Designation:A790/A790M–04a
Standard Specification for
Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe1
This standard is issued under thefixed designation A790/A790M;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.
A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
1.Scope*
1.1This specification2covers amless and straight-am welded ferritic/austenitic steel pipe intended for general corro-sive rvice,with particular emphasis on resistance to stress corrosion cracking.The steels are susceptible to embrittle-ment if ud for prolonged periods at elevated temperatures.
1.2Optional supplementary requirements are provided for pipe when a greater degree of testing is desired.The supplementary requirements call for additional tests to be made and,when desired,one or more of the may be specified in the order.
1.3Appendix X1of this specification lists the dimensions of welded and amless stainless steel pipe as shown in ANSI B36.19.Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification.
1.4The values stated in either inch-pound units or SI units are to be regarded parately as standard.Within the text,the SI units are shown in brackets.The values stated in each system are not exact equivalents;therefore,each system must be ud independently of the other.Combining values from the two systems may result in nonconformance with the specifi-cation.The inch-pound units shall apply unless the M desig-nation of this specification is specified in the order.
N OTE1—The dimensionless designator NPS(nominal pipe size)has been substituted in this standard for such traditional terms as nominal diameter,size,and nominal size.
2.Referenced Documents
2.1ASTM Standards:3
A370Test Methods and Definitions for Mechanical Testing of Steel Products
A941Terminology Relating to Steel,Stainless Steel,Re-lated Alloys and Feroalloys
A999/A999M Specification for General Requirements for Alloy and Stainless Steel Pipe
E213Practice for Ultrasonic Examination of Metal Pipe and Tubing
E309Practice for Eddy-Current Examination of Steel Tu-bular Products Using Magnetic Saturation
E381Method of Macroetch Testing Steel Bars,Billets, Blooms,and Forgings
E426Practice for Electromagnetic(Eddy-Current)Exami-nation of Seamless and Welded Tubular Products,Austen-itic Stainless Steel and Similar Alloys
E527Practice for Numbering Metals and Alloys(UNS) 2.2ANSI Standards:4
B1.20.1Pipe Threads,General Purpo
B36.10Welded and Seamless Wrought Steel Pipe
B36.19Stainless Steel Pipe
2.3SAE Standard:5
SAE J1086
2.4Other Standard:6
SNT-TC-1A Personal Qualification and Certification in Nondestructive Testing
2.5AWS Standard
A5.9Corrosion-Resisting Chromium and Chromium-Nickel Steel Welding Rods and Electrodes
3.Terminology
3.1Definitions—For definitions of terms ud in this speci-fication refer to Terminology A941.
4.Ordering Information
4.1Orders for material under this specification should include the following,as required,to describe the desired material adequately:
4.1.1Quantity(feet,metres,or number of lengths),
4.1.2Name of material(ferritic/austenitic steel pipe),
1This specification is under the jurisdiction of ASTM Committee A01on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.10on Stainless and Alloy Steel Tubular Products.
Current edition approved June1,2004.Published July2004.Originally approved in1981.Last previous edition approved in2004as A790/A790M–04.
2For ASME Boiler and Pressure Vesl Code applications e related Specifi-cation SA–790in Section II of that Code.
3For referenced ASTM standards,visit the ASTM website,,or contact ASTM Customer Service at For Annual Book of ASTM Standards volume information,refer to the standard’s Document Summary page on the ASTM website.
4Available from American National Standards Institute(ANSI),25W.43rd St., 4th Floor,New York,NY10036.
5Available from Society of Automotive Engineers(SAE),400Commonwealth Dr.,Warrendale,PA15096-0001.
6Available from The American Society for Nondestructive Testing(ASNT),P.O.
Box28518,1711Arlingate Ln.,Columbus,OH43228-0518.
1
*A Summary of Changes ction appears at the end of this standard. Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
Copyright ASTM International
Reproduced by IHS under licen with ASTM
Document provided by IHS Licene=Sandvik Steel/5939253100, 08/16/2004 03:24:40
MDT Questions or comments about this message: plea call the Document Policy
Group at 303-397-2295.
