Standard Specification for Carbon and Alloy Steel Nuts for ...

1 Designation: A 194/A 194M 05aEndorsed byManufacturers Standardization Societyof the Valve and Fittings IndustryUsed in USNRC-RDT StandardsStandard Specification forCarbon and Alloy Steel Nuts for Bolts for High Pressure orHigh Temperature Service, or Both1 This Standard is issued under the fixed designation A 194/A 194M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last superscript epsilon (e) indicates an editorial change since the last revision or Standard has been approved for use by agencies of the Department of Scope* This specification2covers a variety of Carbon , Alloy , andmartensitic stainless Steel nuts in the size range1 4through 4in. and metric M6 through M100 nominal.

2 It also coversaustenitic stainless Steel nuts in the size range1 4in. and M6nominal and above. These nuts are intended for high-pressureor high-temperature service, or both. Grade substitutions with-out the purchaser s permission are not Bars from which the nuts are made shall be material may be further processed by centerless grindingor by cold drawing. Austenitic stainless Steel may be solutionannealed or annealed and strain-hardened. When annealed andstrain hardened austenitic stainless Steel is ordered in accor-dance with Supplementary Requirement S1, the purchasershould take special care to ensure , SupplementaryRequirement S1, andAppendix X1are thoroughly Supplementary requirements (S1 through S6) of anoptional nature are provided. These shall apply only whenspecified in the inquiry, contract, and This specification is expressed in both inch-pound unitsand in SI units.

3 However, unless the order specifies theapplicable M specification designation (SI units), the mate-rial shall be furnished to inch-pound The values stated in either inch-pound units or SI unitsare to be regarded separately as Standard . Within the text, theSI units are shown in brackets. The values stated in eachsystem are not exact equivalents; therefore, each system mustbe used independently of the other. Combining values from thetwo systems may result in nonconformance with the Referenced standards :3A 153/A 153 MSpecification for Zinc Coating (Hot-Dip) onIron and Steel HardwareA 276 Specification for Stainless Steel Bars and ShapesA 320/A 320 MSpecification for Alloy - Steel Bolting Ma-terials for Low-Temperature ServiceA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 962/A 962 MSpecification for Common Requirementsfor Steel Fasteners or Fastener Materials, or Both, Intendedfor Use at Any Temperature from Cryogenic to the CreepRangeB 633 Specification for Electrodeposited Coatings of Zincon Iron and SteelB 695 Specification for Coatings of Zinc MechanicallyDeposited on Iron and SteelB 696 Specification for Coatings of Cadmium MechanicallyDepositedB 766 Specification for Electrodeposited Coatings of Cad-miumE112 Test Methods for Determining Average Grain National standards .

4 4B Screw ThreadsB and Gaging for Unified Inch Screw ThreadsB Screw ThreadsB and Hex NutsB Heavy Hex Nuts3. of Terms Specific to This Grades All grades with a prefix of 8 or 9 .1 This specification is under the jurisdiction of ASTM Committee A01 on Steel ,Stainless Steel and Related alloys and is the direct responsibility of on Steel Forgings and Wrought Fittings for Piping Applications and BoltingMaterials for Piping and Special Purpose edition approved September 15, 2005. Published October 2005. Origi-nally approved in 1936. Last previous edition approved in 2005 as A 194/A 194M ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-194 in Section II of that referenced ASTM standards , visit the ASTM website, , orcontact ASTM Customer Service at ForAnnual Book of ASTMS tandardsvolume information, refer to the Standard s Document Summary page onthe ASTM from American National standards Institute, 25 W.

5 43rd St., 4thFloor, New York, NY *A Summary of Changes section appears at the end of this ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Grades Grades 1, 2, 2H, 2HM, 3, 4, 6, 6F, 7,7M, and Unless otherwise specified ( ), a lot is thequantity of nuts of a single nominal size and grade produced bythe same manufacturing When Supplementary Requirement S5 is invoked onthe purchase order, the following definitions of a lot shallapply:For Grade 8 Nuts The quantity of all the nuts of a singlenominal diameter and grade made from the same heat of steeland made by the same manufacturing All Other Grade Nuts( ) All the nutsof a single nominal diameter and grade made from the sameheat number and heat treated in the same batch if batch-typeheat treating equipment is used or heat treated in the samecontinuous run of not more than 8 h under the same conditionsif continuous-type heat treating equipment is Grade 8 Nuts Variations within the gradedesignated by a letter and differentiated by chemistry and bymanufacturing Grade 6 Nuts Variations within the gradedesignated by the letter F as differentiated by chemical addi-tions made for The dimensional relationship and geometryof the nuts as described in ANSIB Ordering The inquiry and order for material under this specifica-tion shall include the following as required to describe thematerial Specification designation, year date, and grade.

