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AEROSPACE AMS2681™ REV. B
MATERIAL SPECIFICATION Issued 1982-10
Revised 2000-03
Reaffirmed 2022-01
Superseding AMS2681A
Welding, Electron-Beam
RATIONALE
AMS2681B has been reaffirmed to comply with the SAE five year review policy.
1. SCOPE:
1.1 Purpose:
This specification defines the procedures and requirements for joining metals and alloys using the
electron-beam (EB) welding process.
1.2 Application:
These procedures are used typically for electron-beam welding of aerospace components in soft to
hard vacuum atmospheres, but usage is not limited to such applications. EB welding for fatigue
critical applications should be performed in accordance with AMS 2680.
2. APPLICABLE DOCUMENTS:
The issue of the following documents in effect on the date of the purchase order form a part of this
specification to the extent specified herein. The supplier may work to a subsequent revision of a
document unless a specific document issue is specified. When the referenced document has been
canceled and no superseding document has been specified, the last published issue of that document
shall apply.
2.1 SAE Publications:
Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.
AMS 2630 Ultrasonic Inspection, Product over 0.5 inch (12.7 mm) Thick
AMS 2631 Ultrasonic Inspection, Titanium and Titanium Alloy Bar and Billet
AMS 2632 Ultrasonic Inspection of Thin Materials, 0.50 inch (12.7 mm) and Thinner in Cross-
Sectional Thickness
AMS 2680 Electron Beam Welding, For Fatigue Critical Applications
ARP1317 Electron Beam Welding
ARP1333 Nondestructive Testing of Electron Beam Welded Joints in Titanium-Base Alloys
__________________________________________________________________________________________________________________________________________
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SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and
suggestions.
Copyright © 2022 SAE International
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying,
recording, or otherwise, without the prior written permission of SAE.
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Tel: +1 724-776-4970 (outside USA)
For more information on this standard, visit
Fax: 724-776-0790 https://www.sae.org/standards/content/AMS2681B/
Email: CustomerService@sae.org
SAE WEB ADDRESS: http://www.sae.org
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SAE INTERNATIONAL AMS2681™B 2 OF 10
2.2 ASTM Publications:
Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.
ASTM E 1417 Liquid Penetrant Examination
ASTM E 1444 Magnetic Particle Examination
ASTM E 1742 Radiographic Examination
2.3 U.S. Government Publications:
Available from DODSSP, Standardization Documents Order Desk, Building 4D, 700 Robbins
Avenue, Philadelphia, PA 19111-5094.
MIL-STD-1595 Qualification of Aircraft, Missile, and Aerospace Fusion Welders
2.4 AIA Publications:
Available from National Standards Association, Inc., 1250 Eye Street, Washington, D.C. 20014.
NAS 976 Electron Beam Welding Machine
3. TECHNICAL REQUIREMENTS:
3.1 Materials:
3.1.1 Parent Materials: Shall be as specified on the applicable part drawing. (See ARP1317 for
guidelines.)
3.1.2 Filler Materials: When required, filler metal shall be as specified on the part drawing.
3.1.3 Cleaning Materials: Cleaning materials, chemical solvents, and etching solutions shall be as
specified on the part drawing or in the certified welding schedule.
3.2 Equipment:
3.2.1 Electron-Beam Welding Equipment: Shall be capable of producing welds meeting the
requirements of 3.6 and 3.7. Equipment conforming to NAS 976 shall be acceptable.
3.2.2 Jigs and Fixtures: All holding fixtures shall be capable of maintaining the desired configuration and
tolerances during welding, providing back-up as required, and allowing required work space
between the work piece and the electron gun. Back-up material used to deflect or absorb residual
electron-beam energy shall be of the same alloy as the part being welded except that alternate
back-up materials may be used when approved by procedure certification as in 3.4.2. Tooling
within 6 inches (152 mm) of the weld joint shall be made from nonmagnetic materials or be
degaussed to acceptable limits (See 3.2.3).
