5021-drsciammarella-measurementofpowertransferredtosubstrat

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7/11/2005 Alion Science & Technology 1

Measurement of PowerMeasurement of Power

Transferred to Substrate inTransferred to Substrate inLaser/Arc Cladding and HardfacingLaser/Arc Cladding and Hardfacing

Dr. Valdemar Malin

Dr. F.M. Sciammarella

DuPage Manufacturing Research Center

3850 Ohio Avenue, St. Charles, IL 60174


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PMCSPMCS

Power Measurement Calorimetric System

Developed by - Alion Science & Technology

In cooperation with - (PSNS-IMF)

Funded by - ONR


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Main Objective of PMCS:

Accurate control of

Heat input in laser and arc welding

Penetration

Dilution

Microstructure

Auxiliary Objectives:

Calibrate High Power Direct Diode (HPDD) Laser beam power

Detect and offset beam power degradation

Determine thermal efficiency of HPDDL

Determine thermal efficiency of CO2, Nd:YAG, and Gas Tungsten

Arc


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Who May Need PMCSWho May Need PMCS??

Users of GTAW, PTAW, LBW

Manufacturers of critical components made of:

Heat sensitive steel such as HY-100 to control heat input

(Navy) High Strength Al and Ti alloys to control penetration (NASA,

Aerospace)

Low expansion iron nickel alloys such as INVAR 36 to controldilution (Die repair, auto industry)

Duplex stainless steel to control balanced ferrite-austenite

microstructure (Navy)


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Arc/Laser Beam Power (Definitions)Arc/Laser Beam Power (Definitions)

H = Pnet/ S (J/in)

where S - travel speed (in/s)

where k - thermal efficiency (%)

Heat input H energy absorbed by substrate per unit

of weld length

Input power Pin

(Watts) power delivered to substrate Net power Pnet (Watts) power absorbed by substrate

Pnet = k Pin


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Arc welding :

whereI - amperageV - voltage

Laser beam welding:

Pin is determined by special devices

Pin = I x V

Determination of PDetermination of Pinin


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Pnet is determined by special devices (mostly calorimetric)

Devices are custom made by researchers

Low accuracy and repeatability

Thermal efficiency k is influenced by design of devices and

experimental conditions

Thermal efficiency reported over last 50 years for GTAW:

k = 21-80%

Determination ofDetermination of PPnetnet in Arc and Laser Beam Weldingin Arc and Laser Beam Welding


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Only product on the market for Pnet measurement

Designed for biomedical research but used in weldingapplications recently (Lehigh University, Sandia National Lab)

Output - voltage signal, not net power

Not production oriented (6 hours per measurement)

Does not measure energy lost during processing (about 15sec)

Does not differentiate between transient and quasi-stationary

energiesActual accuracy may reach (7-9%)

Based on the gradient layer temperature principle (notcalorimetry)

Seebeck Envelope CalorimeterSeebeck Envelope Calorimeter


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Complete turnkey device (measures net power in Watts, not in

Volts)

Production oriented device (3min per measurement instead of 6hours)

No transfer of specimen into calorimeter needed

Measures quasi-stationary net power (ignores transient power)

Measurement error < 2% (rather than 7-9%)

Equipped with calibration device

(PMCS)(PMCS) --


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(1)

(6) (4)

(5)

(2)

1- Calorimeter, 2- Auxiliary calorimeters, 3- Water and electrical control,

4- Calibration device, 5 Water supply, 6 - Pendant

PMCS DesignPMCS Design

(3)

PMCS i O tiPMCS i O ti


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PMCS in OperationPMCS in Operation


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Checks accuracy of PMCS without arc or laser beam

3 kW heater provides constant flow of electrical power to

running waterMeasured parameters

Pc Calibration electric input power (measured by watt meter)

Pm Net power (measured by PMCS)

t Time (measured by PMCS)

Calibration efficiency Ac:

Ac = Pm / Pc 100%

Calibration error Ec :

Ec = 100 - Ac (%)

Calibration Device for PMCSCalibration Device for PMCS


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Thousands of measurements to test accuracy andrepeatability

Test run: 60 measurements in 30 seconds (measureddata processed and recorded into excel spreadsheet)

Test series: 5-12 runs (max 15 min between runs)

Testing PMCS with Calibration DeviceTesting PMCS with Calibration Device


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1 0 22 43.2 21.2 930.5 2,897 2,790 96.31

