Standard Operating Practice S.O.P. No

Transcription

1 Page 1 of PURPOSE 2.0 SCOPE FLUORESCENT MAGNETIC PARTICLE INSPECTION To establish procedure and control tests for fluorescent magnetic particle inspection. This document establishes minimum requirements for magnetic particle inspection used for detection of surface or slightly subsurface discontinuities in ferromagnetic materials at Eaton. 3.0 APPLICABLE DOCUMENTS ASTM E 1444 ARG R SOP QCP 3.0 QCP 10.0 ARG AMS-3044 AMS-3045 AMS-2641 A.A TAP-PS-931 TAP-PS-932 ENG FC 9283 ARG 2776 ITW Magnaflux "Inspection, Magnetic Particle" Reject Tag Training, Qualification, and Certification of MPI NDT Personnel Document Control Calibration of Measuring and Test Equipment and Standards Nonconformance Report Magnetic Particles, Fluorescent, Wet Method, Dry Powder Magnetic Particles, Fluorescent, Wet Method, Oil Vehicle Vehicle, Magnetic Particle Inspection, Petroleum Base Fluid, Magnetic Particle Inspection, Suspension Cleaning of Parts Cleaning of Parts MPI Acceptance criteria for Discontinuities on Gears, Shafts and Miscellaneous Parts MPI Process Control Log Certificate of Test Liquid Penetrant and Magnetic Particle An explanation of quick break and using the Magnaflux Quick Break Tester Vol. 1 NAS 410 NAS Certification & Qualification of Nondestructive Test Personnel Date of Issue Revision - 3/19/08 AC - 10/29/15 Changes noted with Ø _ Prepared By Approved By Signature on File M. Hotz Signature on File G.A. Lallathin

2 Page 2 of 11 SNT-TC-1A FED-STD-313 SAE-AS-5282 American Society for Nondestructive Testing Material Safety Data, Transportation Data And Disposal Data For Hazardous Materials Furnished To Government Activities Tool Steel Ring For Magnetic Particle Inspection 4.0 GENERAL REQUIREMENTS 4.1 The inspection process shall be in accordance with ASTM E Qualification of Inspection Personnel All personnel performing final magnetic particle inspection shall be qualified and certified in accordance with NAS 410, SNT-TC-1A, and SOP Personnel performing fluorescent magnetic particle inspection shall refrain from wearing eye glasses with Photochromic lenses that darken when exposed to ultraviolet light. Personnel performing the inspection shall allow their eyes to adapt to the dark a minimum of one minute before performing inspection. 4.3 Magnetizing and Demagnetizing Equipment shall be in accordance with ASTM E Magnetic particle testing equipment shall be checked for performance and accuracy at time of purchase, and at intervals prescribed within the Control Tests section of this SOP Calibration shall be required in the event of a suspected malfunction, when electrical maintenance may affect equipment accuracy or as requested by a customer Inspection Tools 4.4 Material Inspectors shall have access to the following items: Magnifying lens, 10X Pen Light 6" scale having graduations of 1/32" Clean cotton swabs Materials used shall be acceptable to the customer and shall comply to the specifications listed below The liquid used as a vehicle for carrying the magnetic particles for the wet process shall be Odorless Inspection Oil, conforming to AMS-2641 or A.A The vehicle shall be non-fluorescent. Magnetic particles employed shall comply with either AMS-3044 or AMS-3045.

3 Page 3 of In the event a customer s material requirements are more stringent than requirements of this procedure, these requirements shall be specifically addressed in a specific part number SOP. 4.5 Magnetic Particle Inspection Standard Operating Procedure (SOP) SOP s shall be written and controlled in accordance with QCP 3.0 Document Control. 4.6 SOP s shall be in accordance with ASTM E 1444 and contain the following: Identification of the parts to which the procedure applies. This shall include the material and alloy of which the parts are fabricated. Identification of test parts used for system performance verification. Areas of the part to be examined (include a sketch if necessary). Directions of magnetization to be used, the order in which they are applied, and any demagnetization procedures to be used between shots. Method of establishing the magnetization (head shot, central conductor, or coil). Directions for positioning the item with respect to the magnetizing equipment. The type of magnetizing current and the equipment to be used. The current level, or the number of ampere-turns, to be used and the duration of its application. Part preparation required before testing. Type of magnetic particle material (dry or wet, visible or fluorescent, etc.) to be used, the method and equipment to be used for its application, and, for the case of wet particles, the particle concentration limits. Type of records and method of marking of parts after inspection. Acceptance requirements, to be used for evaluation indications and disposition of parts after evaluation. Post-inspection demagnetization and cleaning requirements. The procedure identification number and the date it was written. Sequence of magnetic particle inspection as related to manufacturing process operations Deviations from the following procedure and control tests shall be allowed only with the prior approval of the site MPI NDT Level III. 5.0 PROCEDURE: 5.1 Surface Cleanliness The surface of the parts to be inspected shall be free from grease, oil, rust, scale or other matter which might interfere with the proper distribution and concentration or with the intensity, character, or definition of the deposit of magnetic particles. Part cleaning shall be in accordance with TAP-PS-931 and TAP-PS-932. The specific part number SOP shall specify the method of cleaning Masking or plugging of any area of a part shall not be permitted unless the possibility exists that the suspension may damage certain components of the part, (e.g. certain non-metallic parts). Specific instructions will be furnished by the MPI NDT Engineer or the cell Quality Engineer when deemed appropriate.

