SAE AS 7452B-2014 Bolts and Screws Steel Low Alloy Heat Treated Roll Threaded《滚动螺纹低合金热处理的钢制螺栓和螺钉》.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/AS7452BAEROSPACESTANDARDAS7452 REV. B Issued 1991-02 Reaffirmed 2004-07 Revised 2

5、014-08 Superseding AS7452ABolts and Screws, Steel, Low Alloy Heat Treated, Roll Threaded FSC 5306 RATIONALE Revise sampling values for destructive tests to be in accordance with current practice on similar bolt specifications and clarify requirements for cold working fillet radii. 1. SCOPE 1.1 Type

6、This procurement specification covers aircraft quality bolts and screws made from a low alloy steel of the type identified under the Unified Numbering System as UNS G87400, and of a series of room temperature tensile strengths ranging from 125 000 to 185 000 psi. 1.2 Application Primarily for aerosp

7、ace propulsion system applications where good strength is required and the part is protected against corrosion. 1.2.1 Safety - Hazardous Materials While the materials, methods, applications, and processes described or referenced in this specification may involve the use of hazardous materials, this

8、specification does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved

9、. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event o

10、f conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. SAE INTERNATIONAL AS7452B Page 2 of 21 2.1.1 SAE Publicat

11、ions Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.AMS2750 Pyrometry AMS6322 Steel Bars, Forgings, and Rings, 0.50Cr - 0.55Ni - 0.25Mo (0.38 - 0.43C) (SAE 8740) AMS6327 Steel B

12、ars and Forgings, 0.50Cr - 0.55Ni - 0.25Mo (0.38 - 0.43C) (SAE 8740) Heat Treated, 125 ksi (862 MPa) Tensile Strength AS1132 Bolts, Screws and Nuts - External Wrenching, UNJ Thread, Inch - Design Standard AS3062 Bolts, Screws and Studs, Screw Thread Requirements AS3063 Bolts, Screws, and Studs, Geom

13、etric Control Requirements AS8879 Screw Threads - UNJ Profile, Inch, Controlled Radius Root with Increased Minor Diameter 2.1.2 ASTM PublicationsAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM E8/E8M Stan

14、dard Test Method for Tension Testing of Metallic Materials ASTM E140 Standard Hardness Conversion Tables for Metals ASTM D3951 Standard Practice for Commercial Packaging ASTM E1444/E1444M Standard Practice for Magnetic Particle Testing 2.1.3 ASME PublicationsAvailable from American Society of Mechan

15、ical Engineers, 22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007-2900, Tel: 973-882-1170, www.asme.org.ASME B46.1 Surface Texture (Surface roughness, Waviness, and Lay) 2.1.4 AIA Publications Available from Aerospace Industries Association, 1000 Wilson Boulevard, Suite 1700, Arlington, VA 22209-3928

16、, Tel: 703-358-1000, www.aia-aerospace.org.NASM1312-6 Fastener Test Methods, Method 6, Hardness NASM1312-8 Fastener Test Methods, Method 8, Tensile Strength NASM1312-12 Fastener Test Methods, Method 12, Plating Thickness SAE INTERNATIONAL AS7452B Page 3 of 21 2.2 Definitions BURR: A rough edge or ri

17、dge left on the metal due to a cutting, grinding, piercing or blanking operation. COLD ROLLING: Forming material below the recrystallization temperature. CRACK: Rupture in the material which may extend in any direction and which may be intercrystalline or transcrystalline in character. DEFECT: Any n

18、onconformance of the unit of product with specified requirements. DISCONTINUITY: An interruption in the normal physical structure or configuration of a part, such as a lap, seam, inclusion, crack, machining tear, or stringer. INCLUSION: Nonmetallic particles originating from the material making proc

19、ess. They may exist as discrete particles or strings of particles extending longitudinally. LAP: Surface imperfection caused by folding over metal fins or sharp corners and then rolling or forging them into the surface. The allowable lap depth shall not exceed the limit specified herein. The minimum

20、 condition that shall be rated as a lap is a fold having its length equal to or greater than three times its width with a depth of 0.0005 inch when viewed at 200X magnification. MACHINING TEAR: A pattern of short, jagged individual cracks, generally at right angles to the direction of machining, fre

