Materials Compensation Technique for Remote Field Technology users

Ed Brain

Marketing Manager

Russell NDE Systems Inc.

www.russelltech.com1

Agenda

• Background

• RFT defect sizing

• Material compensation in RFT inspection

• Software program description

• Experimental verification of material compensation

• Summary2

Background

• Calibration tubes are required in RFT inspection of carbon steel tubes.

• Calibration tubes are not always identical to the tubes to be inspected. Differences include wall thickness, electric and magnetic properties.

3

Background (continued)

• Even tubes within one bundle are different from each other in wall thickness and material properties.

• It is not practical to prepare a series of calibration tubes that match those in the bundle.

4

Background (continued)

• It is inconvenient to change operating frequency when testing a large tube bundle.

Material compensation (Mat’l Comp) is proposed to take into account differences in both tube wall thickness and material properties before defects are sized.

5

RFT defect sizing

RFT defect sizing can be done through voltage plane polar plot (VPPP) or XY plot.

6

RFT defect sizing (continued)

Typical calibration curves using RFT VPPP and XY plot.

7

Material compensation in RFT inspection

• Material compensation involves calibration defect trace rotation and phase spread adjustment according to RFT theory.

• The amount of trace rotation and phase spread is determined primarily by the difference of nominal phase reading between the calibration and actual samples.

8

Material compensation in RFT inspection (continued)

• Free air phase reading is also needed for material compensation, which is a one-time measurement before tube bundle inspection.

9

Software program description

A screen capture of main window from EasyLog data acquisition and analysis software program.

10

Experimental verificationof material compensation

Short flat defects

• Cal tubef0.75" x 0.083", SA-179

30% and 60% deep flats

• Test tube

f0.75" x 0.085", SA-214

25%, 50% and 75% deep flats 11

Experimental verificationof material compensation (continued)

Short flat defects• Before Mat’l Comp is applied

25% 6%50% 35%75% 61%

• After Mat’l Comp is applied25% 25%50% 52%75% 75% 12

Experimental verificationof material compensation (continued)

Short flat defects

Strip chart and XY plot of three flat defects in a test tube before and after material compensation is applied.

13

Experimental verificationof material compensation (continued)

Short full circumferential grooves

• Cal tube

f0.75" x 0.087", SA-214

20% and 40% deep

• Test tube

f0.75" x 0.109", SA-214

20% and 40% deep14

Experimental verificationof material compensation (continued)

Short full circumferential grooves

• Before Mat’l Comp is applied20% can not be sized

40% 35%

• After Mat’l Comp is applied20% 9%

40% 47%15

Experimental verificationof material compensation (continued)

Flat bottom holes

• Cal tube

f0.75" x 0.087", SA-214

53%, 75% and 100% deep

• Test tube

f0.75" x 0.115", SA-214

50%, 75% and 100% deep16

Experimental verificationof material compensation (continued)

Flat bottom holes• Before Mat’l Comp is applied

50% 60%75% 78%100% 96%

• Mat’l Comp is not applied

Mat’l Comp is not needed since the difference in wall thickness happens to be self-compensated by material property difference.

17

Summary

• Mat’l Comp has been verified through several types of defects in test tubes with differences in wall thickness and/or material properties.

• Mat’l Comp has been implemented in EasyLog software program with capabilities of both data acquisition and analysis.

18

References and Useful Links

• Mackintosh, D.D., D.L. Atherton and S. P. Sullivan, Materials Evaluation, Vol. 51, No. 3, April, 1993, pp.492-495.

• www.physics.queensu.ca/~amg/remote_field.html

19

Ed BrainMarketing Manager

Russell NDE Systems Inc.www.russelltech.com

Questions?

20

Ed BrainMarketing Manager

Russell NDE Systems Inc.www.russelltech.com

Thank You!

21