4 Page 4 of Inspection Sequence Magnetic Particle Inspection (MPI) shall be performed after the completion of operations that could cause surface or near-surface discontinuities, (e.g. forging, heat treating, plating, cold forming, welding, grinding, straightening, machining, and proof loading). MPI shall be performed prior to electroplating being applied. Final MPI shall not be performed with coatings in place that could prevent the detection of surface defects in a ferromagnetic substrate. Such coatings include paint or chrome plate greater than inch. in thickness or electroplated nickel greater than.001 inch in thickness Inspection Methods The wet continuous method shall be initially employed to all MPI parts, as the primary method of particle application. Utilizing this method the magnetic current shall be applied simultaneously with or immediately after diverting the suspension stream from the part The residual magnetizing method may be employed following the continuous method as an interpretation aid Surface Discontinuity Evaluation To distinguish between a surface and a sub-surface discontinuity, the indication shall first be marked at each end using a china marker while holding the part under black light. The indication shall then be wiped away using a solvent dampened swab. The area of the indication shall next be examined using direct white light and 10X magnification for evidence of a surface discontinuity. 5.2 Magnetizing Current Magnitude and Direction The current pulse shall be.6 to.9 second in duration. The suspension shall be applied by hosing or immersion so that all surfaces to be examined are thoroughly covered. Because of the potential of part damage, current pulse in excess of one second shall not be used. Circular magnetization shall precede longitudinal magnetization to assure a measurable demagnetization after the inspection is complete The part shall be magnetized at least twice, once while suspension is being applied and once immediately after application of suspension is stopped Inspection shall consist of at least two separate examinations of each area. The second examination shall be with the lines of magnetic flux approximately perpendicular to those used in the first examination. A different method of magnetizing may be used for the second examination. The above shall apply for all MPI s unless specifically exempted by the MPI NDT Engineer in a written SOP. Adequate magnetic field strengths may be determined by one or a combination of three methods: 1. Testing parts having known or artificial defects of the type, size, and location specified in the acceptance requirements. 2. Using a Hall-effect probe gauss meter capable of measuring the peak values of the tangential field. Tangential-field strengths in the range of 30 to 60 Gauss measured at the part surface are normally adequate magnetization levels for magnetic particle examination when using a Hall effect probe gauss meter. 3. Use of notched shims in accordance with ASTM E 1444 Appendix X2

5 Page 5 of Direct Circular Magnetization Parts shall be circularly magnetized by using 300 to 800 Amps per inch of outside diameter for cylindrically shaped parts. For parts of other shapes, a current of 300 to 800 Amps per diagonal inch of cross-section perpendicular to the direction of the current flow shall be used Separate magnetizing operations shall be used when changes in section are present that differ by more than 30%. In such cases, the sequence of magnetizations shall begin with the lowest current level and proceed in the direction of higher currents. Care shall be taken to avoid damage to smaller sections by overheating. Exception to the 30% change in section requirement shall be allowed only if the higher current level will not saturate the lower current level. This shall be confirmed by use of the pie field strength and direction indicator (segmented indicator), test parts with known defects or a gauss meter Factors which determine the required field strength include the size, shape, and material permeability of the part, the technique of magnetization, the method of particle application and the type and location of defects sought Central Conductor Circular Magnetization A central conductor having as large a diameter as practical, shall be used for circular magnetization of hollow parts. Use 300 to 800 Amps per inch of outside diameter measurement as a base line for the required amperage. Verification of the required amperages shall be performed using a gauss meter or test parts having known defects When hollow parts have I.D.'s substantially larger than the diameter of the central conductor, the distance along the circumference of the part effectively magnetized is considered to be approximately four times the diameter of the central conductor. When the entire circumference is not magnetized at one time, inspect the entire circumference by repositioning the cylinder on the conductor allowing for approximately 10% magnetic field overlap. Use current levels as in para , except diameter shall be considered the sum of the diameter of the central conductor and twice the wall thickness Longitudinal Magnetization Longitudinal magnetization shall be accomplished by encircling the part with a current carrying coil. When using a coil the following conditions shall be met: The part to be inspected shall have length to outside diameter ratio (L/D) between 2 and 15. If L/D ratio is greater than 15, use 15 as maximum regardless of actual value This test shall not be used when L/D is less than The long axis of the part shall be parallel to the axis of the coil opening Part shall be positioned within the coil and as close to the side of the coil as possible without touching the coil wall To insure complete inspection, successive overlapping shots of 10% of parts axis length shall be used when parts axis length exceeds r2 + 3 (width) of coil axis.

