1、 FORD LABORATORY TEST METHOD CA 006-01 Date Action Revisions Rev. 0 2017 07 07 Released K. Redlin, NA Controlled document at www.MATS Copyright 2017, Ford Global Technologies, LLC Page 1 of 4 ULTRASONIC GAGE LOSS MEASUREMENT OF ELECTROCOATED STEEL TEST PANELS WITH AN UNCOATED AREA ON ONE SIDE Applic
2、ation This procedure is designed to ultrasonically determine gage 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. The uncoated area must be large enough to take 12 unique measure
3、ments 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 Similar Material) Measurement Template Glycerin Couplant Chemicals,
4、 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 calibration, surface roughness of the test piece, coupling technique
5、, 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 beginning the procedure, check the calibration information and date of
6、 service for the ultrasonic thickness gage. 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 from an Untested Sample An “E-coat Correction Factor” must be
7、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 from the group of samples being tested (Figure 1a). The group of
8、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 measurement template (Figure 2) on the sample so the measureme
9、nt 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 2017, Ford Global Technologies, LLC Page 2 of 4 1.3.1 The measurement template must
10、 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 surface in the measurement holes. 1.4 Using the measurement tem
11、plate 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 from the sample and apply glycerin couplant to the fully coated
12、 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 back of the panel to prevent movement if necessary. 1.6.1 Ensure g
13、lycerin 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 is stable and repeatable before recording the value. 1.8 The abs
14、olute 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 been subjected to either the CETP: 00.00-L-467 or CETP: 00.00-
15、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 measured with slight rust still present by employing an empirically
16、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 gage loss, (“Uncorrected Difference” 100 um) or if the rust separates from the steel without leaving any residual adherent oxide. Samples with gage loss below the 100
17、 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 fully coated side of the panel opposite an area with E-coat present.
18、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. 2.4.1 Ensure glycerin couplant uniformly covers the sample surface
19、 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 gage as a “Reference Area Measurement” when the value is stable and repeatable. FORD LABORATORY TEST METHOD CA 006-01 Co
20、pyright 2017, Ford Global Technologies, LLC Page 3 of 4 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 across the reference area. 2.6 Remove the template from the sample and
21、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 opposite the uncoated corroded region. The template can be taped to t
22、he 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 surface. Document the value displayed by the ultrasonic thickness
23、 gage 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 measurement locations are distributed across the back of the uncoated co
24、rroded 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 from the Corroded Area. Reference Area Mean: The average of measurem
25、ents 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 measurements. This correction constant should not be used for samples with
26、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. Corrected Net Corrosion: Sum of the “Uncorrected Difference”, “E-coat
27、 Correction Factor” and “Rust Correction Factor” (if applicable). 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 applicabl
28、e). 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 1590 575 542 560 510 572 Uncorrected Difference: 206574 573 502 586 575 530 Rust Correction: 31E-coat Correction: -5Corrected Net
29、 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 Area: 761 1560 576 577 566 570 532 Uncorrected Difference: 202573 578 590 540 540 495 Rust Correction: 31E-coat Correction: -5Correc
30、ted Net Corrosion: 228Corrected Max Sector: 292Corroded AreaCorroded AreaThickness Measurement (um)Thickness Measurement (um)FORD LABORATORY TEST METHOD CA 006-01 Copyright 2017, Ford Global Technologies, LLC Page 4 of 4 Appendix Potential Supplier Contact Information Panametrics MX25 Ultrasonic Gag
31、e and Couplant B Glycerin: Olympus America Inc. 48 Woerd Ave Waltham, MA, 02453, United States Tel: (800) 225-8330 ordersolympus- http:/www.olympus- Steel Panels: ACT CRS 03x04x032 Alkaline clean, tape, per diagram B958P90I E: ES21 Part Number 56715. ACT Test Panels LLC 273 Industrial Drive Hillsdale, MI, 49242 Tel: (517) 439-1485 http:/ 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 with a Corroded Area. (a) (b)
