1、AEROSPACERECOMMENDEDPRACTICEARP1341REV.BIssued 1974-12Revised 2001-04Superseding ARP1341ADetermining Decarburization and Carburizationin Finished Parts of Carbon and Low-Alloy Steels1. SCOPE:This document provides a recommended practice for determining decarburization and carburization in heat treat
2、ed carbon and low-alloy steel parts other than case hardened parts. It is not applicable to raw materials.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
3、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.2.1 ASTM Publications:Available from ASTM, 100 Barr Harbor Drive,
4、 West Conshohocken, PA 19428-2959.ASTM E 3 Preparation of Metallographic SpecimensASTM E 384 Microhardness of MaterialsASTM E 407 Microetching Metals and Alloys3. PROCEDURE:3.1 Test Specimens:3.1.1 Integral Specimens: A metallographic specimen shall be removed from the part after the part has been c
5、ompletely heat treated. Care should be taken in removing the specimen to avoid overheating the specimen.Reaffirmed 2010-05SAE 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
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9、g/technical/standards/ARP1341BSAE ARP1341 Revision B- 2 -3.1.2 Specimens from Separate Samples: A metallographic specimen shall be taken from a sample processed with the part. The sample shall be of the same grade of steel as the part, have the same surface condition as the part, and preferably be f
10、rom the same heat of steel as the part. The sample shall be hardened and tempered with the part represented, using the specified procedure, except that, when specified, the sample shall be hardened but not tempered (See 5.1).3.2 Preparation of Test Samples:The metallographic specimen shall be taken
11、transverse to the surface of the part of sample and shall be at least 0.250 inch (6.35 mm) thick. The specimen shall be prepared in accordance with ASTM E 3 and E 407.3.3 Examination:3.3.1 Visual: The etched specimen shall be examined under a microscope at 100X magnification, using a calibrated eyep
12、iece.3.3.2 Microhardness Survey: A microhardness traverse shall be made with a Knoop indenter and 200 grams load in accordance with ASTM E 384. A minimum of three hardness readings shall be taken to establish the specimen base hardness in an area at least 0.125 inch (3.18 mm) from the outside surfac
13、e or at midradius or midthickness, whichever is less. Readings shall be taken at 0.001 inch (0.03 mm) intervals starting at 0.002 inch (0.05 mm) from the outside surface in a staggered pattern until the preestablished base hardness is reached. The hardness readings shall be plotted versus distance f
14、rom the outside surface as shown in Figure 1.4. DECARBURIZATION AND CARBURIZATION DETERMINATION:4.1 Complete Decarburization (Free Ferrite):Shall be determined by visual examination as in 3.3.1. The maximum and average depths shall be reported.4.2 Total Decarburization (Complete plus partial):Shall
15、be determined by microhardness survey as in 3.3.2. The depth of total decarburization shall beas follows:4.2.1 Hardened and Tempered Specimens: That depth below the surface at which the hardness is no more than 20 units on the Knoop scale lower than the base hardness, as illustrated in Figure 1.4.2.
16、2 Hardened Specimens: That depth below the surface at which the hardness is no more than 30 units on the Knoop scale lower than the base hardness.SAE ARP1341 Revision B- 3 -FIGURE 1 - Typical Microhardness SurveySAE ARP1341 Revision B- 4 -4.3 Carburization:Any hardness reading near the edge which is
17、 more than 10 units on the Knoop scale higher than the base hardness shall be evidence of carburization.5. NOTES:5.1 The change bar ( l ) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous i
18、ssue of this specification. An (R) symbol to the left of the document title indicates a complete revision of the specification, including technical revisions. Change bars and (R) are not used in original publications, nor in specifications that contain editorial changes only.5.2 Condition of Sample:Testing of hardened specimens (4.2.2) will result in a greater apparent depth of decarburization than similar testing of hardened and tempered specimens (4.2.1). Testing of hardened specimens may be specified when a more sensitive test is desired.PREPARED UNDER THE JURISDICTION OF AMS COMMITTEE “B“
