Standard Specification for Carbon and Alloy Steel Externally Threaded Metric Fasteners 1

Transcription

1 Designation: F 568M 04 METRIC Standard Specification for Carbon and lloy Steel Externally Threaded Metric Fasteners This standard is issued under the fixed designation F 568M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. number in parentheses indicates the year of last reapproval. superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.. Scope*. This specification covers chemical and mechanical requirements for nine property classes of carbon and alloy steel externally threaded metric fasteners in noal thread diameters M.6 through M00 suited for use in general engineering applications.. This specification does not cover dimensional requirements for fasteners of any property class. When referencing this specification for procurement purposes, it is mandatory that size, type, style, and any special dimensions of the product be additionally specified... In case of any conflict in requirements, the requirements of the individual product specification shall take precedence over those of this general specification... The purchaser may specify additional requirements which do not negate any of the provisions of this general specification or of the individual product specification. Such additional requirements, the acceptance of which are subject to negotiation with the supplier, must be included in the order information (see Section 3)..3 Requirements for seven of the nine property classes, 4.6, 4.8, 5.8, 8.8, 9.8, 0.9, and.9, are essentially identical with requirements given for these classes in ISO The other two, and 0.9.3, are not recognized in ISO standards..4 Classes and bolts, screws, and studs have atmospheric corrosion resistance and weathering characteristics comparable to those of the steels covered in Specification 588/ 588M. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition. See 5.. When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications..5 When agreed on by the purchaser, Class 5.8 fasteners may be supplied when either Classes 4.6 or 4.8 are ordered; Class 4.8 may be supplied when Class 4.6 is ordered; Class may be supplied when Class 8.8 is ordered; and Class may be supplied when Class 0.9 is ordered..6 The product size range for which each property class is applicable is given in Table and Table on chemical composition requirements, and the mechanical requirements table (see Table 3)..7 ppendix X gives conversion guidance to assist designers and purchasers in the selection of a suitable property class..8 ppendix X explains the significance of the property class designation numerals.. Referenced Documents. STM Standards: 53/ 53M Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware 307 Specification for Carbon Steel Bolts and Studs, psi Strength 35 Specification for Structural Bolts, Steel, Heat Treated, 0/05 ksi Minimum Strength 35M Specification for Structural Bolts, Steel, Heat Treated 830 Mpa Minimum Strength [Metric] 354 Specification for Quenched and Tempered lloy Steel Bolts, Studs, and Other Externally Threaded Fasteners 449 Specification for Quenched and Tempered Steel Bolts and Studs 490 Specification for Structural Bolts, lloy Steel, Heat Treated, 50 ksi Minimum Strength 490M Specification for High-Strength Steel Bolts, Classes 0.9 and 0.9.3, for Structural Steel Joints [Metric] 574 Specification for lloy Steel Socket-Head Cap Screws This specification is under the jurisdiction of STM Committee F6 on Fasteners and is the direct responsibility of Subcommittee F6.0 on Steel Bolts, Nuts, Rivets and Washers. Current edition approved ug., 004. Published ugust 004. Originally approved in 979. Last previous edition approved in 00 as F 568M 0. For referenced STM standards, visit the STM website, or contact STM Customer Service at service@astm.org. For nnual Book of STM Standards volume information, refer to the standard s Document Summary page on the STM website. * Summary of Changes section appears at the end of this standard. Copyright STM International, 00 Barr Harbor Drive, PO Box C700, West Conshohocken, P , United States.

