1、Designation: A 278/A 278M 01 (Reapproved 2006)Standard Specification forGray Iron Castings for Pressure-Containing Parts forTemperatures Up to 650F (350C)1This standard is issued under the fixed designation A 278/A 278M; the number immediately following the designation indicates the yearof original
2、adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A 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 Defens
3、e.1. Scope1.1 This specification2covers gray iron for castings suitablefor pressure-containing parts for use at temperatures up to650F (350C).1.2 Classes of Iron:1.2.1 Castings of all classes are suitable for use up to 450F(230C). For temperatures above 450F and up to 650F, onlyClass 40, 45, 50, 55,
4、 and 60 castings are suitable.1.2.2 Castings of all classes are suitable for use up to 230C.For temperatures above 230C and up to 350C, only Class275, 300, 325, 350, 380, and 415 castings are suitable.2. Referenced Documents2.1 ASTM Standards:3A 644 Terminology Relating to Iron CastingsE8 Test Metho
5、ds for Tension Testing of Metallic Materials3. Terminology3.1 Definitions of many terms common to gray iron castingsmay be found in Terminology A 644.4. Classification4.1 Classification by tensile strength.4.1.1 Castings ordered to this specification are classifiedbased upon the minimum tensile stre
6、ngth of the iron in ksi, inEnglish units. Class 25 has a minimum specified tensilestrength of 25 ksi.4.1.2 Castings ordered to this specification are classifiedbased upon the minimum tensile strength of the iron in MPa, inMetric units. Class 150 has a minimum specified tensilestrength of 150 MPa.5.
7、Ordering Information5.1 Orders for material in this specification should includethe following information:5.1.1 ASTM designation and year date,5.1.2 Class of iron required and service temperature,5.1.3 Quantity,5.1.4 Heat Treatment:5.1.4.1 Whether or not heat treatment is required for Class40, 45, 5
8、0, 55, and 60 castings to be used at temperatures at450F or less (see 6.2),5.1.4.2 Whether or not heat treatment is required for Class275, 300, 325, 350, 380, and 415 castings to be used attemperatures at 230C or less (see 6.2),5.1.5 The size of separately cast test bar to be poured (seeSection 9 an
9、d Table 1),5.1.6 The size of test specimen to be machined from testbarsCorS,and5.1.7 Special requirements.6. Materials and Manufacture6.1 Castings intended for use above 450F (230C) shall bestress-relieved by placing them in a suitable furnace at atemperature not exceeding 400F (200C) and heating th
10、emuniformly to the temperatures and for the times specified inTable 2. The heating and cooling rates shall be uniform andshall not be more than 400F/h (250C/h) for castings of 1-in.(25-mm) maximum section. For heavier sections the maximumheating and cooling rates in degrees Fahrenheit per hour shall
11、be 400 divided by the maximum section thickness.6.2 Heat Treatment and Cooling Rate:6.2.1 Castings of Class Nos. 45, 50, 55, and 60, which are tobe used at temperatures below 450F, may be heat treated inaccordance with 6.1 or they shall be cooled in the mold to500F at an average rate of not more tha
12、n 100F/h for castingsup to 1 in. in section. For heavier sections the maximumcooling rate in degrees Fahrenheit per hour shall be 100divided by the maximum section thickness.6.2.2 Castings of Class Nos. 275, 300, 325, 350, 380, and415, which are to be used at temperatures below 230C, may beheat trea
13、ted in accordance with 6.1 or they shall be cooled inthe mold to 250C at an average rate of not more than 50C/h1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of SubcommitteeA04.01 on Grey and WhiteIron Castings.Current edition app
14、roved Oct. 1, 2006. Published October 2006. Originallyapproved in 1944. Last previous edition approved in 2001 as A 278/A 278M 01.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-278 in Section II of that Code.3For referenced ASTM standards, visit the ASTM website
15、, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
16、for castings up to 25-mm in section. For heavier sections themaximum cooling rate in degrees Celsius per hour shall be1250 divided by the maximum section thickness.7. Chemical Composition7.1 Carbon Equivalent:7.1.1 Class 40, 45, 50, 55, and 60 castings intended forservice above 450F (230C) shall hav
