WP 3: traceable surface temperature measurement with contact sensors Claire Elliott (on behalf of Lucia Rosso, INRiM) 2nd EMPRESS Workshop (18th Apr 2018) claire.elliott@npl.co.uk Thank all partners for their efforts I will present the main outcomes and new developments from the project Gamma Forgiati SRL

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

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

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

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

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

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

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

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

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

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

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

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?

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

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

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

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

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.

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

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)

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

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

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)

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?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

BAE Systems Calibration laboratory tests – day 1

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.

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

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

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

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”

Summary Develop and validate traceable surface temperature measurement techniques for temperatures below 500 °C NPL 20-300 INRiM 30-450 Calibrated & validated

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

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

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

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).