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3.2.3 Degaussing: Ferromagnetic materials and tooling shall, prior to welding, be demagnetized to a
level established by procedure certification (3.4.2) which prevents electron-beam deflections while
welding the joint.
3.3 Preparation:
Joint and surface preparation, prior to welding, shall be as follows and shall be included as part of the
approved procedure certification:
3.3.1 Joint Preparation: Joints shall be prepared to conform to requirements specified on the part
drawing.
3.3.2 Edge Preparation: Edges shall be machined square and parallel to ensure proper fit-up. Joints
shall have no rounded-off edges, but shall be deburred after machining. (See ARP1333 for
guidelines.)
3.3.3 Pre-Weld Fit-Up: Gap shall not exceed the limits shown in Table 1, unless otherwise specified on
the certified weld schedule:
TABLE 1 - Gap Limits
Thickness Gap, max
Up to 0.009 inch (0.23 mm), incl 5% of joint thickness
Over 0.009 to 0.061 inch
(0.23 to 1.55 mm), incl 10% of joint thickness
Over 0.061 to 1.49 inch
(1.55 to 37.8 mm), incl Not to exceed 0.010 inch
(0.25 mm)
Over 1.49 inch (37.8 mm) Not to exceed 0.005 inch
(0.13 mm)
3.3.4 Weld Start and Run-Off Tabs: Tabs, when used, shall be of the same alloy as the detail parts being
welded and shall be cleaned in the same manner as the parts. Tabs shall be integral with the part,
either being machined in, or welded to, the part pieces prior to assembly.
3.3.5 Surface Preparation: Prior to welding surfaces of parts shall be prepared using a suitable cleaning
agent and method, consistent with the alloys being welded. If solvents are used on titanium alloys,
they must be nonhalogenated. Welding should commence within 40 hours after surface
preparation, unless otherwise permitted or restricted by purchaser.
3.3.5.1 After surface preparation, parts shall be handled in the joint area with clean, lint-free gloves and
shall be covered or otherwise protected to prevent contamination.
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3.3.6 Accessory Equipment Preparation: Jigs, fixtures, and measuring devices shall be free of scale,
grease, protective coatings, oxides, dust, oil, and other foreign materials detrimental to the welding
process.
3.4 Procedure:
3.4.1 Electron beam weld operators shall be certified. Unless other methods are specified by purchaser,
operators certified in accordance with MIL-STD-1595 shall be acceptable.
3.4.1.1 Personnel performing welding in accordance with this specification shall be qualified under the
cognizance and supervision of the designated welding activity and approved by the cognizant
quality control activity. Qualified personnel shall be assigned a stamp with a number or symbol
that shall be used to identify all weldments made by such personnel.
3.4.1.2 An operator undergoing qualification testing may weld a certification plate in accordance with
3.4.2 according to a pre-established schedule as part of the test.
3.4.2 Procedure Certification: Prior to production, a separate weld schedule shall be established for each
joint and alloy or alloy combination to be welded. The schedule shall be prepared for each alloy,
penetration, weld joint configuration, and for each cosmetic pass configuration, if required, showing
all applicable items listed in Table 3.
3.4.2.1 Tacking/Locking Passes: A tack weld or locking pass may be used to restrict relative motion in
the weld assembly prior to the first full penetration pass. Weld schedule certification of a tack
weld or locking pass is not required provided all of the tack welds are consumed by the
penetration pass.
3.4.2.1.1 A tacking pass, other than a full-penetration pass and made with a power density setting
substantially reduced from the certified settings, may be used over any portion of the weld joint
up to and including the full length of the weld.
3.4.2.1.2 A full-penetration tacking pass using certified parameters may be utilized but shall not exceed
10% of the weld joint length. This locking pass shall terminate in the starting or stopping tabs,
when applicable.
3.4.2.2 Cosmetic Pass: Cosmetic passes for bead appearance improvement may be applied at any time
after completion of the initial full-penetration pass. Cosmetic passes, if used, shall be certified in
accordance with 3.4.2.