17、e a maximum carbonequivalent of 3.8 % as calculated from the equation CE = %C+ 0.3 (%Si + %P). The maximum phosphorus and sulfurcontents shall be 0.25 % and 0.12 %, respectively.7.1.2 Class 275, 300, 325, 350, 380, and 415 castingsintended for service above 230C shall have a maximumcarbon equivalent
18、 of 3.8 % as calculated from the equation CE= %C + 0.3 (%Si + %P). The maximum phosphorus and sulfurcontents shall be 0.25 % and 0.12 %, respectively.7.2 The chemical analysis for total carbon shall be made oneither chilled cast pencil-type specimens or thin wafers ap-proximately132 in. thick cut fr
19、om test coupons. Drillings shallnot be used because of attendant loss of graphite.8. Tensile Requirements8.1 Iron used in supplying castings to this specification shallconform to the tensile requirements prescribed in Table 3 andTable 4.9. Test Bars9.1 Separately cast test bars having the dimensions
20、 shown inTable 1 shall be poured from the same lot as the castingsrepresented. The size of the test bar to be poured shall beselected by the purchaser using Table 5. In the event no choiceis made, the selection will be made by the manufacturer.9.2 Separately cast test bars shall be heat treated in t
21、he samefurnace together with the castings represented.9.3 At the option of the manufacturer, test coupons may beremoved from the casting at a location agreed upon betweenthe manufacturer and purchaser.9.4 Castings weighing in excess of 2000 lb may be repre-sented either by separately cast test bars
22、(9.1) or by integrallycast test bars having a cooling rate closely approximating thatof the controlling section of the casting.9.5 For castings weighing in excess of 10 000 lb or havinga controlling section greater than 2 in., test bars may beremoved from the casting or integral projections having a
23、 crosssection no less than the controlling section. The minimumtensile strength requirement for tension tests performed oneither of these test bars shall be 80 % of the specified class.10. Molding and Pouring Test Bars10.1 The test bars shall be cast in dried siliceous sand moldsmaintained at approx
24、imately room temperature. A suitabledesign for a mold is shown in Fig. 1.11. Workmanship, Finish, and Appearance11.1 All castings shall be made in a workmanlike mannerand shall conform to the dimensions on drawings furnished bythe purchaser. If the pattern is supplied by the purchaserwithout drawing
25、s, the dimensions of the casting shall be aspredicted by the pattern.TABLE 1 Diameters and Lengths of Cast Test BarsTestBarAs-Cast Diameter, in. (mm) Length, in. (mm)Minimum(Bottom)Maximum(Top)Minimum(Specified)Maximum(Recommended)A 0.88 (23) 0.85 (22) 0.96 (25) 5.0 (125) 6.0 (1.50)B 1.20 (33) 1.14
26、(32) 1.32 (36) 7.0 (150) 9.0 (230)C 2.00 (54) 1.90 (53) 2.10 (58) 6.0 (175) 10.0 (255)SAAAll dimensions of Test Bar S shall be agreed upon by the manufacturer and thepurchaser.TABLE 2 Stress Relieving RequirementsClass Metal Temperature, F(C)Holding Time, hA40, 45, 50, 55, 60 1050 to 1200 2 12(275,
27、300, 325, 350,380, 415)(565 to 650) (2 min)B(12 max)BAIn no case shall the holding time be less than 1 h/in. of maximum metalsection, or in excess of 12 h max, dependent upon which governs.BIn no case shall the holding time be less than1hforevery 25-mm metalsection, or in excess of 12 h max, dependi
28、ng upon which governs.TABLE 3 Tensile RequirementsClass Tensile Strength,min, ksiNo. 20 20No. 25 25No. 30 30No. 35 35No. 40 40No. 45 45No. 50 50No. 55 55No. 60 60TABLE 4 Tensile Requirements (SI)Class Tensile Strength,min, MPaNo. 150 150No. 175 175No. 200 200No. 225 225No. 250 250No. 275 275No. 300
29、300No. 325 325No. 350 350No. 380 380No. 415 415TABLE 5 Separately Cast Test Bars for Use When a SpecificCorrelation Has Not Been Established Between the Test Bar andthe CastingThickness of the Wall of the ControllingSection of the Casting, in. (mm)Test BarUnder 0.25 (6) S0.25 to 0.50 (6 to 12) A0.51
30、 to 1.00 (13 to 25) B1.01 to 2 (26 to 50) COver 2 (50) SA 278/A 278M 01 (2006)211.2 The surface of the casting shall be free of adheringsand, scale, cracks, and hot tears as determined by visualexamination. Other surface discontinuities shall meet the visualacceptance standards specified in the orde
31、r.12. Sampling12.1 A lot shall consist of one of the following:12.1.1 All the metal poured from a single heating in a batchtype melting furnace,12.1.2 All the metal from two or more batch type meltingfurnaces poured into a single ladle or single casting, or12.1.3 All the metal poured from a continuo
