Study of Thermal Mass Effects on Drying Methods in Preparation for Fluorescent Penetrant Inspection

Transcription

1 Funding provided by the Federal Aviation Administration as Delivery Order IA052 as part of Contract #DTFA D Study of Thermal Mass Effects on Drying Methods in Preparation for Fluorescent Penetrant Inspection Lisa Brasche, Rick Lopez, and Dave Eisenmann Center for NDE, Iowa State University, Ames, IA, USA Keith Griffiths Rolls Royce, plc., Derby, UK

2 Abstract Fluorescent penetrant inspection is widely used to inspect critical rotating components for the presence of surface breaking defects. Typically these components are made of titanium or nickel alloys and can weigh in excess of several hundred pounds. In preparation for FPI, the parts are cleaned to remove contamination and soil from inservice use. The final step in the cleaning process and prior to FPI, is drying. Two methods are commonly used to dry the part, flash dry and oven dry. Prior studies were completed to assess potential differences between the two drying methods in regards to their effectiveness in preparation for FPI and reported at QNDE. However, the earlier studies were limited to coupons and thus, did not take into consideration potential thermal mass effects. The latest study used a 300 pound nickel engine disk which contained fatigue cracks generated during spin pit testing.

3 Objective Evaluate geometry and high thermal mass effects on brightness in response to changes in processing parameters. Utilized real part with fatigue cracks generated during spin pit test and provided for use by Rolls Royce. Weights approx. 300 lbs Waspaloy material Changing geometry High mass to volume ratio Shot peened surface

4 Part Preparation Vapor degrease at 183F for 15 min

5 Drying Methods Oven dry for 30 min at 225 or 250F Flash dry for 15 min ( F) Oven dry temperature measurement Flash dry temperature measurement

6 FPI Processing Level 4, PE Penetrant, 20 min dwell Spray rinse, 60 sec Emulsification with agitation, 120 sec Final spray rinse, 60 sec

7 Developer Application Developer application in dust chamber Pre-developer, oven dry at 160F for 20 min Hand application by tossing of dry powder Removal of excess developer powder

8 Developer Application Wand application at 3 3 distance Wand application at 3 3 distance Dry developer applied with force Bulb application of dry powder developer

9 Brightness Measurement Brightness measurements made with Photo Research PR-880 photometer UVP XX-BLB 17 fluorescent UVA source with 850μW/cm 2 at the part surface Fixtures used to maintain disk position Geared tripod head used to manipulate photometer position Photometer Disk fixture UV light source

10 Baseline Process Vapor degrease 5 183F (This increased to default of 20 mins due to persistent FPI indications). Oven 225F for 30 mins Cool to 104F (forced air cooled using fan) Level 4, PE penetrant (ZL-37), dipped and dwelled for 20 mins Wash 60 seconds Emulsify using ZR-10B with agitation for 120 seconds Wash 60 seconds Pre developer 160F for 20 minutes Dry powder developer, ZP-4B, hand processed 10 minute dwell

11 Temperature Monitoring Temperature gages used to determine variation with part geometry bore flange rim Order of increasing temperature: Inner (bore) crack location Flange Bore Rim Outer (rim) Middle (flange)

12 Repeatability Repeatiability of Measurement Process Brightness - Run 2b - BL y = x R 2 = Brightness - Run 2a - BL Brightness measurements were repeated on the same process run to evaluate repeatability of the measurement process

13 Baseline Brightness Results 1.6 AVERAGE - 225OD 225 OD MAX - 225OD MIN - 225OD 1.2 Mar 04 - R2a - BL - 225OD Mar 04 - R3 - BL - 225OD Brightness 0.8 Mar 04 - R5 - BL - 225OD Mar 04 - R8 - BL - 225OD Mar 04 - R10 - BL - 225OD Mar 04 - R12 - BL 225OD Mar 04 - R15 - BL - 225OD Mar 05 - R2-BL-225ODhand A 2B 3 4 4A 4B 5A 6A 7 8 8B Indication ID 8C 8D 8E 8F 9 9A 9B 10A Mar 05- R4-BL-225ODhand Mar 05 - R7-BL-225ODhand

