High Temperature NDT Inspection Services
High Temperature NDT Inspection Overview
To assist plant operators in maximising the availability of their assets and to reduce their shutdown time, TÜV Rheinland Sonovation has developed an online inspection strategy at plant operating temperature.
For in-service inspections when the plant is in full operation, TÜV Rheinland 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.
Benefits of Our High Temperature NDT Inspection Services at a Glance
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 deg C, on critical positions, to be able to deviate from the crude menu.
- Significant reduced risk on weld repairs during the construction phase of heavy wall vessels or “golden” welds.
High Temperature NDT Inspection Approach
For regular inspection demands up to 350 deg C, testing on a range of samples has been performed and based on this, a set of “standard” procedures has been drafted. The result is that we can deploy the service fast and reliable all over the world at reasonable costs.
All TÜV Rheinland Sonovation operators are trained in the field of high temperature inspections.
For inspections above 350 deg C and inspections at elevated temperature on complex geometries, we make appropriate and detailed ScanPlans®. During the testing and validation the highest attention is required for this detailed preparation process to determine the necessary set-ups. In the case of TOFD and PA inspections, we pay special attention to calculating wedge angles, which are significantly affected by velocity changes in the material caused by high temperatures. Proce Centre separation (TOFD) and relevant ultrasonic characteristics, such as transducer diameter and frequency must also be taken into consideration.
Emphasis is placed during the pre-site validation work on comparable materials. Typically, tests are carried out on a test specimen at incremental steps of 10°C either side of the required inspection temperature in order to ensure optimum ultrasonic performance. Continuous monitoring of couplant performance is carried out, with the primary challenge remaining the maintenance of efficient coupling with the material. To this end, an adequate couplant medium is required which offers the appropriate viscosity at the required inspection temperature. Another challenge is maintaining the probes and probe shoes under a full technical specification. Special precautions, such as probe cooling, are also taken into account.
High Temperature NDT Inspection Application Range
Our high temperature NDT inspection can be used for:
- Non intrusive inspections
- Inspection of partially filled welds during the construction process at the preheat temperature
- Flaw detection
- Defect monitoring, ie. crack growth monitoring
- Corrosion assessment
- Thickness testing with spot checking.
- Corrosion monitoring with PEC