3.4.3 Procedure Recertification: Recertification of weld schedules shall be required for failed test welds
and when any change is made to the following parameters:
3.4.3.1 When a change is made in parent metal composition or a change in thickness in excess of ±10%
(not applicable to cosmetic-pass-weld configuration).
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SAE INTERNATIONAL AMS2681™B 5 OF 10
3.4.3.2 When a change is made in joint design (not applicable to cosmetic-passweld configuration), but
not necessarily after changes in length of joint.
3.4.3.3 When the welding position (relationship between the gun angle and the work angle) is changed.
3.4.3.4 When a change is made in any one of the machine settings (items 1, 10, 12, 15 through 21 and
25 of Table 3).
3.4.3.4.1 The use of the beam-deflection switch, item 20 of Table 3, need not be considered when used
for the purpose of scanning or beam alignment.
3.4.3.5 When a machine other than the machine used for weld procedure certification tests is used.
3.4.4 Production Welding: Production parts shall be welded in accordance with the parameters
established in the certified weld schedule of 3.4.2.
3.4.4.1 Welding Environment: Electron-beam welding shall be performed in a vacuum at a partial
pressure not exceeding 1 x 10-3 Torr (0.133 Pa). Venting the chamber after welding shall not
occur less than two minutes after completion of welding, unless otherwise established in the
procedure certification.
3.4.5 Marking and Identification: Each weld shall be traceable to the date of welding and identifiable to
the welding operator, and shall be recorded, unless waived by purchaser.
3.4.6 Rework: A rework shall be a full or partial electron-beam penetration weld accomplished
subsequent to the full-penetration weld. Rework of imperfections, such as cosmetic passes for
correction of underfill, as well as full-penetration passes for correction of a missed joint, and other
defects may be accomplished by electron-beam welding in accordance with a certified welding
schedule. Restarting of the electron beam after an arc-out shall not be classified as a rework but
the reason, location, and method shall be recorded.
3.5 Post Treatment:
3.5.1 Finishing: Post weld machining of face or root surfaces, or both, shall be as described on the
applicable part drawing and/or the certified weld schedule. Postweld blending shall not decrease
material thickness by more than 10% of joint thickness, or more than 5% of the maximum depth of
penetration for partial penetration welds.
3.5.2 Heat Treatment: Weldments requiring heat treatment shall be processed in accordance with part
drawing requirements.
3.6 Properties:
Specimens taken from test plates, actual parts, or simulated parts produced for procedure
certification as in 3.4.2 shall conform to the following requirements:
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3.6.1 Metallurgical Examination for Soundness, and Bead Shape:
3.6.1.1 Macro-sections of the weld shall conform to the minimum requirements of the part drawing for Parallel
weld size, location, length, and configuration. Sections shall be taken transverse and parallel to
the weld direction and shall be examined at 10X magnification.
3.6.1.2 Certification test welds shall meet all requirements of the part drawing and 3.7.
3.7 Quality: Transverse
All electron-beam welds shall be subjected to visual inspection at 10X magnification and, when
specified, to radiographic inspection in accordance with ASTM E 1742 or MIL-STD-453, to ultrasonic
inspection in accordance with AMS 2630 or AMS 2632 or, for titanium and titanium alloys,
AMS 2631, to fluorescent penetrant inspection in accordance with ASTM E 1417, to magnetic
particle inspection in accordance with ASTM E 1444, or to any combination thereof, and shall
conform to the following requirements:
3.7.1 Color: The weld bead and adjacent parent metal shall have a color similar to that of the unwelded
parent metal. Discoloration due to vapor deposition occurring during welding is acceptable. Areas
that exhibit loose spatter shall be mechanically cleaned to remove loose particles. Cosmetic
passes shall not be used to change color.
3.7.1.1 In the case of titanium alloys, this color shall be a bright silver or light straw-colored in
appearance; blue-gray or gray discoloration or the presence of loose scale is not acceptable.