14 Comparison of 250 to 225 OD OD AVERAGE - 225OD MAX - 225OD MIN - 225OD Brightness 0.8 Mar 04 - R4-250OD Mar 04 - R6-250OD Mar 05 - R5-250OD-hand A 2B 3 4 4A 4B 5A 6A 7 8 8B 8C 8D 8E 8F 9 9A 9B 10A Mar 05 - R6-250OD-hand Indication ID AVERAGE OD More variability found with 250OD than 225OD Average brightness essentially the same for both OD temperatures

15 Results of Flash Dry Comparison Flash Dry AVERAGE - 225OD 1.6 MAX - 225OD 1.2 MIN - 225OD Brightness 0.8 Mar 04 - R7-160FD Mar 04 - R9-160FD Mar 05 - R8-183FD-hand A 2B 3 4 4A 4B 5A 6A 7 8 8B Indication ID 8C 8D 8E 8F 9 9A 9B 10A AVERAGE - FD (Mar 04 & Mar 05) AVERAGE - Mar 04 FD Similar average brightness between FD and OD in Mar 04 More variability and lower average brightness found with FD in Mar 05 than 225OD, possibly due to emulsifier effects

16 FD to OD Comparison Average brightness of 250 OD very similar to 225 OD (slope = 0.99) Average brightness of FD somewhat lower than OD when considering Mar 05 data (slope = 0.88) Average brightness of FD very similar to 225OD when consider only Mar 04 data (slope = 0.96) Difference between Mar 04 and Mar 05 could be related to emulsifier contamination Statistical significance being assessed FD Brightness 250 OD Brightness y = x y = x Flash Dry - Baseline Runs Mar 04 - R7-160FD Mar 04 - R9-160FD Mar 05 - R8-183FDhand Linear (AVERAGE - FD (Mar 04 & Mar 05)) Linear (AVERAGE - Mar 04 FD) Average Brightness - 225OD 250 OD y = x Mar 04 - R4-250OD Mar 04 - R6-250OD Mar 05 - R5-250OD-hand Mar 05 - R6-250OD-hand Linear (AVERAGE OD) Average Brightness - 225OD

17 Developer Application - Wand 1.6 Wand Application - 3" distance AVERAGE - 225OD 1.2 MAX - 225OD Brightness 0.8 MIN - 225OD A 2B 3 4 4A 4B 5A 6A 7 8 8B 8C 8D 8E 8F 9 9A 9B 10A Mar 05 - R9-225OD- 3"wand Indication ID Use of wand at 3 distance from part led to lower brightness than hand processing with brightness of 30% of the average brightness found with hand-processing

18 Developer Application - Bulb Comparison of developer application using a bulb led to lower brightness than most hand processed indications Linear regression shows brightness values of 69% for the bulb processing compared to hand processing Brightness Brightness - Bulb Application OD A 2B 3 4 Bulb Application of Developer 4A 4B 5new 5A 6new 6A Indication ID 7 8 Mar 05 - R5-250OD-hand Mar 05 - R6-250OD-bulb 8Anew 8B 8C 8D 8E 8F Developer Application - Bulb vs. Hand y = x 9 9A 9B 10new 10A Brightness - Hand Processed OD

19 New Emulsifier 1.6 Wand Application - 3" distance AVERAGE - 225OD MAX - 225OD MIN - 225OD 1.2 Mar 05 - R9-2 min emul - 225OD-3"wand Brightness A 2B 3 4 4A 4B 5A 6A 7 8 8B Indication ID 8C 8D 8E 8F 9 9A 9B 10A Mar 05 - New Eml-R10-1min emul-250od-3"wand Mar 05 - New Eml-R11-225OD-1min emul-3"in wand Mar 05 - New Emul-R12-225OD-2min emuls+3"wand Mar 05 - New Emulf-R14-225OD-1min-3"wand Mar 05- Average-New Emul-3" wand Brightness increased with new emulsifier compared to original emulsifier Use of wand in general led to a reduction in brightness but less variability than with hand processing