2 TBLE Chemical Composition Requirements Property Class Noal Product Diameter, mm Material and Treatment Product nalysis Element (% by weight) Tempering Temperature, C C Mn B P S Min Max Min Min Max Max Min 4.6 M5 M00 low or medium carbon steel M.6 M6 low or medium carbon steel, partially or fully annealed as required M5 M4 low or medium carbon steel, cold worked M0 M80 medium carbon steel, product is quenched and tempered B C M0 M36 low carbon martensite steel, product is quenched and tempered D M0 M36 atmospheric corrosion resistant steel, product is quenched and see Table 45 tempered 9.8 M.6 M6 medium carbon steel, product is quenched and tempered M.6 M6 low carbon martensite steel, product is quenched and tempered D M5 M0 medium carbon steel, product is quenched and tempered E,F M5 M00 medium carbon alloy steel, product is quenched and tempered E M5 M36 low carbon martensite steel, product is quenched and tempered E,F M6 M36 atmospheric corrosion resistant steel, product is quenched and see Table 45 tempered E.9 M.6 M00 alloy steel, product is quenched and tempered E,G For studs only, sulfur content may be 0.33 %, max. B t the manufacturer s option, medium-carbon-alloy steel may be used for noal thread diameters over M4. C For studs only, sulfur content may be 0.3 %, max. D Products made using this material shall be specially identified as specified in Section 5. E Steel for Classes 0.9, 0.9.3, and.9 products shall be fine grain and have a hardenability that will achieve a structure of approximately 90 % martensite at the center of a transverse section one diameter from the threaded end of the product after oil quenching. F Carbon steel may be used at the option of the manufacturer for products of noal thread diameters M and smaller. When approved by the purchaser, carbon steel may be used for products of diameters larger than M through M0, inclusive. G lloy steel shall be used. Steel is considered to be alloy by the merican Iron and Steel Institute when the maximum of the range given for the content of alloying elements exceeds one or more of the following limits: manganese,.65 %; silicon, 0.60 %; copper, 0.60 %; or in which a definite range or a definite imum quantity of any of the following elements is specified or required within the limits of the recognized field of constructional alloy steels: aluum, chromium up to 3.99 %, cobalt, columbium, molybdenum, nickel, titanium, tungsten, vanadium, zirconium, or any other alloying elements added to obtain a desired alloying effect. 588/ 588M Specification for High-Strength Low-lloy Structural Steel with 50 ksi [345 MPa] Minimum Yield Point to 4-in. [00-mm] Thick 75 Test s, Practices, and Terology for Chemical nalysis of Steel Products B 695 Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel D 395 Practice for Commercial Packaging F 606 Test s for Detering the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, and Rivets F 606M Test s for Detering the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, and Rivets [Metric] F 788/F 788M Specification for Surface Discontinuities of Bolts, Screws, and Studs, Inch and Metric Series F 470 Guide for Fastener Sampling for Specified Mechanical Properties and Performance Requirements G 0 Guide for Estimating the tmospheric Corrosion Resistance of Low-lloy Steels. ISO Standard: 3 ISO 898-, Mechanical Properties of Fasteners, Part I, Bolts, Screws, and Studs.3 SME Standards: 3 B 8..3.M Metric Hex Cap Screws B 8..3.M Metric Formed Hex Screws B M Metric Heavy Hex Screws B M Metric Hex Flange Screws 3 vailable from merican National Standards Institute (NSI), 5 W. 43rd St., 4th Floor, New York, NY B M Metric Hex Bolts B M Metric Heavy Hex Bolts B 8.5..M Metric Round Head Short Square Neck Bolts B 8.5..M Metric Round Head Square Neck Bolts 3. Ordering Information 3. Orders for products referencing this specification shall include the following: 3.. Quantity (number of pieces), 3.. Name of product (that is, type and style of bolt, screw, or stud), 3..3 Dimensions, including noal thread diameter, thread pitch, and length (see Section 7), 3..4 Property class, 3..5 Zinc Coating Specify the zinc coating process required, for example, hot dip, mechanically deposited, or no preference (see 4.5), 3..6 Other Finishes Specify other protective finish, if required, 3..7 STM designation and year of issue, and 3..8 ny special requirements (for example, mechanical requirements, see Tables 3 and 4, or proof load testing, see Tables 5 and 6; stud marking, see 5..3; additional testing, see Section 9) Test reports if required, see Section Materials and Manufacture 4. Steel for bolts, screws, and studs shall be made by the open-hearth, basic-oxygen, or electric-furnace process. 4. Heading Practice:

