SAE AMS2304A-2006

SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright © 2006 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: custsvc@sae.org SAE WEB ADDRESS: http://www.sae.org Steel Cleanliness, Special Aircraft-Quality Magnetic Particle Inspection Procedure 1. SCOPE: 1.1 Purpose: This specification covers steel cleanliness requirements in inch/pound units for special aircraft- quality ferromagnetic steels, other than hardenable corrosion resistant steels, by magnetic particle inspection methods. 1.1.1 MAM 2304 is the metric version of this AMS. 1.2 Application: This procedure has been used typically for the cleanliness evaluation of blooms, billets, tube rounds, stock for forging or flash welded rings, slabs, bars, sheet, plate, tubing, and extrusions used in fabricating highly stressed parts where very strict magnetic particle inspection standards are used in final inspection of such parts, but may be used for qualification of a heat, melt or lot of steel. 1.2.1 Product qualified to this specification is not recommended for use in parts where the high transverse properties of vacuum-arc-remelted or electroslag remelted steel are required (See 8.2). 2. APPLICABLE DOCUMENTS: The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been canceled and no superseding document has been specified, the last published issue of that document shall apply. AEROSPACE MATERIAL SPECIFICATION AMS 2304A Issued JAN 1991 Revised JUN 2001 Reaffirmed MAR 2006 Superseding AMS 2304 Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS - - ` , , ` ` ` , , , , ` ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - AMS 2304A SAE AMS 2304A - 2 - 2.1 ASTM Publications: Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. ASTM E 10 Brinell Hardness of Metallic Materials ASTM E 1444 Magnetic Particle Examination 2.2 ANSI Publications: Available from American National Standards Institute, Inc., 11 West 42nd Street, New York, NY 10036-8002. ANSI B46.1 Surface Texture 3. TECHNICAL REQUIREMENTS: 3.1 Specimen Preparation: 3.1.1 Heat Qualification: Sampling shall be in accordance with 4.3.1. Samples shall be converted into test specimens in accordance with 3.1.3. 3.1.2 Product Qualification: Product from a heat not qualified based on sampling as in 4.3.1 shall be sampled in accordance with 4.3.2. Samples shall be converted into test specimens in accordance with 3.1.3. 3.1.3 Working and Rough Machining: 3.1.3.1 Solid Product 12 Inches and Over in Nominal Diameter or Distance Between Parallel Sides: A quarter section shall be cut from the sample sufficiently oversize that the center of the original sample will be approximately on the surface of the specimen after generating to test size. The quartered section shall then be forged to a 3 to 6 inch round or square, maintaining the axis of the forging approximately parallel to the original direction of rolling. As an alternate method, the full section may be rolled or forged to a 6-inch round or square and an oversize quarter obtained as in 3.1.3.3. Specimens shall be rough machined to a “one-step” straight cylinder nominally 5 inches long. Minimum stock removal shall be consistent with the machining allowance specified in 3.1.4.1. 3.1.3.2 Solid Product Over 6 to 12 Inches, Exclusive, in Nominal Diameter or Distance Between Parallel Sides Except Slabs and Plates: A quarter section shall be cut from each sample sufficiently oversize that the center of the original sample will be approximately on the surface of the specimen after generating to test size. The quarter section shall be converted into a test specimen by machining, or forging and machining, to a 3 to 6 inch round or square. Specimens shall be rough machined to a “one-step” straight cylinder nominally 5 inches long. Minimum stock removal shall be consistent with the machining allowance specified in 3.1.4.1. Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS - - ` , , ` ` ` , , , , ` ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - AMS 2304A SAE AMS 2304A - 3 - 3.1.3.3 Solid Product 6 Inches and Under in Nominal Diameter or Distance or Distance Between Parallel Sides Except Flat Bars, Slabs, and Plates: A quarter section shall be cut from each sample sufficiently oversize that the center of the original sample will be approximately on the surface of the specimen after generating to test size. The quarter section shall be converted into a test specimen by machining to a “one-step” straight cylinder nominally 5 inches long. Minimum stock removal shall be consistent with the machining allowance specified in 3.1.4.1. 