SAE AS 1177A-1993 Nondestructive Inspection Standards for Bolts and Screws《螺栓和螺钉的无损检测标准》.pdf

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4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS1177A AEROSPACE STANDARD AS1177 REV. A Issued 1970-11 Revised 1993-04 Reaffirme

5、d 2012-11 Superseding AS1177 Nondestructive Inspection Standards for Bolts and Screws RATIONALE AS1177A has been reaffirmed to comply with the SAE five-year review policy. 1. SCOPE:1.1 Purpose:To establish the acceptance criteria of surface discontinuities of bolts and screws.1.1.1 This acceptance c

6、riteria establishes the location, number, size, depth, and type of surface discontinuities that are permitted on bolts and screws as revealed by visual, magnetic particle, or fluorescent penetrant inspection.1.2 Application:Applicable to all types of bolts and screws made of low alloy steel (magneti

7、c) or corrosion and heat resistant alloys (magnetic or nonmagnetic) that are primarily used in aerospace propulsion systems.2. REFERENCES:2.1 Applicable Documents:The following publications form a part of this specification to the extent specified herein. The latest issue of SAE publications shall a

8、pply; they are available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.AMS 2640 Magnetic Particle InspectionAMS 2645 Fluorescent Penetrant Inspection2.2 Definitions:2.2.1 DISCONTINUITY: An interruption in the normal physical structure or configuration of a part; such as a lap, seam, in

9、clusion, crack, machining tear, or stringer.SAE AS1177A Page 2 of 9 2.2.2 DEFECT: Any nonconformance of the unit of product with the specified requirements that is severe enough to cause the service of the product not to be fulfilled.2.2.3 LAP: A surface imperfection appearing as a seam or crack, ca

10、used by folding of material during such operations as forming, rolling, or drawing.2.2.4 SEAM: Open surface imperfection that is narrow and continuous, usually straight, running generally parallel to the bolt or screw axis. Seams are generally inherent in the bar from which the bolt or screw is made

11、.2.2.5 INCLUSION: Nonmetallic particles inherent in the material when it was made. These particles may be isolated or distributed in the form of longitudinal stringers.2.2.6 CRACK: A fracture passing through or across grain boundaries. Cracks may occur during heat treatment or may be caused by over-

12、stressing the metal during forging of forming.2.2.7 MACHINING TEAR: A pattern of short, jagged individual cracks, generally at right angles to the direction of machining, frequently the result of improperly set cutting tools, or dull cutting tools.2.2.8 STRINGER: A solid nonmetallic impurity in the

13、metal bar, often the result of inclusions that have been extended during the rolling process.3. TECHNICAL REQUIREMENTS:3.1 Nonpermissible Discontinuities:The following discontinuities shall be cause for rejection of parts inspected by either magnetic particle or fluorescent penetrant inspection proc

14、edures:3.1.1 Discontinuities transverse to grainflow (i.e., at an angle of more than 10 to the axis of the shank), such as cracks, stringers, machining tears, and quench cracks.3.1.2 Longitudinal discontinuities (i.e., at an angle of 10 or less to the axis of the shank) due to discontinuities other

15、than seams, forming laps, and nonmetallic inclusions.3.2 Magnetic Particle Inspection:Parts inspected by magnetic particle inspection shall be considered acceptable if longitudinal discontinuities (i.e., at an angle of 10 or less to the axis of the shank) of seams, forming laps, and nonmetallic incl

16、usions parallel to the grainflow are within the following limits, provided that the separation between discontinuities is not less than 0.06 inch (1.52 mm) in all directions:3.2.1 Sides of Head: There shall be not more than six surface or subsurface discontinuities per head. The length of each disco

17、ntinuity may be the full height of the surface but no discontinuity shall break over either edge to a depth greater than 0.03 inch (0.76 mm) or the equivalent of the basic thread height (see Table 1), whichever is less.SAE AS1177A Page 3 of 9 3.2.2 Shank or Stem: There shall be not more than 10 subs