3 Element Carbon: Manganese: Phosphorus: Sulfur: Silicon: Copper: Nickel: Chromium: Vanadium: Molybdenum: Titanium: TBLE Chemical Composition Requirements for Classes and Composition, % B C D E F max max max max max 0.07 max F568M max max max max 0. max 0.05 max , B, C, D, E, and F are types of material used for Property Classes and bolts, screws, and studs. Selection of a composition shall be at the option of the product manufacturer except that sizes M0 and larger shall conform to Composition or B only. TBLE 3 Mechanical Requirements for Bolts, Screws, and Studs Property Class Noal Diameter of Product Full Size Bolts, Screws, and Studs Proof Load Length Measurement, MPa Yield Strength, MPa MPa Machined Test Specimens of Bolts, Screws, and Studs Yield MPa B MPa Elongation, % Reduction of rea, % Surface Hardness Rockwell 30N Rockwell Product Hardness Vickers Min Min Min Min Min Max Min Max Min Max 4.6 M5 M C B67 B M.6 M B7 B M5 M4 D B8 B M0 M C3 C M0 M C3 C M.6 M C7 C M5 M C33 C M6 M C33 C E M.6 M C38 C Proof load and tensile strength values for full size products of each property class are given in Table 5. B Yield strength is stress at which a permanent set of 0. % of gage length occurs. C Yield point shall apply instead of yield strength at 0. % offset for Class 4.6 products. D Class 5.8 applies only to bolts and screws with lengths 50 mm and shorter and to studs of all lengths. E Caution is advised when considering the use of Class.9 bolts, screws, and studs. Capability of the bolt manufacturer, as well as the anticipated in-use environment, should be considered. High-strength products of Class.9 require rigid control of heat-treating operations and careful monitoring of as-quenched hardness, surface discontinuities, depth of partial decarburization, and freedom from carburization. Some environments may cause stress corrosion cracking of nonplated as well as electroplated products. 3

4 TBLE 4 Mechanical Testing Requirements for Bolts, Screws, and Studs 4.. s other than upsetting or extrusion, or both, are permitted only by special agreement between purchaser and producer. 4.. Class 4.6 may be hot or cold headed at the option of the manufacturer Classes 4.8, 5.8, 8.8, 8.8.3, 9.8, 0.9, 0.9.3, and.9 bolts and screws in noal thread diameters up to M0 inclusive with lengths up to ten times the noal product size or 50 mm, whichever is shorter, shall be cold headed, except that they may be hot headed by special agreement with the purchaser. Larger diameters and longer lengths may be cold or hot headed at the option of the manufacturer. 4.3 Threading Practice: 4.3. Threads on Class 4.6 bolts and screws and on all classes of studs may be cut, rolled, or ground at the option of the manufacturer Threads on Classes 4.8, 5.8, 8.8, 8.8.3, 9.8, 0.9, 0.9.3, and.9 bolts and screws in noal thread diameters up to M0 inclusive, and product lengths up to 50 mm inclusive, shall be roll threaded, except by special agreement with the purchaser. Threads of these classes on bolts and screws larger than M0 or longer than 50 mm or both, may be rolled, cut, or ground at the option of the manufacturer. 4.4 Heat Treatment: 4.4. Class 4.6 bolts and screws and Classes 4.6, 4.8, and 5.8 studs need not be heat treated Classes 4.8 and 5.8 bolts and screws shall be stress relieved if necessary to assure the soundness of the head to shank junction. When stress relieving is specified by the purchaser, Class 5.8 bolts and screws shall be stress relieved at a imum stress-relief temperature of 470 C. Where higher stress-relief temperatures are necessary to relieve stresses in severely upset heads, mechanical requirements shall be agreed upon between the purchaser and producer Classes 8.8, 8.8.3, and 9.8 bolts, screws, and studs shall be heat treated by quenching in a liquid medium from above the transformation temperature and reheating to the tempering temperature given in Table. 4

5 TBLE 5 Proof Load and Strength Values, kn Noal Product Diameter and Thread Pitch Stress rea, B mm Class 4.6 Class 4.8 Class 5.8 Class 8.8 and Class 9.8 Classes 0.9 and Class.9 Proof Load C Proof Load Proof Load Proof Load Proof Load Proof Load Proof Load M M M M M M M M M M M M M D D D M M 3.5 E M M7 3 3 E M M M M M M M M M M Proof loads and tensile strengths are computed by multiplying the stresses given in Table 3 by the stress area of the thread. B Stress area, mm = (D P), where D = noal product size, mm, and P = thread pitch, mm. C Proof load,, is the length measurement method as described in 3..3 of Test s F 606. Proof load,, is the yield strength method as described in 3..5 of Test s F 606. D For Classes 8.8 and sizes M6 and smaller are not covered by Specification F 568M. Class 9.8 may be suitable for applications requiring sizes M6 and smaller after consideration of design parameters, application and service environment. E M and M7 are standard sizes for high-strength structural bolts only as covered in Specifications 35M and 490M. 5