6 Page 6 of When using a coil, the current to be used in the inspection should be calculated from one of the following formulas: NI = K L/D (+/- 10%) I = Coil Current in amps K = Constant (45,000) D = Part diameter in inches N = Number of turns in coil L = Part length in inches. Note: Formula for approximate amperage only. For parts with hollow portions, D may be replaced with Deff as given in Formula II. These formulas hold only if L/D is greater than 2 and less than 15. If L/D is less than 2, pole pieces (pieces of ferromagnetic material with the same diameter as the part being tested) shall be placed on each end of the part to effectively increase L/D to 2 or greater. If L/D is greater than 15, the value 15 shall be substituted for L/D. Calculating the L/D ratio for a hollow or cylindrical part. When calculating the L/D ratio for a hollow or cylindrical part, D shall be replaced with an effective diameter, Deff, calculated using: Deff = [(A t - A h ) /π] where A t = the total cross sectional area of the part A h = The cross sectional area of the hollow portions of the part 5.3 ACCEPTANCE CRITERIA The acceptance or rejection of in-house routed parts shall be determined by the specific part number SOP for each part. Specific part number SOP acceptance criteria is derived from Engineering Specification or blueprint (as applicable) Amperage levels for inspection of purchased parts inspected shall be determined by the MPI NDT Level III POST INSPECTION REQUIREMENTS Acceptable Parts Acceptable parts shall be demagnetized, cleaned, ink stamped or chemetched to denote acceptance, and dipped in preservative unless otherwise directed by specific part number SOP. The parts shall be logged and released for further processing. The cleaning process must remove all the magnetic substance after inspection and demagnetization. The approval marking shall be in accordance with the applicable drawing, operational sketch, or as otherwise instructed by the cell Quality Engineer or Eaton MPI NDT Engineer. The marking type, location, and method of application shall be harmless to the part.

7 Page 7 of Rejected Parts Rejected parts shall be tagged with a reject ticket (ARG ) and held for the Quality MPI NDT representative for disposition. (reference par. 8.2). A Non-Conformance Report (ARG-23456) shall be initiated for all rejected parts. If QA review cannot be performed by the end of the rejecting inspectors shift, parts should be de-magnetized, degreased, and have preservative applied. Parts having received QA disposition shall be demagnetized, degreased, and have preservative applied Parts which have been reworked after rejection shall be re-inspected and released for further processing (if applicable) Certification Parts which contain serial numbers shall be listed by serial number on all certifications and/or inspection reports. Parts which have no serial number shall be listed by work order (lot number) and quantity, shall be noted on all certifications and/or inspection reports. 5.4 Demagnetization Holding part in a horizontal plane. Begin about 3 feet in front of the A/C demagnetizing coil; pass the part slowly and steadily through the coil to about 3 feet beyond the end of the coil. Repeat as necessary. Parts significantly smaller in cross section than the coil should be passed through the coil keeping toward the coil wall In addition to demagnetization after inspection, parts must be demagnetized between successive magnetizing operations whenever the residual magnetism from previous magnetizations interferes with the interpretations of indications Following demagnetization, all parts shall be checked for residual magnetism (Ref ) using a certified magnetic field meter. Check parts of complex configuration at all significant changes in geometry. Following demagnetization, a magnetic field meter shall not detect fields with an absolute value greater than 1 gauss anywhere on the part. Unless directed otherwise, all parts shall be demagnetized, cleaned and have a corrosion inhibitor applied after inspection % Residual Magnetism Inspection (following de-magnetization) 1. Verify calibration sticker on magnetic field meter has not expired. 2. Place meter on a non-magnetic bench-top in a horizontal plane. 3. Remove parts from parts basket and inspect each part individually by placing each end of the part as close as possible to the base of indicator without making contact. 3a. Parts having significant changes in geometry should also be checked at the change in geometry. Example: DRIVE SHAFT GEAR IMPELLER SHAFT Check Check Check 4. Acceptable parts shall possess no more than 1 gauss A +1 and -1 = 1 Gauss Total. NOTE: Notify MPI NDT Level III of any problems.

