1. WP 3: traceable surface temperature measurement with contact sensors Claire Elliott (on behalf of Lucia Rosso, INRiM) nd EMPRESS Workshop (18th Apr 2018)
Thank all partners for their efforts
I will present the main outcomes and new developments from the project
Gamma
Forgiati SRL

2. Talk overview Aim & tasks in EMPRESS (WP3)
Before EMPRESS… Problems with conventional systems
Phosphor thermometry systems
Dynamically compensated surface probe
Industrial implementation
Summary

3. EMPRESS WP2
Aim:
To enhance materials/chemical processing by providing more reliable, traceable surface temperature measurement
… such as forming, joining and welding…

4. EMPRESS WP2
Aim:
To enhance materials/chemical processing by providing more reliable, traceable surface temperature measurement
Tasks:
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C

5. EMPRESS WP2
Aim:
To enhance materials/chemical processing by providing more reliable, traceable surface temperature measurement
Tasks:
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C
- apply phosphor thermometry to commercially available apparatus
- develop a novel remote fibre-optic thermometer
- develop a dynamically compensated surface probe

6. EMPRESS WP2
Aim:
To enhance materials/chemical processing by providing more reliable, traceable surface temperature measurement
Tasks:
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C
- apply phosphor thermometry to commercially available apparatus
- develop a novel remote fibre-optic thermometer
- develop a dynamically compensated surface probe
Demonstrate their use in real industrial conditions

7. Before EMPRESS… Conventional surface temperature measurement
Uncertainty of calibration of surface probe typically greater than 10 °C

8. Before EMPRESS… Conventional surface temperature measurement
Uncertainty of calibration of surface probe typically greater than 10 °C
Cannot be performed in some (e.g. moving) industrial processes

9. Before EMPRESS… Conventional surface temperature measurement
Uncertainty of calibration of surface probe typically greater than 10 °C
Cannot be performed in some (e.g. moving) industrial processes
Affected by measuring different materials to those used in calibration

10. Phosphor Thermometry 𝐼 𝑡 = 𝐼 0 exp −𝑡/𝜏
time
Phosphor-based thermometry involves irradiating a phosphor applied to the surface with light and observing the decay in radiant intensity. The decay time, t , is temperature-dependent parameter and its change with temperature is characteristic of each phosphor t
Phosphor response
Intensity I0
I0/e
Excitation signal
𝐼 𝑡 = 𝐼 0 exp −𝑡/𝜏
Magnesium Fluorogermanate doped with Manganese (Mg4FGeO6:Mn), was selected PC
Phosphor
layer
1x2 Coupler
Filter
Optical
fibers
Photo-
Detector
LD Driver
DAQ module
Fitting a shape gives you tau
Don’t need absolute measurements

11. INRiM system Fluorescence excitation/detection portable unit 300 mm
Portable system
What provides traceability – embedded PRTs

12. INRiM system Fluorescence excitation/detection portable unit
The phosphor Mg4FGeO6:Mn was calibrated by contact on the hot plate surface in the temperature range from 30 oC to 450 oC
Phosphor spots
Reference surface
300 mm
Portable system
What provides traceability – embedded PRTs

13. INRiM system Fluorescence excitation/detection portable unit
The phosphor Mg4FGeO6:Mn was calibrated by contact on the hot plate surface in the temperature range from 30 oC to 450 oC
Phosphor spots
Reference surface
300 mm
Portable system
What provides tracability?

14. INRiM system Fluorescence excitation/detection portable unit
The phosphor Mg4FGeO6:Mn was calibrated by contact on the hot plate surface in the temperature range from 30 oC to 450 oC
Phosphor spots
Reference surface
300 mm
Portable system
What provides traceability – embedded PRTs

15. INRiM system Validation at the Indium melting point
A small spot of the phosphor was placed on a pure-indium inclusion in the surface calibrator block
Indium melt pool
Phosphor spots
Optical fibre

16. INRiM system Validation at the Indium melting point
A small spot of the phosphor was placed on a pure-indium inclusion in the surface calibrator block
Indium melt pool
Phosphor spots
Optical fibre
30 s
Phosphor response during
Indium melting

17. INRiM system Validation at the Indium melting point
A small spot of the phosphor was placed on a pure-indium inclusion in the surface calibrator block
Phosphor temperature agrees to within ±0.3 °C with Indium melting point
Indium melt pool
Phosphor spots
Optical fibre
30 s
Phosphor response during
Indium melting
Repeated melting cycles of Indium

18. NPL system
Modified commercial surface calibrator (Fluke Model 3125) to accommodate different surface materials (Steel & Aluminium)
Extrapolation of thermocouples in the block provides traceability
Thermocouples calibrated to ITS-90 via dry block calibrator
Temperature range: 20 C to 300 C.

