HotSense Time-Of-Flight-Diffraction (TOFD) – Ionix Advanced Technologies

HotSense™ Time-Of-Flight-Diffraction (TOFD)

Minimise operational risk and maximise productivity with on-stream asset intelligence with continuous use temperature of -55 to +350°C

Time-of-flight diffraction transducers for on-stream weld root corrosion and crack/defect detection for use in applications across refining, oil & gas, energy, nuclear, aerospace, and process sectors.

OUR TECHNOLOGY

Built on the award winning HotSense^™ ultrasonic platform powered by the proprietary Ionix HPZ piezo-ceramic, and offering increased heat resilience.
-55 to +350 °C [-67 to +662 °F] continuous use temperature range.
No cooling required. Increase your productivity by reducing duty cycling.
High sensitivity with integrated wedges across the temperature range.
Compatible with commercial scanners and crawlers.

$HotSense High Temperature Time of Flight Diffraction (TOFD) Probe$

ADVANTAGES

Stable signal for reliability and repeatability – no duty cycling means no drift from thermal gradients in the wedges.
Short approach to beam exit to get closer to weld caps.
Enhanced wear resistance for the most extreme environments and applications.

For more information contact us

TECHNICAL DETAILS

Make weld inspections on hot assets, on-stream, without the need to shutdown or isolate.
Make effective weld root corrosion assessments rapidly at high-temperature.
Detect and size cracks or defects in welds or parent material on-stream.
Screen for HTHA in-service.
TOFD carries the highest POD for NDT methods.

TOFD KIT

Be ready for any weld inspection with a complete set of HotSense™ Time-of-Flight Diffraction (TOFD) transducers for on-stream inspection of a wide range of welds, depths and vessel diameters.

Complete set of HotSense™ TOFD probes (24 probes) with integrated 50, 60 and 70˚wedges with flat, 8”, 12” and 16” profiles to cover pipe diameters from 6″ NPS to flat.
Includes high-temperature couplant feed tubing, splitters and high-temperature cables.
HotSense™ TOFD protective case with cut-outs for 24 HotSense™ TOFD Probes, cables and accessories.

Download full datasheet here.

CASE STUDIES

TECHNICAL NOTE | Enhancing high-temperature PAUT and TOFD inspection for weld root erosion

17 September 2025

TECHNICAL NOTE | High-Temperature Weld Root Corrosion Inspection

27 May 2025

CASE STUDY | In-process weld repair of ammonia converter with HotSense™ TOFD

28 January 2025

CASE STUDY | High-temperature TOFD for high-pressure steam lines

11 November 2024

Application Note – High-Temperature Weld Root Corrosion Inspection

4 May 2023

Application Note – High-Temperature TOFD Inspection of Carbon Steel Weld

4 May 2023

High-temperature TOFD trial

17 March 2023

High-temperature TOFD inspection of carbon steel weld

17 March 2023

TRANSDUCER SPECIFICATION

Parameter	Value	Unit
Surface temperature range*	-55 to +350 / [-67 to +667]	°C / [ °F]
Refracted Beam	50, 60 and 70, longitudinal at 200 °C / 392 °F *	degrees
Wedges	Engineering polymer in steel, integrated Profiled on request	mm / [in]
Connector type	Lemo 00	-
Pivot pins	5 mm pins as standard **	-
Couplant nozzles	to fit 4 - 4.5 mm tubes	-
Ruggedisation	Designed to meet IP 65 Stainless steel construction	-
Acoustic characteristics certificate of conformity to ISO 22232-2 supplied with each unit
Transducer centre frequency	5.0 at 50 & 60 deg wedge angle 6.0 at 70 deg wedge angle	MHz
Active element diameter	6.0	mm
Beam exit distance from edge	1.5	mm

Parameter	Value	Unit
Surface temperature range*	-55 to +350 / [-67 to +667]	°C / [ °F]
Refracted Beam	50, 60 and 70, longitudinal at 200 °C / 392 °F *	degrees
Wedges	Engineering polymer in steel, integrated Profiled on request	mm / [in]
Connector type	Lemo 00	-
Pivot pins	5 mm pins as standard **	-
Couplant nozzles	to fit 4 - 4.5 mm tubes	-
Ruggedisation	Designed to meet IP 65 Stainless steel construction	-
Acoustic characteristics certificate of conformity to ISO 22232-2 supplied with each unit
Transducer centre frequency	5.0 at 50 & 60 deg wedge angle 6.0 at 70 deg wedge angle	MHz
Active element diameter	6.0	mm
Beam exit distance from edge	1.5	mm

Compatible with UT flaw detectors and scanners
*Refracted angle temperature dependence on steel
**Other variations available via special request
For couplant, cables accessories and other specifications please contact our sales team

HotSense™ UT

UT Accessories

High Temperature Masterclass

High performance dual UT tranducers

550 °C +

Thickness, corrosion and erosion surveys

High temperature couplants

Cables

Guards and more

Perform pre-shutdown inspections

Make safe and reliable measurements

Expand your service offering

HotSense™ UT
High performance dual UT tranducers
550 °C +
Thickness, corrosion and erosion surveys

UT Accessories
High temperature couplants
Cables
Guards and more

Web Page: HotSense-UT-Probes-White-Background

High Temperature Masterclass
Perform pre-shutdown inspections
Make safe and reliable measurements
Expand your service offering

TOFD FAQ

What is Time of Flight Diffraction (TOFD) testing?