3.1.3.3.1 As an alternate method, a stepdown specimen may be generated from the full cross-section in equal length circumferential steps as shown in Table 1. 3.1.3.4 Flat Bars: Specimens nominally 5 inches long shall be rough machined to equal-length steps across the width of the specimen, in accordance with Table 2, allowing 20% of the thickness or 0.100 inch, whichever is less, for minimum stock removal. Allowance of 0.010 inch shall be made for finish machining. TABLE 1 - Stepdown Specimens - Cylindrical Nominal Diameter or Distance Between Parallel Sides Inches Step Length Inches Step Diameter 1 Step Diameter 2 Step Diameter 3 Step Diameter 4 Step Diameter 5 0.250 to 0.500, incl 5.000 D -- -- -- -- Over 0.500 to 0.750, incl 2.500 D 2/3D -- -- -- Over 0.750 to 1.000, incl 1.665 D 3/4D 1/2D -- -- Over 1.000 to 1.500, incl 1.250 D 4/5D 3/5D 2/5D -- Over 1.500 1.000 D 4/5D 3/5D 2/5D 1/5D D = Original diameter or distance between parallel sides minus machining stock removed. TABLE 2 - Stepdown Specimens - Flat Bars Nominal Thickness Inch Step Length Inches Step Thickness 1 Step Thickness 2 Step Thickness 3 Step Thickness 4 Step Thickness 5 Up to 0.250, incl 5.000 T -- -- -- -- Over 0.250 to 0.500, incl 2.500 T 2/3T -- -- -- Over 0.500 to 1.000, incl 1.250 T 3/4T 1/2T 1/4T -- Over 1.000 1.000 T 4/5T 3/5T 2/5T 1/5T T = Original nominal thickness minus machining stock removed. Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS - - ` , , ` ` ` , , , , ` ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - AMS 2304A SAE AMS 2304A - 4 - 3.1.3.5 Slabs or Plates: A straight cylindrical or rectangular specimen shall be machined, or forged and machined, from each slab or plate tested. The specimen shall be taken essentially parallel to the direction of rolling at the center of the slab or plate width and thickness and shall be nominally 5 inches in length, and not more than 4 inches in final diameter or thickness. 3.1.3.5.1 Product Up to 4 Inches, Inclusive, in Nominal Thickness: A straight cylindrical specimen shall represent the full thickness consistent with the machining allowance specified in 3.1.4.1. 3.1.3.5.2 Product Over 4 to 8 Inches, Inclusive, in Nominal Thickness: A straight cylindrical specimen shall represent surface to mid-thickness consistent with the machining allowance specified in 3.1.4.1. 3.1.3.5.3 Product Over 8 Inches in Nominal Thickness: A straight cylindrical specimen shall be taken so that the axis is approximately midway between the surface and mid-thickness, and shall have a diameter equal to one-third the nominal thickness of the section. 3.1.3.6 Tubing: 3.1.3.6.1 Nominal Wall Thickness 0.250 Inch and Over: Specimens, nominally 5 inches long, shall be rough machined to 4 equal circumferential steps, T, 3/4T, 1/2T, and 1/4T, allowing 0.100 inch on the diameter for stock removal. Allowance of 0.010 inch on the radii for finish machining shall be made. T = nominal wall thickness minus the machining allowance. 3.1.3.6.2 Nominal Wall Thickness Under 0.250 Inch: Specimens, nominally 5 inches long, after heat treatment as in 3.1.5, shall have 10% of the wall thickness or 0.015 inch, whichever is less, removed from the outer diameter and be tested as a straight cylinder. 3.1.4 Machining: 3.1.4.1 Product Other Than Flat Bars, Slabs, and Plates Over 8 Inches Thick, and Tubing: The converted sample shall be machined to conform to the allowance of Table 3 for surface removal, allowing 0.010 inch per side for finish machining after heat treatment. Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS --`,,```,,,,````-`-`,,`,,`,`,,`--- AMS 2304A SAE AMS 2304A - 5 - 3.1.5 Heat Treatment: Rough machined specimens shall, if necessary, be heat treated by suitably austenitizing, quenching, and tempering or by solution and precipitation heat treating to produce hardness of 248 to 352 HB or appropriate lower hardness for steel of low hardenability. Hardness testing shall be in accordance with ASTM E10. Specimens shall be austenitized in a neutral or slightly reducing atmosphere. Following heat treatment, surface scale may be removed by grit blasting or other acceptable method. 3.1.6 Finish Machining: The heat treated specimens shall be finish machined to surface roughness not greater than 32 microinches AA, determined in accordance with ANSI B46.1. The ends of the specimen shall be finished to provide good electrical contact. 