--``,````,,,,,,,``,`,,,`,,,,```-`-`,,`,,`,`,,`---
4.1.3Process (amless or welded),4.1.4Grade (e Table 1),
4.1.5Size (NPS designator or outside diameter and sched-ule number of average wall thickness),
4.1.6Length (specific or random)(e Section 11),
4.1.7End finish (ction on ends of Specification A 999/A 999M),
4.1.8Optional requirements (product analysis,Section 9;hydrostatic test or nondestructive electric test,Section 14),4.1.9Test report required (ction on certification of Speci-fication A 999/A 999M),
4.1.10Specification designation,and
4.1.11Special requirements and any supplementary require-ments lected.
5.General Requirements
5.1Material furnished under this specification shall con-form to the applicable requirements of the current edition of Specification A 999/A 999M unless otherwi provided herein.
6.Materials and Manufacture 6.1Manufacture :
6.1.1The pipe shall be made by the amless or an automatic welding process,with no addition of filler metal in the welding operation.
6.1.2At the manufacturer’s option,pipe may be either hot-finished or cold-finished.
6.1.3The pipe shall be pickled free of scale.When bright annealing is ud,pickling is not necessary.
6.2Discard —A sufficient discard shall be made
from each ingot to cure freedom from injurious piping and undue gregation.
6.3All pipe shall be furnished in the heat-treated condition as shown in Table 1.For amless pipe,as an alternate to final heat treatment in a continuous furnace or batch-type furnace,immediately following hot forming while the temperature of the pipes is not less than the specified minimum solution treatment temperature,pipes shall be individually quenched in water or rapidly cooled by other means,except for UNS S32950,which shall be air cooled.
7.Chemical Composition
7.1The steel shall conform to the chemical requirements as prescribed in Table 2.
8.Heat Analysis
8.1An analysis of each heat of steel shall be made by the steel manufacturer to determine the percentages of the ele-ments specified.
9.Product Analysis
9.1At the request of the purchar’s inspector,an analysis of one billet or one length of flat-rolled stock from each heat,or two pipes from each lot,shall be made by the manufacturer.A lot of pipe shall consist of the following number of lengths of the same size and wall thickness from any one heat of steel:
NPS Designator Lengths of Pipe in Lot Under 2400or fraction thereof 2to 5,incl 200or fraction thereof 6and over
100or fraction thereof
9.2The results of the analys shall be reported to the purchar or the purchar’s reprentative and shall conform to the requirements specified in Section 7.
9.3If the analysis of one of the tests specified in 8.1or 9.1does not conform to the requirements specified in Section 7,an analysis of each billet or pipe from the same heat or lot may be made,and all billets or pipe conforming to the requirements shall be accepted.
10.Tensile and Hardness Properties
10.1The material shall conform to the tensile and hardness properties prescribed in Table 3.
11.Lengths
11.1Pipe lengths shall be in accordance with the following regular practice:
11.1.1Unless otherwi agreed upon,all sizes from NPS 1⁄8to and including NPS 8are available in a length up to 24ft (e Note 2)with the permissible range of 15to 24ft (e Note 2).Short lengths are acceptable and the number and minimum length shall be agreed upon between the manufacturer and the purchar.
N OTE 2—This value applies when the inch-pound designation of this specification is the basis of purcha.When the M designation of this specification is the basis of purcha,the corresponding metric value(s)shall be agreed upon between the manufacturer and purchar.
