1、 FORD LABORATORY TEST METHOD CA 006-01 Date Action Revisions Rev. 1 2018 03 29 Editorial See Summary of Revisions K. Redlin, NA 2017 07 07 Released K. Redlin, NA Controlled document at www.MATS Copyright 2018, Ford Global Technologies, LLC Page 1 of 5 ULTRASONIC GAUGE LOSS MEASUREMENT OF ELECTROCOAT
2、ED STEEL TEST PANELS WITH AN UNCOATED AREA ON ONE SIDE Application This procedure is designed to ultrasonically determine gauge loss in a locally uncoated region of Electrocoated (E-coated) steel panels after exposure to either the CETP: 00.00-L-467 or CETP: 00.00-R-343 Ford corrosion procedures. Th
3、e uncoated area must be large enough to take 12 unique measurements with the chosen probe. Apparatus and Materials Required E-coated Cold Rolled Steel Corrosion Panel with Uncoated Region Ultrasonic Thickness Gauge Olympus 38DL Plus with appropriate probe (or equivalent) Plexiglass Acrylic (or Simil
4、ar Material) Measurement Template Glycerin Couplant Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities. Factors affecting performance and accuracy include calibr
5、ation, surface roughness of the test piece, coupling technique, curvature of the test piece, taper or eccentricity, acoustic properties of the test material (sound scattering, sound attenuation or absorption, and velocity variations), and phase reversal or phase distortion. Procedure Before beginnin
6、g the procedure, check the calibration information and date of service for the ultrasonic thickness gauge. Ensure the instrument is in agreement with calibration deadlines. Reference the instruction manual for set-up information specific to the application. 1.0 Determine the E-coat Correction Factor
7、 from an Untested Sample An “E-coat Correction Factor” must be empirically determined to account for the fact that two layers of E-coat are measured during “Reference Area Measurements”, and only one layer of E-coat is measured during the “Corroded Area Measurements”. 1.1 Obtain an untested panel fr
8、om the group of samples being tested (Figure 1a). The group of samples should all share a common coating process. 1.2 Lay the sample on a flat surface with the uncoated region facing down. Apply glycerin couplant to the fully coated side of the panel opposite an area with E-coat present. 1.3 Place a
9、 measurement template (Figure 2) on the sample so the measurement holes are located where glycerin couplant was applied opposite an E-coated area. The template can be taped to the back of the panel to prevent movement if necessary. FORD LABORATORY TEST METHOD CA 006-01 Copyright 2018, Ford Global Te
10、chnologies, LLC Page 2 of 5 1.3.1 The measurement template must have measurement holes sized appropriately for the specific probe being used. The measurement holes must be oriented to allow for measurements in unique locations on the panel. 1.3.2 Ensure glycerin couplant uniformly covers the sample
11、surface in the measurement holes. 1.4 Using the measurement template holes as a guide, take ten (10) thickness measurements from the reference area where E-coat is present on both sides of the panel. Ensure the measurement is stable and repeatable before recording the value. 1.5 Remove the template
12、from the sample and apply glycerin couplant to the fully coated side of the panel opposite the uncoated region. 1.6 Place the measurement template on the sample so the measurement holes are located where glycerin couplant was applied opposite the uncoated region. The template can be taped to the bac
13、k of the panel to prevent movement if necessary. 1.6.1 Ensure glycerin couplant uniformly covers the sample surface in the measurement holes. 1.7 Using the measurement template holes as a guide, take ten (10) thickness measurements from the area opposite the uncoated region. Ensure the measurement i
14、s stable and repeatable before recording the value. 1.8 The absolute difference between the means of the two data sets will serve as the E-coat Correction Factor for that specific group of panels. 2.0 Test Sample Measurements 2.1 Obtain an E-coated steel panel with a locally uncoated region that has
15、 been subjected to either the CETP: 00.00-L-467 or CETP: 00.00-R-343 Ford corrosion procedures. 2.2 Remove any tape or other material from the sample if applicable. 2.2.1 Thick cakes of residual rust can be removed from the sample surface before conducting thickness measurements. Panels can be measu
16、red with slight rust still present by employing an empirically determined Rust Correction Factor (31 um). 2.2.1.1 The Rust Correction Factor should not be used for samples with less than 100 um of gauge loss, (“Uncorrected Difference” 100 um) or if the rust separates from the steel without leaving a
17、ny residual adherent oxide. Samples with gauge loss below the 100 um threshold will contain unknown variability in the correction factor of up to 31 um unless the oxide is removed. 2.3 Lay the sample on a flat surface with the uncoated corroded region facing down. Apply glycerin couplant to the full