3.2 Inspection: Magnetic particle inspection shall be performed in accordance with ASTM E 1444 by the circular, wet, continuous method (See 8.5) using 800 to 1200 amperes per inch of diameter. If a stepdown bar is used, the smallest step shall be magnetized and inspected first; the larger steps shall be magnetized and inspected individually in succession of increasing size until all steps have been evaluated. If a longitudinal slice from slab or plate, as in 3.1.3.5, is used, only the longitudinal surfaces perpendicular to the two faces of the slab or plate shall be inspected. 3.2.1 Cleanliness standards presented herein govern nonmetallic inclusions only (See 8.5). Steel which, during inspection, reveals indications representing actual ruptures, such as cracks, seams, laminations, and laps, will be subject to rejection except where these defects result from sample preparation. TABLE 3 - Stock Removal Nominal Diameter or Distance Between Parallel Sides Inches Minimum Stock Removal Inch per Side 0.250 to 0.500, incl 0.030 Over 0.500 to 0.750, incl 0.045 Over 0.750 to 1.000, incl 0.060 Over 1.000 to 1.500, incl 0.075 Over 1.500 to 2.000, incl 0.090 Over 2.000 to 2.500, incl 0.125 Over 2.500 to 3.500, incl 0.156 Over 3.500 to 4.500, incl 0.187 Over 4.500 to 6.000, incl 0.250 Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS - - ` , , ` ` ` , , , , ` ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - AMS 2304A SAE AMS 2304A - 6 - 3.2.2 The results of the magnetic particle inspection shall be appropriately recorded. All recorded results shall be identified, filed, and made available to purchaser upon request. 3.3 Evaluation of Steel Cleanliness: After inspection, each indication 1/64 inch and over shall be recorded on an inspection chart. All recorded results shall be identified, filled, and, upon request, made available to purchaser. Records shall be available for at least three years after shipment of the product. The frequency (F) number and the severity (S) length of the indications shall be calculated as follows: 3.3.1 Frequency (F): 3.3.1.1 The number of indications per test specimen is totaled. 3.3.1.2 The frequency per specimen is determined by dividing the total number of indications for each specimen by the test surface area of the specimen frequency in square inches. 3.3.1.3 The frequency ratings for all test specimens from a heat are totaled. 3.3.1.4 The average frequency rating (F) equals the total frequency rating for all test specimens from a heat divided by the number of test specimens. 3.3.2 Severity (S): 3.3.2.1 The length of each indication is recorded. 3.3.2.2 The product for each specimen is computed by totaling the product of the number of indications times the appropriate progression factor shown in Table 4. 3.3.2.3 The severity rating per specimen is determined by dividing the product for each specimen by the test surface area of the specimen in square inches. 3.3.2.4 The severity ratings for all test specimens from a heat are totaled. TABLE 4 - Progression Factor for Severity Rating Length of Indication Inch Progression Factor 1/64 to 1/32,excl 2 1/32 to 1/16,excl 4 1/16 to 1/8, excl 16 1/8 and over 256 Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS - - ` , , ` ` ` , , , , ` ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - AMS 2304A SAE AMS 2304A - 7 - 3.3.2.5 The average severity (S) equals the total severity rating for all test specimens from a heat divided by the number of test specimens. 3.4 Disposition: Product inspected in accordance with this specification shall conform to the following requirements: 3.4.1 Product inspected for heat qualification as in 4.3.1 and for product qualification as in 4.3.2 shall conform to a maximum average frequency rating (F) of 0.25 and a maximum average severity rating (S) of 0.50. 3.4.2 Product inspected in accordance with this specification and having frequency-severity rating exceeding the specified limits may be reevaluated for specific applications when permitted by purchaser. Evaluation of any one or two steps of stepdown specimens may be waived by purchaser when the area represented is not considered critical for the end product. 4. QUALITY ASSURANCE PROVISIONS: 4.1 Responsibility for Inspection: The vendor of the product shall supply all samples for vendor's tests and shall be responsible for the performance of all required tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to specified requirements. 