6 TBLE 6 Tension Test Wedge ngle Product Property Class Noal Product Diameter, (D) Wedge ngle, Hex bolts and screws threaded D or closer to underside of head 4.6, 4.8, 5.8 through M4 0 over M , 8.8.3, 9.8, 0.9, through M0 6 over M0 4 Hex bolts and screws with unthreaded length greater than D 4.6, 4.8, 5.8, 8.8, 8.8.3, 9.8, 0.9, through M4 0 over M4 6 Hex bolts and screws threaded D or closer to underside of head.9 all 4 Hex bolts and screws with unthreaded length greater than D.9 through M0 6 over M0 4 Hex flange screws 5.8, 9.8, 0.9 all 6 Studs all through M0 6 over M Classes 0.9, 0.9.3, and.9 bolts, screws, and studs shall be heat treated by quenching in oil from above the transformation temperature and reheating to the tempering temperature given in Table Tempering-Temperature-udit Test This test is a means for checking whether products were tempered at the specified temperature. The hardness (mean hardness of three hardness readings) of a bolt, screw, or stud as manufactured shall be measured. The product shall then be retempered for a imum of 30 per 5 mm of noal diameter, but not less than 30, at a temperature 0 C less than the imum tempering temperature specified for the property class and material in Table. The hardness of the retempered product shall then be measured. The difference between the hardness of the product before and after retempering shall not exceed 0 HV points. 4.5 Zinc Coatings, Hot-Dip, and Mechanically Deposited: 4.5. When zinc-coated fasteners are required, the purchaser shall specify the zinc coating process, for example, hot dip, mechanically deposited, or no preference When hot-dip is specified, the fasteners shall be zinc coated by the hot-dip process in accordance with the requirements of Class C of Specification 53/ 53M When mechanically deposited is specified, the fasteners shall be zinc coated by the mechanical deposition process in accordance with the requirements of Class 50 of Specification B When no preference is specified, the supplier may furnish either a hot dip zinc coating in accordance with Specification 53/ 53M, Class C, or a mechanically deposited zinc coating in accordance with Specification B 695, Class 50. ll components of mating fasteners (for example, bolts, nuts, and washers) shall be coated by the same zinc coating process, and the suppliers option is limited to one process per item with no mixed processes in a lot. 4.6 Bolts, screws, and studs of Classes 0.9 and.9 should not be hot-dip zinc-coated. NOTE Research conducted on bolts with properties equivalent to Class 0.9 indicated that hydrogen-stress corrosion cracking may occur in hot-dip zinc-coated fasteners of Classes 0.9 and Chemical Composition 5. For all classes except and 0.9.3, the bolts, screws, and studs shall conform to the chemical composition specified in Table. 5. Classes and 0.9.3: 5.. Sizes M0 and smaller shall conform to any one of the compositions (, B, C, D, E, or F) specified in Table, at the suppliers option. 5.. Sizes larger than M0 shall conform to Compositions or B specified in Table, at the suppliers option See Guide G 0 for methods of estimation corrosion resistance of low alloy steels. 5.3 Material analyses may be made by the purchaser from finished products representing each lot. The chemical composition thus detered shall conform to the requirements specified for the product analysis in Table and Table. 5.4 Use of heats of steel to which bismuth, selenium, tellurium, or lead has been intentionally added shall not be permitted. 5.5 Chemical analyses shall be performed in accordance with Test s, Practices, and Terology Mechanical Properties 6. Bolts, screws, and studs shall be tested in accordance with the mechanical testing requirements for the applicable type, property class, size, and length of product as specified in Table 4, and shall meet the mechanical requirements specified for that product in Tables For products on which both hardness and tension tests are performed, acceptance based on tensile requirements shall take precedence over low readings of hardness tests. 7. Dimensions 7. The dimensions shall be in accordance with the applicable SME standard below, as specified by the purchaser on the purchase order. 7.. B8..3.M Metric Hex Cap Screws, 7.. B8..3.M Metric Formed Hex Screws, 7..3 B8..3.3M Metric Heavy Hex Screws, 7..4 B8..3.4M Metric Hex Flange Screws, 6