TABLE 1Heat Treatment
UNS Designation Temperature Quench
S318031870–2010°F [1020–1100°C]Rapid cooling in air or water S322051870–2010°F [1020–1100°C]Rapid cooling in air or water S315001800–1900°F [980–1040°C]Rapid cooling in air or water S312001920–2010°F [1050–1100°C]Rapid cooling in water S325501900°F [1040°C]min
Rapid cooling in air or water S312601870–2010°F [1020–1100°C]Rapid cooling in air or water S323041700–1920°F [925–1050°C]Rapid cooling in air or water S392741920–2060°F [1025–1125°C]Rapid cooling in air or water S327501880–2060°F [1025–1125°C]Rapid cooling in air or water S327602010–2085°F [1100–1140°C]Rapid cooling in air or water S329001700–1750°F [925–955°C]Rapid cooling in air or water S329501820–1880°F [990–1025°C]Air cool
S392771975–2155°F [1080–1180°C]Rapid cooling in air or water S325201975–2050°F [1080–1120°C]Rapid cooling in air or water S329061900–1980°F [1040–1080°C]Rapid cooling in air or water S32003
1850–2050°F [1010–1120°C]
Rapid cooling in air or water
11.1.2If definite cut lengths are desired,the lengths re-quired shall be specified in the order.No pipe shall be less than the specified length and no more than 1⁄4in.[6mm]over it.11.1.3No jointers are permitted unless otherwi specified.12.Workmanship,Finish,and Appearance
12.1The finished pipes shall be reasonably straight and shall have a workmanlike finish.Imperfections may be re-moved by grinding,provided the wall thickness are not
furnace equipped with recording pyrometers and automatically controlled within a 50°F [30°C]or smaller range,the lot shall be the larger of (a)each 200ft [60m]or fraction thereof or (b)that pipe heat treated in the same batch furnace charge.
13.2.3Where the final heat treatment is obtained,consistent with the requirements of 6.3,in a batch-type heat-treatment furnace not equipped with recording pyrometers and automati-cally controlled within a 50°F [30°C]or smaller range,the term lot for mechanical tests applies to the pipe heat treated in the same batch furnace charge,provided that such pipe is of the same nominal size and wall thickness (or schedule)and is produced from the same heat of steel.
Prior to A 790/A 790M –04,the tensile strength value for UNS 32760was 109–130ksi [750–895MPa].
13.3Flattening Test—For pipe heat treated in a batch-type furnace,flattening tests shall be made on5%of the pipe from each heat-treated lot.For pipe heat treated by the continuous process,or by direct quenching after hot forming,this test shall be made on a sufficient number of pipes to constitute5%of the lot,but in no ca less than two lengths of pipe.
13.3.1For welded pipe with a diameter equal to or exceed-ing NPS10,a transver guided face bend test of the weld may be conducted instead of aflattening test in accordance with the method outlined
in the steel tubular product supplement of Test Methods and Definitions A370.The ductility of the weld shall be considered acceptable when there is no evidence of cracks in the weld or between the weld and the ba metal after bending.Test specimens from5%of the lot shall be taken from the pipes or test plates of the same material as the pipe, the test plates being attached to the end of the cylinder and welded as a prolongation of the pipe longitudinal am. 13.4Hardness Test—Brinell or Rockwell hardness tests shall be made on specimens from two pipes from each lot(e
13.2).
14.Hydrostatic or Nondestructive Electric Test
14.1Each pipe shall be subjected to the nondestructive electric test or the hydrostatic test.The type of test to be ud shall be at the option of the manufacturer,unless otherwi specified in the purcha order.
14.2The hydrostatic test shall be in accordance with Speci-fication A999/A999M,except that the value for S to be ud in the calculation of the hydrostatic test pressure shall be equal to50%of the specified minimum yield strength of the pipe.
14.3Nondestructive Electric Test:
Nondestructive electric tests shall be in accordance with Practices E213or E309.
14.3.1As an alternative to the hydrostatic test,and when specified by the purchar,each pipe shall be examined with a nondestructive test in accordance with Practices E213or E309.Unless specifically called out by the purchar,the lection of the nondestructive electric test will be at the option of the manufacturer.The range of pipe sizes that may be examined by each method shall be subject to the limitations in the scope of the respective practices.
14.3.1.1The following information is for the benefit of the ur of this specification:
14.3.1.2The reference standards defined in14.3.1.3-14.3.1.5are convenient standards for calibration of nondestruc-tive testing equipment.The dimensions of the standards should not be construed as the minimum size imperfection detectable by such equipment.
14.3.1.3The ultrasonic testing(UT)can be performed to detect both longitudinally and circumferentially oriented de-fects.It should be recognized that different techniques should be employed to detect differently oriented imperfections.The examination may not detect short,deep,defects.