20 Brightness Mar 04 - R2a - BL - 225OD Mar 04 - R2b - BL - 225OD Mar 04 - R3 - BL - 225OD Mar 04 - R4-250OD Mar 04 - R5 - BL - 225OD Mar 04 - R6-250OD Mar 04 - R7-160FD Mar 04 - R8 - BL - 225OD Mar 04 - R9-160FD Mar 04 - R10 - BL - 225OD Mar 04 - R11 - AqW-173FD Mar 04 - R12 - BL 225OD Mar 04 - R13 - AqW-250OD Mar 04 - R14- AqW 173FD - Dev Chb Mar 04 - R15 - BL - 225OD Brightness (Background) Average Brightness Average Brightness Average Corrected Brightness Average Background Background brightness consistent in Mar 04 until R11 R11 involved aqueous wash which decreased the background from that point forward

21 Average Brightness Average Brightness Brightness Mar 05 - R1-BL-225OD-hand Mar 05 - R2-BL-225OD-hand Mar 05- R4-225OD-hand Mar 05 - R5-250OD-hand Mar 05 - R6-250OD-bulb Mar 05 - R6-250OD-hand Mar 05 - R7-225BL-hand Mar 05 - R8-183FD-hand Mar 05 - R9-225OD-DevC Mar 05 - R9-225OD-3"wand Mar 05 - New Eml-R10-250OD- 3"wand Mar 05 - New Eml-R10-250OD-Hand Mar 05 - New Eml-R11-225OD-1min emul-3"in wand Mar 05 -New Eml-R11-225OD+force Mar 05 - New Emul-R12-225OD-2min emuls+3"wand Mar 05 - New Emul-R12-225OD-2min emul+force Mar 05 - New Emulf-R13-183FD-3" wand Mar 05 - New Emulf-R14-225OD- 1min-3"wand Mar 05 - New Emulf - R15-183FD - 3" wand - Alka Wash Brightness (Background) Average Brightness Average Corrected Brightness Average Background Background brightness consistent in Mar 05 even though a change in emulsifier occurred between R9 and R10

22 Flash Dry Comparison 1.6 Wand Application - 3" distance AVERAGE - 225OD MAX - 225OD 1.2 Brightness 0.8 MIN - 225OD Mar 05 - R9-225OD- 3"wand Mar 05 - New Emulf - R15-183FD - 3" wand - Alka Wash A 2B 3 4 4A 4B 5A 6A 7 8 8B Indication ID 8C 8D 8E 8F 9 9A 9B 10A Mar 05 - New Emulf-R13-183FD-3" wand No difference between OD and FD with new emulsifier and 3 wand Brightness increased after heavy duty alkaline clean and FD back to hand processing conditions

23 New Emulsifier New Emulsifier - Brightness Emulsifier Comparison - 3" Wand y = x y = x y = x Mar 05 - New Eml- R10-1min emul- 250OD-3"wand Mar 05 - New Eml- R11-225OD-1min emul-3"in wand Mar 05 - New Emul- R12-225OD-2min emuls+3"wand Mar 05 - New Emulf-R14-225OD- 1min-3"wand Mar 05- Average- New Emul-3" wand R9 - orginal emulsifier - 3" wand Original Emulsifier - Brightness - R9-3" wand Linear (AVERAGE - 225OD) Linear (Mar 05- Average-New Emul- New emulsifier gave better performance than the original emulsifier (slope = 1.28 for new emulsifier compared to 1.0 for original emulsifier) Hand processing had higher average brightness than wand

24 Conclusions Average brightness similar for both oven dry temperatures, i.e., 225F and 250F FD data requires additional statistical analysis More variation found with FD when compared to 225OD, original emulsifier With new emulsifier, FD and OD performed similarly Background brightness relatively consistent in Mar05, i.e., not related to changes in emulsifier Use of wand showed less variability than hand processing but at a lower average brightness Emulsifier change led to improvements in brightness Dust chamber application shows similar brightness debits to those found using lcf samples Use of heavy duty alkaline clean led to improvements in brightness Recommend final study to establish minimum acceptable drying temperature for parts, i.e., energy savings benefits