18、urface and hairline surface discontinuities. The length of any discontinuity may be the full length of the surface but the total length of all discontinuities shall not exceed twice the length of the surface. No discontinuity shall break into a fillet or over an edge.3.2.3 Threads:3.2.3.1 Root defec

19、ts such as laps, seams, notches, slivers, folds, roughness, and oxide scale are not permissible (see Figure 1).3.2.3.2 Multiple laps on the flanks of threads are not permissible regardless of location. Single laps on the flanks of threads that extend toward the root are not permissible (see Figures

20、2 and 3).3.2.3.3 There shall be no laps along the flank of the thread below the pitch diameter (see Figure 4). A single lap is permissible along the flank of the thread above the pitch diameter on either the pressure or nonpressure flank (one lap at any cross-section through the thread) provided it

21、extends toward the crest and generally parallel to the flank (see Figure 4).3.2.3.4 Crest craters, crest laps, or a crest lap in combination with a crest crater are permissible provided that the imperfections do not extend deeper than 20% of the basic thread height (see Table 1) as measured from the

22、 thread crest when the thread major diameter is at minimum size (see Figure 5). The major diameter of the thread shall be measured prior to sectioning. As the major diameter of the thread approaches maximum size, values for depth of crest crater and crest lap imperfections listed in Table 1 may be i

23、ncreased by one-half of the difference between the minimum major diameter and actual major diameter as measured on the part.3.2.4 Top of Head and End of Stem: The number of discontinuities is not restricted but the depth of any individual discontinuity shall not exceed 0.01 inch (0.25 mm). No discon

24、tinuity, except those of 3.2.1, shall break over an edge.3.2.5 Sectioned Specimens: Depth of discontinuities shall be determined by microscopic examination on representative samples of sectioned specimens, polished and etched, of the part discontinuity.3.3 Fluorescent Penetrant Inspection:Parts insp

25、ected by fluorescent penetrant inspection shall be considered acceptable if longitudinal discontinuities (i.e., at an angle of 10 or less to the axis of the shank) of seams and forming laps parallel to the grainflow are within the following limits, provided that the separation between discontinuitie

26、s is not less than 0.06 inch (1.52 mm) in all directions:3.3.1 Sides of Head: There shall be not more than three discontinuities per head. The length of each discontinuity may be the full height of the surface but no discontinuity shall break over either edge to a depth greater than 0.03 inch (0.76

27、mm) or the equivalent of the basic thread height (see Table 1), whichever is less.SAE AS1177A Page 4 of 9 3.3.2 Shank or Stem: There shall be not more than five discontinuities. The length of any discontinuity may be the full length of the surface but the total length of all discontinuities shall no

28、t exceed twice the length of the surface. No discontinuity shall break into a fillet or over an edge.3.3.3 Threads:3.3.3.1 Root defects such as laps, seams, notches, slivers, folds, roughness, and oxide scale are not permissible (see Figure 1).3.3.3.2 Multiple laps on the flanks of threads are not p

29、ermissible regardless of location. Single laps on the flanks of threads that extend toward the root are not permissible (see Figures 2 and 3).3.3.3.3 There shall be no laps along the flank of the thread below the pitch diameter (see Figure 4). A single lap is permissible along the flank of the threa

30、d above the pitch diameter on either the pressure or nonpressure flank (one lap at any cross-section through the thread) provided it extends toward the crest and generally parallel to the flank (see Figure 4).3.3.3.4 Crest craters, crest laps, or a crest lap in combination with a crest crater are pe

31、rmissible provided that the imperfections do not extend deeper than 20% of the basic thread height (see Table 1) as measured from the thread crest when the thread major diameter is at minimum size (see Figure 5). The major diameter of the thread shall be measured prior to sectioning. As the major di