6 Issuedate and revision letter, Quantity, number of pieces, Dimensions (see Section9), Options in accordance , , , , and12, Supplementary Requirements, if Coatings are prohibited unless specified bythe purchaser. Nuts plated with cadmium or zinc shall bemarked as stated When coated nuts are ordered, thepurchaser should take special care to ensure thatAppendix X2is thoroughly understood. It is the purchaser s responsibility tospecify in the purchase order all information required by thecoating facility. Examples of such information may include,but are not limited to, the Reference to the appropriate coating specification:SpecificationsB 766,B 696,A 153/A 153M,B 695,B 633,orother specifications as agreed upon by the purchaser Requirements for coating thickness and local or batchaverage thickness measurement, or Requirements for selective plating or coating or modi-fication of dimensions to accommodate Requirements for hydrogen embrittlement See Supplementary Requirement S3 for nuts to be usedin low temperature applications (SpecificationA 320/A 320M).

7 5. Common Material and fasteners supplied to this specification shallconform to the requirements of SpecificationA 962/A requirements include test methods, finish, thread dimen-sions, marking, certification, optional supplementary require-ments, and others. Failure to comply with the requirements ofSpecificationA 962/A 962 Mconstitutes nonconformance withthis specification. In case of conflict between the requirementsof this specification and SpecificationA 962/A 962M, thisspecification shall Manufacture (Process) Stainless steels for all types of Grade 6 and 8 nuts shallbe made by one of the following Electric-furnace (with separate degassing and refiningoptional), Vacuum induction furnace, Either of the above followed by electroslag remelting,or consumable-arc The Steel producer shall exercise adequate control toeliminate excessive unhomogeneity, nonmetallics, pipe, poros-ity, and other Grades 1 and 2 nuts shall be hot or cold forged, or shallbe machined from hot-forged, hot-rolled, or cold-drawn All Grade 1 and 2 nuts made by cold forging or bymachining from cold-drawn bars shall be stress-relief annealedat a temperature of at least 1000 F [538 C].

8 Grade 1 and 2 nuts made by hot forging or bymachining from hot-forged or hot-rolled bars need not be givenany stress relief annealing Grades 2H, 2HM, 3, 4, 6, 6F, 7, 7M, and 16 nuts shallbe hot- or cold-forged or shall be machined from hot-forged,hot-rolled, or cold-drawn bars and shall be heat treated to meetthe required mechanical properties. These grades shall bereheated above the critical range of the Steel , quenched in asuitable medium, and then tempered at a temperature not lessthan the following:GradeMinimum Tempering Temperature, F[ C]2H850 [455]2HM1150 [620]31050 [565]41100 [595]6 and 6F1100 [595]71100 [595]7M1150 [620]161200 [650]Nuts machined from bar heat treated in accordance with thisspecification need not be reheat-treated. For Grade 2HM and7M nuts, a final stress relief shall be done at or above theminimum tempering temperature after all forming, machining,and tapping operations.

9 This final stress relief may be thetempering Grade 6 and 6F nuts shall be tempered for a Grades 8, 8C, 8M, 8T, 8F, 8P, 8N, 8MN, 8R, 8S, 8LN,8 MLN, 8 MLCuN, and 9C nuts shall be hot or cold forged, orshall be machined from hot-forged, hot-rolled or 194/A 194M Grades 8A, 8CA, 8MA, 8TA, 8FA, 8PA, 8NA, 8 MNA,8RA, 8SA, 8 LNA, 8 MLNA, 8 MLCuNA, and 9CA nuts shallbe hot- or cold-forged or shall be machined from hot-forged,hot-rolled, or cold-drawn bars and the nuts shall subsequentlybe carbide-solution treated by heating them for a sufficient timeat a temperature to dissolve chromium carbides followed bycooling at a rate sufficient to prevent reprecipitation of Chemical Each Alloy shall conform to the chemical compositionrequirements prescribed inTable Mechanical All nuts shall meet the hardness requirements speci-fied inTable Sample nuts of Grades 1, 2, 2H, 2HM, 3, 4, 7, 7M,and 16 which have been given the treatment described meet the minimum hardness specified inTable of Tests (Grades 1, 2, 2H, 3, 4, 7, and 16and all types of Grade 6) Tests on the number of sample nuts in accordancewith the following table shall be performed by the manufac-turer following all production heat treatments.

10 Lot SizeSamplesUp to 8001801 to 800028001 to 22 0003 Over 22 In addition, a hardness test shall be performed by themanufacturer in accordance one sample nutselected from each nominal diameter and series from eachgrade and heat number following completion of all productionheat of Tests, Grades 2HM and 7 Each nut shall be tested by Brinell or Rockwellmethods to ensure product In addition, be of Tests, All Types of Grade 8 Tests on thenumber of sample nuts in accordance beperformed by the 2 In addition to the testing required manufacturer shall also perform hardness tests on samplenuts after the following test heat treatment. After completion ofall production heat treatments heat the specimen nuts to thetemperatures indicated below for 24 h, then slow cool. Test atroom , F [ C]1850 [455]2, 2H, 2HM1000 [540]3, 4, 7, 7M1100 [590]161200 [650]ANuts intended to be coated with zinc or cadmium (marked in accordance withthe requirements ) are not subjected to the requirements (SeeAppendix X2).