High Temperature Testing

To assist plant operators in maximizing the availability of their assets and to reduce their shutdown time, Sonotech has developed an online inspection strategy at plant operating temperature.

For in-service inspections when the plant is in full operation, Sonotech has developed a set of “standard” procedures to be able to do corrosion mapping and weld inspections up to 350 deg C. The result is that we can deploy the technique fast, reliable and at reasonable costs.

For inspections from 350 deg C up to 475 deg C or special configurations or special materials, we can develop and validate a specific procedure. A validation block is needed, which will be heated up in the test phase during the preparation. The validation block will be prepared with artificial defects so that it is representative for the client demands. During the preparation phase we will prove what can be reliable detected and sized.

For pre-service inspections on heavy wall vessels or on the so called “golden” welds, we have the possibility to inspect the partially filled weld at pre-heat temperature.

Available techniques are: TOFD, Phased Array, Seescan corrosion mapping, UT wall thickness point measurements, EMAT point measurements and Pulsed Eddy Current corrosion monitoring.

High temperature parameters



Phased Array

Corrosion Mapping

Thickness Measurement


Defect Detection

Defect Monitoring

Corrosion Assessment

Spot Checking

Temperature limitation

485 degrees C

400 degrees C

350 degrees C

500 degress C


Using our high temperature NDT inspection services you get:

– Reduced down time of the plant, by improved maintenance planning / RBI input.
– Reduced shutdown time.
– Monitoring of cracking and corrosion spots during production.
– Inspection of on-line repaired areas, in accordance with ASME code case.
– Wall thickness mapping of the area, before making hottaps.
– Accurate corrosion monitoring up to 500 degrees C, on critical positions, to be able to deviate form the crude menu.
– Significant reduced risk on welds repairs during the construction phase of heavy wall vessels or “golden” welds.

Areas for application:

– Non-intrusive inspections.
– Inspection of partially filled welds during the construction process at the preheat temperature.
– Weld inspection.
– Weld root corrosion monitoring.
– Defect detection.
– Defect monitoring
– Corrosion assessment with Seescan® corrosion mapping.
– Thickness testing with spot checking.
– Corrosion screening and monitoring under insulation with pulsed eddy current.


Our in-house-developed software suite called ScanPlan® aids in the professional preparation of TOFD inspections and minimizes the preparation time required. It is an integrated software package that can either work standalone or in combination with a database. The relevant data consist of the client, site and component information, and of course the TOFD inspection data. It not only helps to find the optimum calibrations and configuration for the TOFD inspection, it also has excellent reporting features. ScanPlan® works in accordance with industry standards such as the Pressure Equipment Directive (PED), American Society of Mechanical Engineering (ASME) and the British Defense Standards (Def Stan).

Scroll to Top