21、quently the result of improperly set cutting tools, or dull cutting tools. PRODUCTION INSPECTION LOT: Shall be all finished parts of the same part number, made from a single heat of alloy, heat treated at the same time to the same specified condition, produced as one continuous run, and submitted fo

22、r vendors inspection at the same time. SEAM: Longitudinal surface imperfection in the form of an unweld, open fold in the material. STRINGER: A solid nonmetallic impurity in the metal bar, often the result of inclusions that have been extended during the rolling process. TIGHT BURR: A burr closely c

23、ompacted and binding in the periphery of the part without any loose ends and is within the dimensional limits of the part. 2.3 Unit Symbols A - ampere F - degree Fahrenheit % - percent (1% = 1/100) lbf - pounds force psi - pounds force per square inch sp gr - specific gravity 3. TECHNICAL REQUIREMEN

24、TS 3.1 Material Shall be AMS6322, or AMS6327 steel, unless otherwise specified on the part drawing. SAE INTERNATIONAL AS7452B Page 4 of 21 3.2 Design Finished (completely manufactured) parts shall conform to the following requirements: 3.2.1 Dimensions The dimensions of finished parts, after all pro

25、cessing, including plating, shall conform to the part drawing. Dimensions apply after plating but before coating with dry film lubricants. 3.2.2 Surface Texture Surface texture of finished parts, prior to plating or coating, shall conform to the requirements as specified on the part drawing, determi

26、ned in accordance with ASME B46.1. 3.2.3 Threads Screw thread UNJ profile and dimensions shall be in accordance with AS8879, unless otherwise specified on the part drawing. 3.2.3.1 Incomplete Threads Incomplete threads are permissible at the chamfered end and the juncture of the unthreaded portion o

27、f the shank or adjacent to the head as specified in AS3062. 3.2.3.2 Chamfer The entering end of the thread shall be chamfered as specified on the part drawing. 3.2.4 Geometric Tolerances Part features shall be within the geometric tolerances specified on the part drawing and, where applicable, contr

28、olled in accordance with AS3063. 3.3 Fabrication 3.3.1 Blanks Heads shall be formed by hot or cold forging or machining. Lightening holes may be produced by any suitable method. Wrenching recesses may be forged or machined. Flash or chip clearance in machined recesses shall not cause recess dimensio

29、ns to exceed the specified limits. 3.3.2 Heat Treatment Headed and machined blanks, unless machined from heat treated stock, shall, before finishing the shank and the bearing surface of the head, cold working the head-to-shank fillet radius when specified, and rolling the threads, be heat treated as

30、 follows: 3.3.2.1 Heating Equipment Furnaces may be any type ensuring uniform temperature throughout the parts being heated and shall be equipped with, and operated by, automatic temperature controllers and data recorders conforming to AMS2750. The heating medium or atmosphere shall cause no surface

31、 hardening by carburizing or nitriding nor decarburization other than that permitted by 3.7.2.2 and 3.7.2.3. SAE INTERNATIONAL AS7452B Page 5 of 21 3.3.2.2 Hardening Blanks of AMS6322 shall be uniformly heated to a temperature within the range 1500 to 1550 F, held at heat for not less than 15 minute

32、s, and quenched in oil. For other steels, when specified, the temperature shall be as agreed by purchaser and vendor. 3.3.2.3 Tempering Hardened blanks shall be tempered by heating uniformly to a temperature necessary to produce the specified hardness and microstructure, holding at heat for not less

33、 than 1 hour, and cooling. 3.3.3 Oxide and Decarburization Removal Surface oxide, oxide penetration, and decarburization except as permitted in 3.7.2.3, resulting from prior heat treatment, shall be removed from the full body diameter and bearing surface of the head of the heat treated blanks prior

34、to cold working the under head fillet radius when specified and rolling the threads. The oxide removal process shall produce no intergranular attack or corrosion of the blanks. The metal removed from the bearing surface of the head and the full body diameter of the shank shall be as little as practi