3.7.2 Penetration: Joints shall show evidence of complete penetration on fillet welds, tee welds, and butt
welds. Penetration for tube welds shall be as specified on the part drawing. In all other cases,
weld root reinforcement shall not exceed 1T or 0.070 inch (1.78 mm), whichever is less, except as
otherwise specified by the certified weld procedure. Weld reinforcement shall blend evenly into the
adjacent base metal with no sharp notches.
3.7.3 Incomplete Fusion: Incomplete fusion or missed joints are not acceptable. Fillet welds shall show
complete fusion at the root of the joint.
3.7.4 Cracks: Cracks are not acceptable.
3.7.5 Voids and Pores: Voids and pores open to the surface are not acceptable unless they are
subsequently to be removed by machining or blending.
3.7.6 Underfill and Concave Root Surfaces: The cumulative depths of underfill of face and root surfaces
shall not exceed the post-weld machining allowances specified on the part drawing. The allowable
underfill for each surface not machined after welding shall be 10% of the joint thickness or as
specified on the drawing.
3.7.7 Undercut and Root Notches: Where permissible, shall not exceed engineering drawing tolerances.
When not specifically noted, undercut or root notches shall not exceed 10% of material thickness
total and shall be blended to have not less than 0.06 inch (1.5 mm) root radius.
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3.7.8 Overlaps: Protrusion of weld metal beyond the toe, face, or root of the weld is not acceptable.
3.7.9 Mismatch: Shall not exceed the limits shown in Table 2.
TABLE 2 - Mismatch
Thickness Maximum Mismatch
Up to 0.250 inch 10% of joint thickness or
(6.35 mm), incl 0.010 inch (0.25 mm),
whichever is less
Over 0.250 inch (6.35 mm) 10% of joint thickness or
0.030 inch (0.76 mm),
whichever is less
3.7.10 Internal Discontinuity Limits:
3.7.10.1 Maximum Pore Diameter: The following limits apply to aluminum, titanium, iron, nickel, and
cobalt alloys for various applications:
3.7.10.1.1 0.25 Inch (6.4 mm) and Under in Nominal Parent Metal Thickness: Shall not exceed 0.33T or
0.060 inch (1.52 mm), whichever is less.
3.7.10.1.2 Over 0.25 Inch (6.4 mm) in Nominal Parent Metal Thickness: Shall not exceed 0.33T or
0.125 inch (3.18 mm), whichever is less.
3.7.10.2 Other Discontinuities: Maximum number of pores, total defect area, and defect spacing shall be
as specified by purchaser. (See ARP1317 for guidelines.)
4. QUALITY ASSURANCE PROVISIONS:
4.1 Responsibility for Inspection:
The welding processor shall be responsible for performance of all required tests. Purchaser
reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure
that welded parts conform to the requirements of this specification.
4.2 Classification of Tests:
4.2.1 Acceptance Tests: Quality (3.7) is an acceptance test and shall be performed on each weld.
4.2.2 Preproduction Tests: All technical requirements including procedure certification tests are
preproduction tests and shall be performed prior to or on the initial shipment of a welded part to a
purchaser, when a change in material and/or processing requires reapproval as in 4.4.2 and when
purchaser deems confirmatory testing to be required.
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4.3 Sampling and Testing:
Shall be in accordance with the following; a lot shall be all parts of the same alloy(s) of one
configuration processed at one time in sequence and presented for processor’s inspection at one
time:
4.3.1 For Acceptance Tests: All production weldments.
4.3.2 For Procedure Certification: Not less than three welds for procedure certification (3.4.2)
representative of each joint in the part or assembly. When test welds are made on actual
hardware, one part may be welded for procedure certification (3.4.2).
4.4 Approval:
4.4.1 The purchaser shall approve the vendor’s facilities, inspection methods, and process controls
before production parts are supplied.