18、y coated side of the panel opposite an area with E-coat present. 2.4 Place the measurement template on the sample so the measurement holes are located where glycerin couplant was applied opposite an E-coated area. The template can be taped to the back of the panel to prevent movement if necessary. 2
19、.4.1 Ensure glycerin couplant uniformly covers the sample surface in the measurement holes. 2.5 Using the measurement template as a guide, press the transducer probe to the panel surface. Document the value displayed by the ultrasonic thickness gauge as a “Reference Area Measurement” when the value
20、is stable and repeatable. FORD LABORATORY TEST METHOD CA 006-01 Copyright 2018, Ford Global Technologies, LLC Page 3 of 5 2.5.1 Repeat step 2.5 until six (6) “Reference Area Measurements” have been taken from unique points opposite an E-coated area. Ensure measurement locations are distributed acros
21、s the reference area. 2.6 Remove the template from the sample and apply glycerin couplant to the back side of the panel opposite the uncoated corroded region (Figure 1b). 2.7 Place the measurement template on the sample so the measurement holes are located where the glycerin couplant was applied opp
22、osite the uncoated corroded region. The template can be taped to the back of the panel to prevent movement if necessary. 2.7.1 Ensure glycerin couplant uniformly covers the sample surface in the measurement holes. 2.8 Using the measurement template as a guide, press the transducer probe to the panel
23、 surface. Document the value displayed by the ultrasonic thickness gauge as a “Corroded Area Measurement” when the value is stable and repeatable. 2.8.1 Repeat step 2.8 until twelve (12) “Corroded Area Measurements” have been taken from unique points opposite the uncoated corroded area. Ensure measu
24、rement locations are distributed across the back of the uncoated corroded area. Evaluation A report generated from this test method should include relevant sample identification and all measurement data. A sample data table is shown below in Table 1. Corroded Area Mean: The average of measurements f
25、rom the Corroded Area. Reference Area Mean: The average of measurements from the Reference Area. Uncorrected Difference: The difference between the “Reference Area Mean” and the “Corroded Area Mean”. Rust Correction Factor: The correction constant for surfaces with rust/oxide present during measurem
26、ents. This correction constant should not be used for samples with an “Uncorrected Difference” of less than 100 um or if the rust separates from the steel without leaving residual adherent black oxide. E-coat Correction Factor: The correction constant for the E-coat of a specific group of panels. Co
27、rrected Net Corrosion: Sum of the “Uncorrected Difference”, “E-coat Correction Factor” and “Rust Correction Factor” (if applicable). Table 1: Example data table. Sample Identity Mean (um) S.dev (um)Example 1 1 2 3 4 5 6 Corroded Area: 557 29Reference Area 764 764 764 763 763 763 Reference Area: 764
28、1590 575 542 560 510 572 Uncorrected Difference: 206574 573 502 586 575 530 Rust Correction: 31E-coat Correction: -5Corrected Net Corrosion: 232Corrected Max Sector: 288Sample Identity Mean (um) S.dev (um)Example 2 1 2 3 4 5 6 Corroded Area: 558 27Reference Area 760 760 762 761 759 761 Reference Are
29、a: 761 1560 576 577 566 570 532 Uncorrected Difference: 202573 578 590 540 540 495 Rust Correction: 31E-coat Correction: -5Corrected Net Corrosion: 228Corrected Max Sector: 292Corroded AreaCorroded AreaThickness Measurement (um)Thickness Measurement (um)FORD LABORATORY TEST METHOD CA 006-01 Copyrigh
30、t 2018, Ford Global Technologies, LLC Page 4 of 5 Corrected Max Sector: The maximum value obtained by subtracting individual “Corrosion Area” measurements from the “Reference Area Mean”, and corrected by adding the “E-coat Correction Factor” and “Rust Correction Factor” (if applicable). Summary of R
31、evisions 2018 03 29 - Editorial Updated e-coat callout in the appendix Updated ultrasonic thickness gauge callout in appendix Changed gage spelling to gauge Appendix Potential Supplier Contact Information Ultrasonic Thickness Gauge Olympus 38DL Plus and Couplant B Glycerin: Olympus America Inc. 48 W
32、oerd Ave Waltham, MA, 02453, United States Tel: (800) 225-8330 ordersolympus- http:/www.olympus- Figure 2: Steel panel with an example measurement template. Uncoated Area Corroded Area Figure 1. Example steel panel (a) before corrosion testing with an Uncoated Area, and (b) after corrosion testing w
33、ith a Corroded Area. (a) (b) FORD LABORATORY TEST METHOD CA 006-01 Copyright 2018, Ford Global Technologies, LLC Page 5 of 5 Test Panels: ACT CRS 03x04x032 Alkaline clean, tape per diagram, P: B958P90I E: Aqua EC 4027 Part Number 61934 ACT Test Panels LLC 273 Industrial Drive Hillsdale, MI, 49242 Tel: (517) 439-1485 http:/