Time of Flight Diffraction (TOFD) testing is an advanced ultrasonic non-destructive testing (NDT) technique used to inspect and evaluate the integrity of materials, primarily weld defects, flaws, and cracks.

TOFD works by sending ultrasonic waves into the material being tested from a transmitting transducer. These waves travel through the material until they encounter a change in the material’s structure, such as a crack, void, or weld defect. When the ultrasonic waves interact with these changes, they produce diffraction, which is detected by the receiving transducer.

TOFD offers the highest probability of detection for UT methods and is a sensitive and accurate location and sizing tool of defects due to the measurement of time-of-flight rather than amplitude from diffraction of crack tips.
What is the difference between TOFD and Ultrasonic Testing (UT) methods?

TOFD is a specific ultrasonic testing technique that excels in the detection and characterization of planar defects like weld flaws and cracks. Conventional UT methods are more versatile and can be applied to a broader range of testing scenarios, including thickness measurements and general flaw detection. The choice between TOFD and conventional UT depends on the specific requirements of the inspection and the types of flaws one needs to detect and characterize.
Is TOFD only suitable for weld inspection?

While Time of Flight Diffraction (TOFD) is commonly used for weld inspection, it is not limited to this application. TOFD can be used for a wide range of non-destructive testing (NDT) and inspection purposes in addition to weld inspection, including corrosion and defect detection. Some of the other industries where TOFD can be applied include piping inspection, pressure vessel inspection, aerospace, power generation, structural inspection, manufacturing and nuclear.

While TOFD is versatile, it’s essential to choose the most appropriate non-destructive testing technique for a specific application, considering factors such as the type of material, the nature of the defects of interest, and the available equipment. Speak to an Ionix expert to find out which technique will be most suitable for your application: contact@ionix.at
What thickness gauges and flaw detectors are compatible with the TOFD Transducers?

Our inspection probes are compatible with all standard ultrasonic thickness gauges and flaw detectors that can display an A-scan and B-scan. See international standards ISO 16282 for more information on equipment selection.

The Ionix probes have Lemo 00 type connectors as standard which can be used with any compatible cable to provide connections to your unit.
What do the different size wedges mean?

Time of Flight Diffraction (TOFD) uses specialized wedges, to generate and receive longitudinal ultrasonic waves for flaw detection and sizing. These TOFD wedges come in various angles and configurations, and the choice of wedge size is important for optimizing the inspection process. Here’s what different size TOFD wedges are and what they mean:

70 deg, 6 MHz probe – The higher frequency improves the resolution and high nominal probe angle helps to reduce the dead zone near the surface. Recommended for wall thickness from 6 to 25 mm*

60 deg, 5 MHz probe – Balancing detection resolution and depth of penetration across the temperature range. The nominal probe angle of 60° make it suitable for wall thickness from 15 mm to 35 mm*.

50 deg, 5 MHz probe – The lowest probe angle makes it suitable for thicker parts.

*Wall thicknesses are given as guidance only for parent material and will depend on frequency, angle, surface roughness, temperature and other factors. A validation should always be completed prior to measurement. For welds, see ISO 10863 and ISO 16828 for guidance.
I want to detect cracks at an ambient temperature, is this possible?

HotSense TOFD is not only suited for high-temperature applications. It exhibits remarkable sensitivity in detecting weld defects throughout a wide temperature range, from -55 to +350 °C (-67 to +662 °F). This means that inspectors can readily employ TOFD inspections at regular, ambient temperatures, and through the wide operating temperature window without any compromise in the quality of the readings. Whether examining materials under extreme heat or typical environmental conditions, TOFD consistently delivers accurate and high-quality results.
What materials can be tested on?
Can I buy individual probes or just pairs?

TOFD is a pitch-catch technique, using two probes arranged in a pair. One probe acts as the transmitter, and the other as the receiver. These two probes work in tandem to send and receive ultrasonic waves, allowing for accurate time-of-flight measurements and the detection of flaws within the material being inspected.

Although two are needed you can purchase individual probes if you need a replacement.
What temperature is the wedge angle defined at?
Why do you have integrated wedges?

Integrated wedges can be used in TOFD setups for several important reasons such as simplicity, alignment, consistency and compactness.

HotSense TOFD integrates the wedges with the transducer, which requires a kit of parts to cover the most common inspection parameters, but the integrated wedges offer many advantages including increased sensitivity, simplicity and reduction in velocity drift when operating across the wide temperature range. It’s important to choose the right type of integrated wedge for the specific application and material being inspected, get in contact with an Ionix expert to find out what wedge you need: contact@ionix.at

For more information and guidance, see our blog How does temperature affect my angled wedge inspection?  – Ionix Advanced Technologies

If you have any further questions or require technical support, please contact Ionix at support@ionix.at

DOWNLOADS

HotSense™ TOFD Datasheet (PDF)
HotSense™ TOFD Full Inspection Kit (PDF)
Transducer Cables Datasheet (PDF)