4.4.2 When required by purchaser, sample welded parts and the welding procedure shall be approved
by purchaser before parts for production use are supplied. If necessary to make any significant
change in procedures or methods of inspection, the welding processor shall submit for reapproval
details of the proposed changes and, when requested sample welded joints or assemblies. A
significant change is one which, in the judgement of the cognizant engineering organization, could
affect the properties or performance of the parts.
4.5 Reports:
The processor of welded parts shall furnish with each shipment a report showing the results of tests
on each lot to determine conformance to the acceptance test requirements and stating that the parts
have been processed in accordance with the certified welding procedure by certified welding
operators. This report shall include the purchase order number, AMS 2681B, part or assembly
number, and quantity.
5. PREPARATION FOR DELIVERY:
5.1 Identification:
Welded parts shall be identified as specified on the part drawing or as agreed upon by purchaser and
vendor.
5.2 Protective Treatment:
When required, welded parts shall be given a suitable protective treatment as specified in the
process schedule or on the part drawing.
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5.3 Packaging:
5.3.1 Welded parts shall be handled and packaged in a manner to ensure that the required physical
characteristics of the parts are preserved.
5.3.2 Packages of parts shall be prepared for shipment in accordance with commercial practice and in
compliance with applicable rules and regulations pertaining to the handling, packaging, and
transportation of the parts to ensure carrier acceptance and safe delivery.
6. ACKNOWLEDGMENT:
A processor shall mention this specification number and its revision letter in all quotations and when
acknowledging purchase orders.
7. REJECTIONS:
Parts not welded in accordance with this specification, or to modifications authorized by purchaser, will
be subject to rejection.
8. NOTES:
8.1 A change bar ( l ) located in the left margin is for the convenience of the user in locating areas where
technical revisions, not editorial changes, have been made to the previous issue of this specification.
An (R) symbol to the left of the document title indicates a complete revision of the specification,
including technical revisions. Change bars and (R) are not used in original publications, nor in
specifications that contain editorial changes only.
8.2 Dimensions in inch/pound units are primary; dimensions in SI units are shown as the approximate
equivalents of the primary units and are presented only for information.
8.3 Procurement documents should specify not less than the following:
AMS 2681B
Part number to be welded
Material
Heat treatment, if required
Filler metal
Cleaning procedure
Quantity of parts to be welded
8.4 Processes meeting the requirements of this specification have been classified under Federal
Standardization Area Symbol "THJM".
PREPARED UNDER THE JURISDICTION OF AMS COMMITTEE "B"
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TABLE 3 - Minimum Parameters To Be Recorded in Welding Procedure
(When applicable)
1. Weld Machine Identification
2. Electron-Beam Certification (EBC) Number
3. Parent Metal Alloy(s)
4. Parent Metal Heat Treat Condition(s)
5. Parent Metal Thickness(es)
6. Pre-Weld Cleaning Procedure or Cleaning
Specification, or both
7. Surface Preparation at Weld Joint
8. Filler Metal Type or Specification, or both
9. Automatically Fed Filler Metal Diameter
10. Filler Wire Feed Speed (±10%)
11. Operator and ID Stamp
12. Welding Speed, inches/minute (mm/s) (±5%)
13. Welding Vacuum Pressure (Torr) (See 3.4.4.1)
14. Sketch of Set-Up Including All Angles
(±0.5 degree), Max Gap, and Max Mismatch
15. Distance of Gun to Work (±1/8 inch (±3.2 mm))
16. Beam Current (±5%)
17. High Voltage (±5%)
18. Focusing Current (±5%) or sharp focus location
19. Tacking/Locking Passes
20. Beam Deflection - On/Off
_____Type_____Amplitude_____Frequency_____
21. Cathode to Anode Spacer
22. Witnessing Inspector's Name and Stamp
23. Quality Control Certification
24. Maximum Residual Magnetism, Gauss
25. Filament Type, if applicable
26. Joint Configuration and Inspection Method