4.2 Classification of Tests: All applicable technical requirements are acceptance tests and shall be performed as specified in 4.2.1 or 4.2.2. 4.2.1 Heat Qualification: Tests of samples taken as in 4.3.1 to determine conformance to heat qualification requirements, if acceptable, need be conducted only once per heat. 4.2.1.1 Heats which have been qualified as semi-finished product shall be considered qualified for finished product. 4.2.2 Product Qualification: Tests on product not "heat qualified" shall be conducted on product of each size and shape of each lot made from each heat. 4.3 Sampling and Testing: The sampling procedure for heat qualification described in 4.3.1 shall be performed by the producer. No further sampling by the producer shall be required from a heat which meets the requirements of 3.4.1. Sampling procedure on the product shall be as described in 4.3.2. Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS --`,,```,,,,````-`-`,,`,,`,`,,`--- AMS 2304A SAE AMS 2304A - 8 - 4.3.1 Heat Qualification: 4.3.1.1 Heats of Top-Poured Ingots: Samples shall be taken from semi-finished or finished product representing the top and bottom of the first ingot and last usable ingot from heats having not more than 10 ingots, or not over 60,000 pounds, or from portions of heats within these limits; and from the top and bottom of the first, middle, and last usable ingot of heats having more than 10 ingots or over 60,000 pounds. 4.3.1.2 Heats of Bottom-Poured Ingots: Samples shall be taken from semi-finished or finished product representing the top and bottom of three ingots. One ingot shall be taken at random from the first usable plate poured, one ingot at random from the usable plate poured nearest to the middle of the heat, and one ingot at random from the last usable plate poured. When a heat consists of two usable plates, two of the sample ingots shall be selected from the second usable plate poured. When a heat consists of a single usable plate, any three random ingots may be selected. 4.3.1.2.1 If there are less than three ingots in the heat, samples shall be taken representing the top and bottom of all ingots. 4.3.1.3 Strand-Cast Heats: Samples shall be taken from semi-finished or finished product having at least a 3:1 reduction in cross-section from the cast strand, or samples of the as-cast strand similarly reduced, representing the front, middle, and back of both strands when two strands are cast, or of an inside strand and an outside strand when more than two strands are cast. When a single strand is cast, six samples having at least a 3:1 reduction from the cast strand, or samples of the cast strand similarly reduced, representing both ends of the first, middle, and last usable cuts (blooms) of the strand or product shall be taken. 4.3.2 Product Qualification: Samples shall be taken at random from not less than 10% of the pieces of each lot. A lot shall be all product of one size from one heat in one shipment. Not less than three nor more than ten samples shall be selected from a lot, except that if the quantity in the lot is three pieces or less, one sample shall be taken from each piece. 4.4 Reports: The vendor of the product shall include the AMS 2304A frequency-severity rating for each lot in the shipment, in addition to other information required by the applicable material specification. 4.5 Resampling and Retesting: 4.5.1 Product Other Than Slabs and Plates: If any specimen used in the above tests fails to meet the specified requirements, disposition of the heat or lot may be based on the results of testing three additional specimens for each original nonconforming specimen; additional specimens shall be as follows: Copyright SAE International Provided by IHS under license with SAE Not for ResaleNo reproduction or networking permitted without license from IHS - - ` , , ` ` ` , , , , ` ` ` ` - ` - ` , , ` , , ` , ` , , ` - - - AMS 2304A SAE AMS 2304A - 9 - 4.5.1.1 Heats of Top-Poured Ingots: One of the additional specimens shall be taken from the same position from product from each of the two available ingots most immediately adjacent in pouring sequence to that from which the originally nonconforming specimen was taken. The third specimen shall be taken from product of the original nonconforming ingot after additional discard. Should the latter specimen be unacceptable, resampling and retesting of the nonconforming ingot may be