32、ameter of the thread approaches maximum size, values for depth of crest crater and crest lap imperfections listed in Table 1 may be increased by one-half of the difference between the minimum major diameter and actual major diameter as measured on the part.3.3.4 Top of Head and End of Stem: The numb

33、er of discontinuities is not restricted but the depth of any individual discontinuity shall not exceed 0.01 inch (0.25 mm). No discontinuity, except those of 3.3.1, shall break over an edge.3.3.5 Sectioned Specimens: Depth of discontinuities shall be determined by microscopic examination on represen

34、tative samples of sectioned specimens, polished and etched, of the part discontinuity.4. INSPECTION PROCEDURES:4.1 Magnetic Particle Inspection:The inspection shall be conducted in accordance with AMS 2640; any method may be used but resolution of disputed rejections shall be based upon the wet, con

35、tinuous, fluorescent suspension method using amperages shown in 4.1.1 and 4.1.2.4.1.1 Circular Magnetization: 800 to 1000 amperes per square inch (1.24 to 1.55 amperes per square millimeter) of contact area, passed through the part longitudinally.4.1.2 Longitudinal Magnetization: Sufficient to produ

36、ce 5000 ampere-turns per inch (196.85 ampere-turns per mm) of shank diameter with the part placed in a standard solenoid of appropriate size.SAE AS1177A Page 5 of 9 4.2 Fluorescent Penetrant Inspection:The inspection shall be conducted in accordance with AMS 2645.5. NOTES:5.1 Dimensions and amperage

37、s in U.S. customary units are primary; SI units are shown (in parentheses) as the approximate equivalents of the primary units and are presented only for information.5.2 Marginal Indicia:The change bar ( | ) located in the left margin is for the convenience of the user in locating areas where techni

38、cal revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document.PREPARED BY SAE COMMITTEE E-25,GENERAL STANDARDS FOR PROPULSION SYSTEMSSAE AS1177A Page 6 of 9 TABLE 1 - Thread H

39、eightThread Pitches Per Inch nBasic Thread Height (See Note 1) (UN and UNJ) inch20% Basic Thread Height inch80 0.0081 0.001672 0.0090 0.001864 0.0102 0.002056 0.0116 0.002348 0.0135 0.002744 0.0148 0.003040 0.0163 0.003336 0.0181 0.003632 0.0203 0.004128 0.0232 0.004624 0.0271 0.005420 0.0325 0.0065

40、18 0.0361 0.007216 0.0406 0.008114 0.0464 0.009313 0.0500 0.010012 0.0542 0.010811 0.0591 0.011810 0.0650 0.01309 0.0722 0.01448 0.0813 0.0163NOTE 1: Basic thread height is defined as being equivalent to 0.650 times the pitch, where pitch equals 1/n.SAE AS1177A Page 7 of 9 TABLE 1A - Thread Height,

41、SI UnitsThread Pitches Per Inch nBasic Thread Height (See Note 1) (UN and UNJ) mm20% Basic Thread Height mm80 0.206 0.04172 0.229 0.04664 0.251 0.05156 0.259 0.05848 0.343 0.06944 0.376 0.07640 0.414 0.08436 0.460 0.09132 0.516 0.10428 0.589 0.11724 0.688 0.13720 0.826 0.16518 0.917 0.18316 1.031 0.

42、20614 1.179 0.23613 1.270 0.25412 1.377 0.27411 1.501 0.30010 1.651 0.3309 1.834 0.3668 2.065 0.414NOTE 1: Basic thread height is defined as being equivalent to 0.650 times the pitch where pitch equals 25.4/n.SAE AS1177A Page 8 of 9 FIGURE 1 - Root Defects, Rolled ThreadFIGURE 2 - Laps Below PD Extending Toward Root, Rolled ThreadFIGURE 3 - Laps Above PD Extending Toward Root, Rolled ThreadSAE AS1177A Page 9 of 9 FIGURE 4 - Laps Extending Towards Crest, Rolled ThreadFIGURE 5 - Crest Craters and Crest Laps, Rolled Thread