7 7..5 B8..3.5M Metric Hex Bolts, 7..6 B8..3.6M Metric Heavy Hex Bolts, 7..7 B8.5..M Metric Round Head Short Square Neck Bolts, and 7..8 B8.5..M Metric Round Head Square Neck Bolts. 8. Workmanship 8. Surface discontinuity limits shall be in accordance with Specification F 788/F 788M. 9. Number of Tests 9. Testing Responsibility: 9.. Each lot shall be tested by the manufacturer prior to shipment in accordance with the production lot identificationcontrol quality assurance plan in When fasteners are furnished by a source other than the manufacturer, the responsible party, as defined in. shall be responsible for ensuring that all tests have been performed and the fasteners comply with the requirements of this specification. 9. Purpose of Lot Inspection The purpose of a lot inspection program is to ensure that each lot conforms to the requirements of this specification. For such a plan to be fully effective, it is essential that secondary processors, distributors, and purchasers maintain the identification and integrity of each lot until the product is installed. 9.3 Lot Processing ll fasteners shall be processed in accordance with a lot identification-control quality assurance plan. The manufacturer, secondary processors, and distributors shall identify and maintain the integrity of each lot of fasteners from raw material selection through all processing operations and treatments to final packing and shipment. Each lot shall be assigned its own lot identification number, each lot shall be tested, and the inspection test reports for each lot shall be retained. 9.4 Lot Definition: 9.4. Standard Lot lot shall be a quantity of uniquely identified fastener product of the same noal size and length produced consecutively at the initial operations from a single mill heat of material and heat treatment lot and processed at one time by the same process in the same manner so that statistical sampling is valid. The identity of the lot and lot integrity shall be maintained throughout all subsequent operations and packaging Lots of 000 Pieces or Fewer Orders for 000 pieces or fewer of the same noal diameter but varying in length that has been processed essentially under the same conditions from the same mill heat of material and submitted for inspection at one time are considered a lot for purposes of preparing a single test report. 9.5 Number of Tests The imum number of tests from each lot for the tests specified below shall be as follows: Tests Number of Tests in ccordance With Hardness and Strength Guide F 470 Proof Load Guide F 470 Coating Weight/Thickness The referenced coating specification B Surface Discontinuities Guide F 470 Proof load tests required only when specified on the original inquiry and purchase order. See Table 4. B Use Guide F 470 if the coating specification does not specify a testing frequency. 0. Test s 0. Bolts, screws, and studs shall be tested in accordance with the methods described in Test s F 606M, with tension test wedge angles as specified in Table 6.. Inspection. If the inspection described in. is required by the purchaser, it shall be specified in the inquiry, order, or contract.. The inspector representing the purchaser shall have free entry to all parts of the manufacturer s works that concern the manufacture of the material ordered. The manufacturer shall afford the inspector all reasonable facilities to satisfy the inspector that the material is being furnished in accordance with this specification. ll tests and inspection shall be made prior to shipment, and shall be so conducted as not to interfere unnecessarily with the operation of the work.. Responsibility. The party responsible for the fastener shall be the organization that supplies the fastener to the purchaser. 3. Rejection and Rehearing 3. Disposition of nonconforg material shall be in accordance with Guide F 470 section titled Disposition of Nonconforg Lots. 4. Certification 4. When specified on the purchase order, the manufacturer or supplier, whichever is the responsible party in accordance with Section, shall furnish the purchaser a test report that includes the following: 4.. Product description, grade, quantity, STM specification number, and issue date; 4.. and heat number; 4..3 Results of the hardness and tensile tests; 4..4 Statement of compliance with protective coating specification; 4..5 Statement of compliance with the surface discontinuity requirements of Specification F 788/F 788M; 4..6 Statement of compliance with dimensional and thread fit specifications; 4..7 Report, describe, or illustrate manufacturer markings; 4..8 Lot number, purchase order number, and date shipped; 4..9 Complete mailing address of responsible party; and 4..0 Title and signature of the individual assigned certification responsibility by the company officers. 4. Failure to include all the required information on the test report shall be cause for rejection. 5. Product Marking 5. Bolts and Screws: 5.. Bolts and screws of noal thread diameters smaller than M5 need not be marked. dditionally, slotted and recessed screws of noal thread diameters M5 and larger need not be marked. 7