8 Page 8 of CONTROL TESTS Note: Control tests preceded by a encircled letter (Example (A) require that results be entered in the corresponding column of the process control log. 6.1 (A) System performance shall be checked daily by processing a specified test part with known indications. The indications shall reproduce satisfactorily After a major repair, system performance shall be checked by the examination of a certified SAE AS5282 tool steel ring specimen Identification of the ring shall be by electro etching or vibroetching and shall include: Manufacturer s Name, Serial Number, and AS Certification of the ring shall include: Material type, annealing certification, Serial Number, Hardness, Conformance to Fig. 1, SAE AS5282, and Leakage Field Plot The process shall be evaluated by use of the wet continuous method with circular magnetization Amperage shall be as 500 Amps Minimum Number of holes indicated The central conductor shall be a 1 1/8 Dia. Copper Bar not less than 16 long Examination of the ring shall be within 1 minute of current application Parts and rings used for system performance check shall be demagnetized thoroughly cleaned, and checked under black light and preserved as necessary to ensure integrity. 6.2 Suspension (B) Concentration test. The suspension as delivered on the part shall be tested for magnetic substance content by the following method at the start of each shift. The method of test shall be as follows: Run the pump for at least 30 minutes Fill a 100 ml graduated centrifugal tube to the 100-ml mark with suspension directly from the hose or other device used for applying it to the part in an inspection. Demagnetize the suspension and let it stand for l hour to precipitate down Read the volume of the precipitate in the graduate. The volume for fluorescent magnetic particles shall be 0.2 to 0.4 ml. If an adjustment to the suspension is made, repeat steps through

9 Page 9 of Results shall be recorded in the MPI Process Control Log FC (C) Contamination Test This test is similar to the concentration test and shall be performed weekly. The suspension shall be tested for contamination as follows: Perform steps and of paragraph above Examine the liquid above the precipitate with black light. The liquid shall be essentially nonfluorescent Examine the precipitate under both black light and white light. If two distinct layers can be seen, read the volume of each layer. The top layer volume (contamination) shall not exceed 25 percent of the bottom layer volume (magnetic particles). If contamination exceeds 25%, or if the liquid is noticeably fluorescent, the entire suspension shall be discarded and made new. Enter results in the MPI Process Control Log FC (D) Black light shall be checked daily with a Spectroline Accumax XRP-3000 Digital Radiometer, or equivalent. Intensity shall not be less than 1200 microwatts per square centimeter when measured from the face of the light filter to the photocell of the light meter at a working distance of 15 inches. Record results in MPI Process Control Log FC (E) Ambient Light Maximum ambient visible light intensity shall be checked weekly and measure no greater than 2 foot - candles within the darkened fluorescent magnetic particle inspection area. Enter results in Process Control Log. Use Spectroline Accumax XRP-3000 Digital Radiometer, or equivalent. Ø (F) White Light White inspection light shall be checked weekly and measure not less than 125 foot candles at the work surface. Record results in MPI Process Control Log FC Light meters used to measure black and ambient white light intensity shall be recalibrated at six (6) month intervals. The meters shall show by means of a sticker, label, etc., the calibration date and an expiration date in accordance with QCP Ammeter Accuracy The unit ammeter(s) shall be calibrated at least once every three months. The method of calibration shall be in accordance with the ammeter accuracy paragraph of ASTM E Comparative readings shall be taken at a minimum of the three output levels encompassing the usable range of the equipment. The equipment meter reading shall not deviate by more than +/- 10 percent of full scale of the test meter. Results shall be recorded in Instrument Standards' Log Change Suspension (When Bath Fails Contamination Test) As necessary, the Magnetic Particle Liquid Bath containing ferromagnetic particles shall be drained. After draining add two gallons of clean vehicle to the trough and activate circulation pump for two minutes, then drain again Remove, blow clean, and replace the filter screen. Wipe clean the trough area and all work surfaces using clean shop towels dampened with clean vehicle.