32、us meltingfurnace for a given period of time between changes in charge,processing conditions, or aim-for chemistry or 4 h, whicheveris the shorter period.12.1.3.1 The purchaser may agree to extend the 4-h timeperiod to8hifthemanufacturer can demonstrate sufficientprocess control to warrant such an e
33、xtension.Number of test bars in a single mold-2 suggested. P2 in. (50-mm) suggestedLsee Table 1. N516 in. (8-mm) in diameter, suggestedDsee Table 1. M1.5 N, suggestedWnot less than diameter, D.FIG. 1 Suitable Design and Dimensions for Mold for Separately Cast Cylindrical Test Bars for Gray IronDimen
34、sions, in. (mm) Tension TestSpecimen ATension TestSpecimen BTension TestSpecimen CG Length of parallel, min 0.50 (13) 0.75 (20) 1.25 (32)D Diameter 0.500 6 0.010 (13 6 0.25) 0.750 6 0.015 (20 6 0.4) 1.25 6 0.025 (32 6 0.5)R Radius of fillet, min 1 (25) 1 (25) 2 (50)A Length of reduced section, min 1
35、14 (32) 112 (38) 214 (57)L Overall length, min 334 (95) 4 (100) 638 (160)C Diameter of end section, approximate78 (22) 114 (32) 178 (47)E Length of shoulder, min14 (6)14 (6)516 (8)F Diameter of shoulder58 6164 (16 6 0.5)1516 6164 (25 6 0.5) 1716 6164 (36 6 0.5)B Length of end sectionAA AAOptional to
36、 fit holders on testing machine. If threaded, root diameter shall not be less than dimension F.FIG. 2 Tension-Test SpecimensA 278/A 278M 01 (2006)313. Tension Test Specimens13.1 Tension test specimens A and B in Fig. 2 shall bemachined from test bars A and B in Table 1, respectively.13.2 The purchas
37、er shall specify whether test specimen B orC is to be machined from test bar C. If no choice is made, themanufacturer shall make the selection.13.3 The size of the test specimen to be machined from testbar S shall be as agreed upon between the manufacturer andpurchaser.14. Number of Tests and Retest
38、s14.1 One tension test shall be performed on each lot inaccordance with Test Method E8and conform to the tensilerequirements specified.14.2 If the results of a valid test fail to conform to therequirements of this specification, two retests shall be made. Ifeither retest fails to meet the specificat
39、ion requirements, thecastings represented by these test specimens shall be rejected.14.3 If, after testing, a test specimen shows evidence of adefect, the results of the test may be invalidated and anothermade on a specimen from the same lot.15. Repair15.1 Any repairs performed on castings produced
40、to thisspecification shall be agreed upon between the manufacturerand purchaser.16. Certification16.1 When requested by the purchaser, the manufacturershall furnish his certification stating that the material wasmanufactured, sampled, tested, and inspected in accordancewith this specification includ
41、ing the year date. The certificationshall also include the results of all tests performed.16.2 A signature is not required on the certification. How-ever, the document shall clearly identify the organizationsubmitting the certification and the authorized agent of themanufacturer who certified the te
42、st results. Notwithstandingthe absence of a signature, the organization submitting thecertification is responsible for its content.17. Inspection17.1 All tests and inspections required by this specificationshall be performed by the manufacturer or other reliablesources whose services have been contr
43、acted for by themanufacturer. Complete records of all tests and inspectionsshall be maintained by the manufacturer and shall be availablefor review by the purchaser.18. Rejection and Rehearing18.1 Castings which fail to conform to the requirementsspecified when inspected or tested by the purchaser o
44、r his agentmay be rejected. Rejection shall be reported to the manufac-turer or supplier promptly and in writing. In case of dissatis-faction with the test results, the manufacturer or supplier maymake claim for a rehearing.19. Product Marking19.1 Castings shall have the name of the manufacturer, or
45、his recognized trademark, and the class of iron to which itconforms, cast or indelibly stamped on a surface indicated bythe purchaser or in such a position as not to injure theusefulness of the casting.20. Keywords20.1 elevated temperature service; gray iron castings; pres-sure containing partsASTM
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49、 Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A 278/A 278M 01 (2006)4