8 5.. Bolts and screws, except those covered in 5.., shall be marked permanently and clearly to identify the property class and the manufacturer. The property class symbols shall be as given in Table 7. The manufacturer s identification symbol shall be of his design For Classes and 0.9.3, the manufacturer may add other distinguishing marks indicating that the bolt or screw is atmospheric corrosion resistant and of a weathering grade of steel Markings shall be located on the top of the head with the base of the property class symbols positioned toward the closest periphery of the head. Markings may be either raised or depressed at the option of the manufacturer. lternatively, for hex head products, the markings may be indented on the side Property Class TBLE 7 Specification 35M Bolts Property Class Identification Symbols Specification 490M Bolts Identification Symbol Other Bolts and Screws M4 and Smaller Studs M5 to M0 incl. M and Larger B 8S S B B 0S 0.9 h S D.9 Not applicable. B Products made of low-carbon martensite steel shall be additionally marked by underlining the property class symbol. of the head with the base of the property class symbols positioned toward the bearing surface Metric bolts and screws shall not be marked with radial line symbols. 5. Studs: 5.. Studs shall be marked permanently and clearly to identify the property class. The property class symbols and sizes to be marked shall be as given in Table Markings shall be located on the extreme end of the stud and may be raised or depressed at the option of the manufacturer. For studs with an interference-fit thread, the markings shall be located on the nut end When ordered by the purchaser, studs shall be marked on both ends. 6. Packaging and Package Marking 6. Packaging: 6.. Unless otherwise specified, packaging shall be in accordance with Practice D When special packaging requirements are required, they shall be defined at the time of the inquiry and order. 6. Package Marking: 6.. Each shipping unit shall include or be plainly marked with the following information: 6... STM designation and type, 6... Size, Name and brand or trademark of the manufacturer, Number of pieces, Purchase order number, and Country of origin. 7. Keywords 7. alloy steel; bolts; carbon steel; metric; screws; steel; structural; weathering steel PPENDIXES (Nonmandatory Information) X. CONVERSION GUIDNCE X. For guidance purposes only, to assist designers and purchasers in the selection of a property class, the following conversion guidance is provided: X.. Class 4.6 mechanical properties are approximately equivalent to those of Specification 307, Grade. X.. Class 8.8 mechanical properties are approximately equivalent to those of Specification 449, and Specification 35, Types and. X..3 Class mechanical properties are approximately equivalent to those of Specification 35, Type 3. X..4 Class 9.8 mechanical properties are approximately 9 % higher than those of Specification 449. X..5 Class 0.9 mechanical properties are approximately equivalent to those of Specification 354, Grade BD and Specification 490, Types and. X..6 Class mechanical properties are approximately equivalent to those of Specification 490, Type 3. X..7 Class.9 mechanical properties are approximately equal to those of Specification 574. X. Class 9.8 is applicable to fasteners of noal thread diameters M6 and smaller; Class 8.8 is applicable to fasteners larger than M6, except for Specification 35M bolts where M6 and larger bolt diameters are Class

9 X. SIGNIFICNCE OF PROPERTY CLSS DESIGNTION X. Property classes are designated by numbers where increasing numbers generally represent increasing tensile strengths. The designation symbol has the following significance: X.. The one or two numerals preceding the first decimal point approximates 00 of the imum tensile strength in MPa. X.. The numeral following the first decimal point approximates 0 of the ratio, expressed as a percentage, between imum yield stress and imum tensile strength. X..3 The numeral 3, following the second decimal point, is an indicator that the material has atmospheric corrosion resistance and weathering characteristics comparable to steels covered in Specification 588/ 588M. SUMMRY OF CHNGES Committee F6 has identified the location of selected changes to this standard since the last issue, F 568M 0, that may impact the use of this standard. (pproved ug., 004.) () Revised Section, Responsibility. () dded Section 7, Dimensions. STM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that deteration of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to STM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the STM Committee on Standards, at the address shown below. This standard is copyrighted by STM International, 00 Barr Harbor Drive, PO Box C700, West Conshohocken, P , United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting STM at the above address or at (phone), (fax), or service@astm.org ( ); or through the STM website ( 9