14.3.1.4The eddy-current testing(ET)referenced in this specification(e Practice E426)has the capability of detect-ing significant discontinuities,especially the short abrupt type.
14.3.1.5A purchar interested in ascertaining the nature (type,size,location,and orientation)of discontinuities that can be detected in the specific application of the
examinations should discuss this with the manufacturer of the tubular product.
14.4Time of Examination—Nondestructive testing for specification acceptance shall be performed after all mechani-cal processing,heat treatments,and straightening operations. This requirement does not preclude additional testing at earlier stages in the processing.
14.5Surface Condition:
14.5.1All surfaces shall be free of scale,dirt,grea,paint, or other foreign material that could interfer
e with interpretation of test results.The methods ud for cleaning and preparing the surfaces for examination shall not be detrimental to the ba metal or the surfacefinish.
14.5.2Excessive surface roughness or deep scratches can produce signals that interfere with the test.
14.6Extent of Examination:
14.6.1The relative motion of the pipe and the transducer(s), coil(s),or nsor(s)shall be such that the entire pipe surface is scanned,except as in14.6.2.
14.6.2The existence of end effects is recognized and the extent of such effects shall be determined by the manufacturer and,if requested,shall be reported to the purchar.Other nondestructive tests may be applied to the end areas,subject to agreement between the purchar and the manufacturer. 14.7Operator Qualifications—The test unit operator shall be certified in accordance with SNT-TC-1A,or an equivalent recognized and documented standard.
14.8Test Conditions:
14.8.1For eddy-current testing,the excitation coil fre-quency shall be chon to ensure adequate pen
etration yet provide good signal-to-noi ratio.
14.8.2The maximum eddy-current coil frequency ud shall be as follows:
On specified walls up to0.050in.—100KHz max
On specified walls up to0.150in.—50KHz max
On specified walls over0.150in.—10KHz max
14.8.3Ultrasonic—For examination by the ultrasonic method,the minimum nominal transducer frequency shall be 2.00MHz and the maximum nominal transducer size shall be 1.5in.If the equipment contains a reject noticefilter tting, this shall remain off during calibration and testing unless linearity can be demonstrated at that tting.
14.9Reference Standards—Reference standards of conve-nient length shall be prepared from a length of pipe of the same grade,size(NPS,or outside diameter and schedule or wall thickness),surfacefinish and heat treatment condition as the pipe to be examined.
14.9.1For Ultrasonic Testing,the reference ID and OD notches shall be any one of the three common
notch shapes shown in Practice E213,at the option of the manufacturer.The depth of each notch shall not exceed121⁄2%of the specified nominal wall thickness of the pipe or0.004in.,whichever is greater.The width of the notch shall not exceed twice the depth.Notches shall be placed on both the OD and ID surfaces.
14.9.2For Eddy-Current Testing,the reference standard shall contain,at the option of the manufacturer,any one of the following discontinuities:
14.9.2.1Drilled Hole—The reference standard shall con-tain three or more holes equally spaced circumferentially around the pipe and longitudinally parated by a sufficient distance to allow distinct identification of the signal from each hole.The holes shall be drilled radially and completely through the pipe wall,with care being taken to avoid distortion of the pipe while drilling.One hole shall be drilled in the weld,if visible.Alternately,the producer of welded pipe may choo to drill one hole in the weld and run the calibration standard through the test coils three times with the weld turned at120°on each pass.The hole diameter shall vary with NPS as follows:
NPS Designator Hole Diameter
0.039in.(1mm)
above1⁄2to11⁄40.055in.(1.4mm)
above11⁄4to20.071in.(1.8mm)
above2to50.087in.(2.2mm)
above50.106in.(2.7mm)
14.9.2.2Transver Tangential Notch—Using a round tool orfile with a1⁄4-in.(6.4-mm)diameter,a notch shall befiled or milled tangential to the surface and transver to the longitu-dinal axis of the pipe.Said notch shall have a depth not exceeding121⁄2%of the specified nominal wall thickness of the pipe or0.004in.(0.102mm),whichever is greater.