35、cable to obtain a clean, smooth surface and, in no case, shall be so great as to produce more cutting of flow lines in the head-to-shank junction of forged headed parts than shown in Figure 1B. 3.3.4 Cold Working of Fillet Radius After removal of oxide and decarburization as in 3.3.3, the head-to-sh

36、ank fillet radius of headed parts having the radius complete throughout the circumference of the part, when specified, shall be cold worked. The cold rolling shall be sufficient to remove all visual evidence of grinding or tool marks. Distortion due to cold working shall conform to Figure 2, unless

37、otherwise specified on the part drawing. It shall not raise metal more than 0.002 inch above the contour at “A” or depress metal more than 0.002 inch below the contour at “B” as shown in Figure 2; distorted areas shall not extend beyond “C” as shown in Figure 2. In configurations having an undercut

38、associated with the fillet radius, the cold working will be required only for 90 degrees of fillet arc, starting at the point of tangency of the fillet radius and the bearing surface of the head. Forshouldered bolts, having an unthreaded shank diameter larger than the thread major diameter and havin

39、g an undercut associated with the fillet between the threaded shank and the shoulder of the unthreaded shank, the cold working will be required only for 90 degrees of fillet arc, starting at the point of tangency of the fillet radius and the shouldered surface ofthe unthreaded shank. For parts with

40、compound fillet radii between head and shank, cold work only the radius that blends with the head. 3.3.5 Thread Rolling Threads shall be formed on the heat treated and finished blanks by a single rolling process after removal of oxide and decarburization as in 3.3.3. 3.4 Product Marking Each part sh

41、all be identification marked as specified by the part drawing. The markings may be formed by forging or stamping, raised or depressed not more than 0.010 inch maximum, with rounded root form on depressed characters. 3.5 Plating Where required, surfaces shall be plated as specified by the part drawin

42、g. SAE INTERNATIONAL AS7452B Page 6 of 21 3.6 Mechanical Properties Parts shall conform to the requirements of 3.6.1 and 3.6.2. Threaded members of gripping fixtures for tensile test shall be of sufficient size and strength to develop the full strength of the part without stripping the thread. The l

43、oaded portion of theshank shall have two to three full thread turns from the thread runout exposed between the loading fixtures during the tensile test. Finished parts shall be tested in accordance with the following applicable test methods: Hardness: NASM1312-6 Room Temperature Ultimate Tensile Str

44、ength: NASM1312-8 3.6.1 Ultimate Tensile Strength at Room Temperature 3.6.1.1 Finished Parts Parts having hardness not lower than 26 HRC shall have an ultimate tensile load not lower than that specified in Table 3 and shall be tested to failure, first measuring and recording the maximum tensile load

45、 achieved. If the size or shape of the part is such that failure would occur outside the threaded section but the part can be tested satisfactorily, such as parts having a shank diameter equal to or less than the thread root diameter or having an undercut, parts shall conform to only the tensile req

46、uirements of 3.6.1.2; for such parts, the diameter of the area on which stress is based shall be the actual measured minimum diameter of the part. Tension fasteners with either standard double hexagon or hexagon type heads having a minimum metal condition in the head equal to the design parameters s

47、pecified in AS1132 shall not fracture in the head-to-shank fillet radius except when this radius is associated with the undercut or with a shank diameter less than the minimum pitch diameter of the thread. 3.6.1.2 Machined Test Specimens If the size or shape of the part is such that a tensile test c

48、annot be made on the part, tensile tests shall be conducted in accordance with ASTM E8/E8M on specimens prepared as in 4.4. Such specimens shall meet requirements in Table 1: TABLE 1 - TENSILE PROPERTIES OF TEST SPECIMENS Minimum Hardness of Specified Range HRC UltimateTensile Strength psi, minimum

49、Elongation in 2 inches or 4D %, minimum Reduction of Area %, minimum 26 125 000 15 52 32 145 000 13 50 36 165 000 12 47 40 185 000 10 43 3.6.1.2.1 When permitted by purchaser, hardness tests on the end of parts may be substituted for tensile tests of machined specimens. 3.6.2 Hardness Hardness shall be uniform within the range 26 to 32 HRC, unless otherwise specified on the part drawing, but hardness of the threaded section and of the head-t