prism calibrate UTMs above 500 kN capacity?
Yes. Prism calibrates UTMs up to 2000 kN (2 MN) using high-capacity NABL-calibrated reference force transducers.
Is UTM calibration required for BIS (Bureau of Indian Standards) testing labs?
Yes. BIS (IS 1608, IS 1757, IS 1947 series) material testing standards require UTMs to be calibrated per ISO 7500-1 by NABL-accredited labs.
Written by
Er. Parthiv Kinariwala
Managing Director · Prism Calibration Centre · NABL CC-2480 · Ahmedabad
Er. Parthiv Kinariwala founded Prism Calibration Centre in 2004 and has over 20 years of hands-on experience in calibration engineering, NABL accreditation, and industrial compliance. His team performs 10,000+ calibrations annually from the Vatva GIDC laboratory, serving 5000+ industries across Gujarat.
Prism Calibration Centre — Vatva GIDC, Ahmedabad
Prism Calibration Centre
F-101, Rudraksh Complex 2, Phase 3, GIDC Vatva, Near Jasoda Nagar Cross Road, Ahmedabad — 382445, Gujarat, India
Phone: +91 98245 26444
Email: info@prismcalibration.com
NABL: CC-2480 · ISO/IEC 17025:2017
Hours: Mon–Sat, 9:00 AM – 7:00 PM