14.9.2.3Longitudinal Notch—A less in width shall be machined in a radial plane parallel to the tube axis on the outside surface of the pipe to have a depth not exceeding121⁄2%of the specified wall thickness of the pipe or0.004in.,whichever is greater.The length of the notch shall be compatible with the testing method.
More or smaller reference discontinuities,or both,may be ud by agreement between the purchar and the manufac-turer.
14.10Standardization Procedure:
14.10.1The test apparatus shall be standardized at the beginning and end of each ries of pipes of the same size (NPS or diameter and schedule or wall thickness,grade,and heat treatment condition),and at intervals not exceeding4h. More frequent standardization may be performed at the manu-facturer’s option or may be required upon agreement between the purchar and the manufacturer.
14.10.2The test apparatus shall also be standardized after any change in test system ttings,change of operator,equip-ment repair,or interruption due to power loss,process shut-down,or when a problem is suspected.
14.10.3The reference standard shall be pasd through the test apparatus at the same speed and test system ttings as the pipe to be tested.
14.10.4The signal-to-noi ratio for the reference standard shall be21⁄2to1or greater.Extraneous signals caud by identifiable caus such as dings,scratches,dents,straightener marks,and so forth shall not be considered noi.The rejection amplitude shall be adjusted to be at least50%of full scale of the readout display.
14.10.5If upon any standardization,the rejection amplitude has decread by29%(3dB)of peak height from the last standardization,the pipe since the last calibration shall be rejected.The test system ttings may be changed or the transducer(s),coil(s),or nsor(s)adjusted and the unit restan-dardized.But all pipe tested since the last acceptable
standard-ization must be retested for acceptance.
14.11Evaluation of Imperfections:
14.11.1Pipes producing a signal equal to or greater than the lowest signal produced by the reference standard(s)shall be identified and parated from the acceptable pipes.The area producing the signal may be reexamined.
14.11.2Such pipes shall be rejected if the test signal was produced by imperfections that cannot be identified or was produced by cracks or crack-like imperfections.The pipes may be repaired per Se
ctions12and13.To be accepted,a repaired pipe must pass the same non-destructive test by which it was rejected,and it must meet the minimum wall thickness requirements of this specification.
14.11.3If the test signals were produced by visual imper-fections such as:(1)scratches,(2)surface roughness,(3)dings, (4)straightener marks,(5)cutting chips,(6)steel die stamps, (7)stop marks,or(8)pipe reducer ripple.The pipe may be accepted bad on visual examination,provided the imperfec-tion is less than0.004in.(0.1mm)or121⁄2%of the specified wall thickness(whichever is greater).
14.11.4Rejected pipe may be reconditioned and retested providing the wall thickness is not decread to less than that required by this or the product specification.The outside diameter at the point of grinding may be reduced by the amount so removed.To be accepted,retested pipe shall meet the test requirement.
14.11.5If the imperfection is explored to the extent that it can be identified as non-rejectable,the pipe may be accepted without further test providing the imperfection does not en-croach on the minimum wall thickness.
15.Repair by Welding
15.1For welded pipe of size NPS6or larger with a specified wall thickness of0.188in.[4.8mm]or more,weld repairs made with the addition of compatiblefiller metal may be made to the weld am with the same procedures specified for plate defects in the ction on Repair by Welding of Specification A999/A999M.
15.2Weld repairs of the weld am shall not exceed20%of the am length.
15.3Except as allowed by15.3.1,weld repairs shall be made only with the gas tungsten-arc welding process using the same classification of barefilter rod qualified to the most current AWS Specification A5.9as the grade of pipe being repaired as given in Table4.
15.3.1Subject to approval by the purchar,it shall be permissible for weld repairs to be made with the gas tungsten-arc welding process using afiller metal more highly alloyed than the ba metal,if needed for corrosion resistance or other properties.
Pipe Filler Metal
UNS Designation AWS A5.9Class UNS Designation S31803ER2209S39209
S32205ER2209S39209
S31200ER2553S39553