2 9 22.01 43.14 21.13 929.5 2,892 2,777 96.02

3 14 22.06 43.26 21.2 927.5 2,893 2,780 96.09

4 23 22.12 43.37 21.25 926 2,899 2,781 95.93

5 30 22.15 43.63 21.48 923.5 2,902 2,804 96.626 45 22.24 43.72 21.48 928 2,909 2,817 96.84

7 59 22.28 44.01 21.73 919.5 2,919 2,817 96.51

8 67 22.28 44.02 21.74 920.5 2,913 2,829 97.12

9 73 22.31 43.99 21.68 919 2,910 2,816 96.77

10 81 22.3 43.94 21.64 929.5 2,909 2,843 97.7311 87 22.32 44.01 21.69 912.5 2,896 2,797 96.58

12 95 22.34 44.06 21.72 916 2,902 2,814 96.97

AVG 22.20 43.70 21.50 923.50 2,903.42 2,805.42 96.62

STDEV 0.13 0.36 0.24 5.92 8.522 20.852 0.51

Testing PMCS with Calibration DeviceTesting PMCS with Calibration DeviceTable 1 - Test series # 3 (Room temp = 22oC)

Test

run #

Elapsed

Time (min)

Tin

(o

C)

Tout

(o

C)

T

(o

C)

w

(g)

Pc

(W)

Pm

(W)

Ac

(%)

Ec

(%)

3.38


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Random Error AnalysisRandom Error Analysis

Type oferror

Object ofmeasure

Absoluteerror

Relativeerror

Instrument Tin 0.10oC 0.45%

Tout 0.15 oC 0.35%w 0.50 g 0.05%

Pc 0.20%

Total (inst) 1.05%

Calculation T (inst) 0.25 oC

T (60) 0.03

o

C 0.14%time 0.00 sec 0.00%

Total (sys) 0.14%

Random

(total)

1.19%


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Systematic Error AnalysisSystematic Error AnalysisTrend over time (Table 1)Trend over time (Table 1)

Pm

- 66 W (2.4%)

Pc - 28 W (0.9%)

Tin ,Tout ,T ,Pm ,Pc

Pm - Pc = 38 W (1.5%)

43

43.2

43.4

43.6

43.8

44

44.2

Tem

p(oC)

2.85

2.87

2.89

2.91

2.93

2.95

2.97

2.99

Power(kW)

Tout Pc

21

21.2

21.4

21.6

21.8

22

22.2

22.4

22.6

22.8

23

0 20 40 60 80 100Time (min)

Temp(oC)

2.7

2.72

2.74

2.76

2.78

2.8

2.82

2.84

Power(kW)

Tin Pm

Tout

Pc

T

Tin

Pm

Elapsed time (min)Elapsed time (min)

S i E A l i


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Systematic Error AnalysisSystematic Error Analysis

Note: each point indicates avg. value from test series

21

21.2

21.4

21.6

21.8

22

22.2

22.4

22.6

22.8

20 22 24 26 28 30Outside Temperatore To (oC)

Temp(oC)

2.78

2.80

2.82

2.84

2.86

2.88

Power(kW)

Tin Pm

43.2

43.4

43.6

43.8

44.0

44.2

44.4

44.6

44.8

Temp(oC)

2.90

2.92

2.94

2.96

2.98

Power(kW)

Tout Pc

recommendedoperating range

Tout

Tin

T

Pc

Pm

Temperature


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Systematic Error AnalysisSystematic Error Analysis

Effect of outside temperature To on Pm Error caused by deviation of To from recommended 22

oC

Error caused by maximum deviation of To withinrecommended range (22 2 oC)

Relative error caused by maximum deviation of To withinrecommended range (22 2 oC)

Net power (adjusted for environment)

eTo = 8.24 (22 - To) (W)

eTo max = 16W

ETo max

= eTo max

/Pc 100 = 16/2903 = 0.55%

Pnet = Pm + eTo


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Based on preliminary results, the calibrationefficiency varies in the following range:

Ac = 98.2% - 99.2%

The calibration error varies in the following

range:Ec = 1.8% - 0.8%

Summary from error analysisSummary from error analysis


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The most advanced Power Measurement

Calorimetric System (PMCS) for laser and arc

welding has been developed to:

Measure net power directly (in Watts) At high speeds (3 min/measurement)

With minimum error (less than 2%) and Withstand shop environment.

CONCLUSIONSCONCLUSIONS --

5021-drsciammarella-measurementofpowertransferredtosubstrat

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