19. NPL system Used to investigate KS11 :
Contact Probe Dynamic Test: T = 300 C
Used to investigate KS11 :
Dynamic response of a contact probe
Takes > 5 mins to ‘warm-up’
In error by -25 °C at 300 °C

20. NPL system Used to investigate KS11 :
Contact Probe Dynamic Test: T = 300 C
Used to investigate KS11 :
Dynamic response of a contact probe
Takes > 5 mins to ‘warm-up’
In error by -25 °C at 300 °C
Static response of contact probe
Contact Probe Errors (Static)

21. Phosphor Thermometry
Effect of IR background radiation on phosphor thermometry
NPL system tested as well as INRIM
IR Lamp spectrum
Phosphor emission

22. Phosphor Thermometry
Effect of IR background radiation on phosphor thermometry
Slight radiative warming ~0.5 °C
A 1 kW/m2 IR lamp was used

23. Phosphor Thermometry
Effect of IR background radiation on phosphor thermometry
Slight radiative warming ~0.5 °C
Switching the lamp on/off
didn’t result in a significant
disturbance.
(~ 0,1 °C; lower than the
measurement repeatability)

24. CMI surface probe
CMI developed a dynamically compensated surface probe
Overall calibration uncertainty better than 0.8 °C with a repeatability of 0.5 °C
Cross-validated with INRIM, NPL and DTI’s systems
Traceability for the CMI system?
What is DTI system?
What is new about he CMI system?
How is it better than off the shelf?

25. CMI surface probe Cross-validation against: Embedded thermometers
Aluminium hot plate
Stainless steel hot plate

26. CMI surface probe Cross-validation against: (a) Embedded thermometers
(b) With phosphor-
based systems
Aluminium hot plate
Stainless steel hot plate

27. CMI surface probe Cross-validation against: (a) Embedded thermometers
(b) With phosphor-
based systems
Additional studies have been hampered by damage
Aluminium hot plate
Stainless steel hot plate

28. Industrial trials The new phosphor-based method:
hot-forming of aluminium alloy billets at Gamma Forgiati
heat treatment for welding at BAE Systems

29. Gamma Forgiati
Precise temperature control in pre-heating is needed (± 5 °C).
Phosphor spots
70 mm
Thermocouple
Aluminium
alloy billets
Pre-heating tunnel
furnace

30. Gamma Forgiati
Precise temperature control in pre-heating is needed (± 5 °C).
Validation of the pyrometer
Billet
Radiation shield
MW Pyrometer
Optical fibre
Industrial furnace
The point of this was to validate the pyrometer

31. Gamma Forgiati
Precise temperature control in pre-heating is needed (± 5 °C).
Validation of the pyrometer
Billet
Radiation shield
Optical fibre
Industrial furnace
MW Pyrometer
Industrial furnace
Stationary condition
Result of 3 methods is consistent
Aluminium
alloy billets
Thermocouple
Phosphor
Pyrometer

32. Gamma Forgiati
Precise temperature control in pre-heating is needed (± 5 °C).
Validation of the pyrometer
Billet
Radiation shield
Optical fibre
Industrial furnace
MW Pyrometer
Industrial furnace
Pyrometer
Stationary condition
Transient
Transient Condition
Result of 3 methods is consistent
Aluminium
alloy billets
Thermocouple
Phosphor
Pyrometer

33. Gamma Forgiati
Precise temperature control in pre-heating is needed (± 5 °C).
Validation of the pyrometer
Billet
Radiation shield
Optical fibre
Industrial furnace
MW Pyrometer
Industrial furnace
Pyrometer Tc
Stationary condition
Transient Condition
Result of 3 methods is consistent
Aluminium
alloy billets
Thermocouple
Phosphor
Pyrometer

34. BAE Systems
NPL designed, built, calibrated and tested a bespoke instrument

35. BAE Systems
NPL designed, built, calibrated and tested a bespoke instrument

36. BAE Systems
NPL designed, built, calibrated and tested a bespoke instrument
Calibration: 20 °C to 525 °C (Stainless Steel validation target)
As phosphor gets hotter it reduces in signal.
525 about the max limit

37. BAE Systems
NPL designed, built, calibrated and tested a bespoke instrument
Calibration: 20 °C to 525 °C (Stainless Steel validation target)
Gavin will be discussing later
Minor shift from initial calibration – annealing effect?
For T < 500°C: SD < 0.4 C for 1 s measurement time
UT  2 C

38. BAE Systems
NPL designed, built, calibrated and tested a bespoke instrument
Calibration: 20 °C to 525 °C (Stainless Steel validation target)
Some drift – but never greater than 0.6 C
Gets better with time
Minor shift from initial calibration – annealing effect?
For T < 500°C: SD < 0.4 C for 1 s measurement time
UT  2 C

39. BAE Systems
Calibration laboratory tests – day 1

40. BAE Systems Calibration laboratory tests – day 1
T(phos) > T(contact probe) consistently
Contact probes are variable: saw similar behaviour in NPL tests
They don’t follow each other – contact probes are very variable
Dust oxidation etc.

41. BAE Systems Field trials pre/post welding – day 2
Monitoring pre/post-weld temperatures on section of submarine steel

42. BAE Systems Field trials pre/post welding – day 2
Monitoring pre/post-weld temperatures on section of submarine steel

43. BAE Systems
T(phos) compared to T(contact probe), along with welded type-K thermocouples
Main conclusion for this figure = Phosphor is high – suggests others under-read
First figure: Pre-weld spot reading

44. BAE Systems
T(phos) compared to T(contact probe), along with welded type-K thermocouples
Heat input from welding process monitored in real time and recorded easily
First figure: Pre-weld spot reading
MUST not make another weld before the steel has cooled below the “interpass temperature”

45. Summary
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C
NPL
INRiM
Calibrated & validated

46. Summary
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C
Dynamic response time of T-probe
Effect of IR background radiation

47. Summary
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C
CMI’s surface probe

48. Summary
Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C
Trials at Gamma Forgiati
BAE Systems

49. Thank you Gamma Forgiati SRL
The National Physical Laboratory is operated by NPL Management Ltd, a wholly-owned company of the Department for Business, Energy and Industrial Strategy (BEIS).