10 Page 10 of Thoroughly mix 1/6 oz of unused fluorescent magnetic particles to each gallon of unused liquid vehicle in a clean container. Add 12 to 14 gallons of mixed suspension into the machine trough. Perform suspension and contamination tests per 6.2 and (G) Internal Shorting With the unit set for maximum amperage through the contacts, there shall be no deflection of the ammeter when the current is actuated with no conductor between the contracts, both in the extended and retracted positions. Verify monthly and record results in the MPI Process Control Log FC (H) Quick Break Test for equipment possessing "quick-break" circuitry The "Quick-Break" tester provides a convenient means of checking magnetizing coil circuitry. "Quick-Break" is a term associated with the circuitry employed to rapidly terminate high amperage direct current flowing in a magnetizing coil. The resulting rapid collapse of the coil's magnetic field imparts a very desirable residual field within a part undergoing test. The nature of this field is advantageous for disclosing certain transverse discontinuities on the surface of a part via the residual method (even though the continuous method is being employed) Operation of the "Quick-Break" tester is quite simple and positive. A neon lamp, built into the tester will flash when the magnetizing current decay rate is fast enough to produce the desired "Quick-Break" effect. The quick break tester shall be calibrated annually Operating procedures shall comply with ITW Magnaflux an explanation of quick break and using the Magnaflux quick break tester. Perform test monthly and record results in the MPI Process Control Log FC (I) Coil Current Control The coil current shall be checked weekly by setting the unit for maximum current through the coil. Pulse the electrical current and record the ammeter reading. The product of this current, times the number of turns in the coil (5), shall be at least 15,000 ampere-turns. If the unit delivers less than this amount, the unit shall be placarded with a statement of its maximum rating, maintained within +/- 10% of previous readings, and shall be limited to inspections within the maximum placarded value. Failure to hold the placarded value shall result in the discontinued use of the unit until it has been repaired or replaced (J) Woven Copper Contact Pads Check condition of pads for burns, loose wires, on other detrimental conditions. Turn to a good side or replace as needed. Shall be performed weekly and entered in process control log Current Pulse The Current pulse shall be.6 to.9+/- 0.1 second in duration. This test is to be performed at least once every 3 months. Results shall be recorded in the Instrument Standards' Log. 6.6 Residual Magnetic Field Indicator (Work Area and Master): Work Area - Work area field indicator shall be compared against the "Master" field indicator. The comparison shall be made in a known magnetic field. The readings (either Gauss or Oersteds) (+) and (-) shall be within the pre-established values for this comparison. A check of the work area field indicator shall be made whenever abused, (e.g. dropped or once every 90 days maximum). Results shall be recorded in Instrument Standards' Log.

11 Page 11 of Master - A certified "master" field indicator Magnaflux (P/N , or P/N ) certified FW Bell Model 5070 or equivalent shall be used Whenever the meter fails to pass verification of its accuracy, it shall be removed from the system at once, and either repaired recertified, or replaced. Field indicator calibration history shall be maintained by the Instrument Standard's Lab. 6.7 Deviations from the above requirements shall be corrected before production parts are processed. 7.0 SAFETY 7.1 Personnel performing MPI shall familiarizes themselves with and adhere to the health and safety factors as prescribed by the manufacturers of all materials used in the inspection process. Suppliers' of all MPI materials shall provide Material Safety Data Sheets with all products. These data sheets shall be prepared in accordance with FED-STD PRECAUTIONS TO AVOID HANDLING AND TRANSFER DAMAGE 8.1 Acceptable Parts Parts shall, as a minimum, be re-packaged in a similar fashion as when received, (e.g. bagged, boxed, separators, covers, etc.) so as to preclude their being damaged by handling or in transit. 8.2 Rejected Parts Until these parts receive Eaton s final disposition, they shall all be conspicuously identified per par above. They shall also, as a minimum, be repackaged in a similar fashion as when received so as to preclude any damage. Parts are never be mixed in with acceptable parts and kept segregated. Containers shall be clearly marked as containing rejected material. 9.0 REPAIR STATION AND ENGINEERING HARDWARE 9.1 MPI to be performed on Non-OEM Production parts (e.g., repair station, engineering, etc.) shall be inspected in accordance with the associated part SOP. 9.2 The MPI Level III shall be contacted in the event that a SOP is not available.