ASTM B91-97(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: B 91 – 97 (Reapproved 2004)
Standard Specification for
Magnesium-Alloy Forgings
ThisstandardisissuedunderthefixeddesignationB 91;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
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.
1. Scope 3. Terminology
1.1 This specification covers magnesium alloy forgings 3.1 Definitions:
designated as shown in Table 1. 3.1.1 forging—a metal part worked to a predetermined
1.2 The values stated in inch-pound units are the standard. shape by one or more such processes as hammering, upsetting,
TheSIvaluesinparenthesesareprovidedforinformationonly. pressing, or rolling.
3.1.2 die forging—a forging formed to the required shape
2. Referenced Documents
and size by working in impression dies.
2.1 The following documents of the issue in effect on date 3.1.3 hammer forging—a forging produced by repeated
of material purchase form a part of this specification to the
blows in a forging hammer.
extent referenced herein: 3.1.4 hand forging—a forging worked between flat or sim-
2.2 ASTM Standards:
ply shaped dies by repeated strokes or blows and manipulation
B 275 Practice for Codification of Certain Nonferrous Met- of the piece.
als and Alloys, Cast and Wrought
4. Ordering Information
B 557 Test Methods of Tension Testing Wrought and Cast
Aluminum- and Magnesium-Alloy Products 4.1 Orders for forgings under this specification shall include
B 660 Practices for Packaging/Packing of Aluminum and the following information:
Magnesium Products 4.1.1 Quantity of each forging,
E 29 Practice for Using Significant Digits in Test Data to 4.1.2 Alloy (Section 6 and Table 1),
Determine Conformance with Specifications 4.1.3 Temper (Section 7 and Table 2),
E 35 Test Methods for Chemical Analysis of Magnesium 4.1.4 Drawing showing dimensions of all die forgings and
and Magnesium Alloys for all hand forgings not simple disks, rounds, squares, or
E 55 PracticeforSamplingWroughtNonferrousMetalsand rectangles (the amount of stock left for machine finish should
Alloys for Determination of Chemical Composition be indicated),
2.3 Federal Standards: 4.1.5 Surface treatment (see 9.1),
No. 123 Marking for Shipment (Civil Agencies) 4.1.6 Whether inspection is required at the manufacturer’s
No. 184 Identification Marking of Aluminum, Magnesium, works (see 10.1),
and Titanium. 4.1.7 Special inspection requirements (see 10.2),
2.4 Military Standards: 4.1.8 Whether certification is required (see 12.1), and
MIL-M-3171 MagnesiumAlloy, Processes for Pretreatment 4.1.9 Whether marking for identification is required (see
and Prevention of Corrosion on 13.1).
MIL-STD-129 Marking for Shipment and Storage
5. Quality Assurance
5.1 The manufacturer shall be responsible for the perfor-
This specification is under the jurisdiction of ASTM Committee B07 on Light
mance of all inspection and tests required by this specification,
Metals and Alloys and is the direct responsibility of Subcommittee B07.04 on
prior to shipment of the material.
Magnesium Alloy Cast and Wrought Products.
Current edition approved June 1, 2004. Published June 2004. Originally
6. Chemical Composition
approved in 1932. Last previous edition approved in 1997 as B 91 – 97.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.1 Limits—The material shall conform to the chemical
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
composition limits prescribed in Table 1. The manufacturer
Standards volume information, refer to the standard’s Document Summary page on
shalldetermineconformancebyanalyzingsamplestakenwhen
the ASTM website.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
the ingots are poured, or by analyzing samples taken from the
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B 91 – 97 (2004)
A,B
TABLE 1 Chemical Composition Limits
NOTE 1—Analysis shall regularly be made only for the elements specifically mentioned in this table. If, however, the presence of other elements is
suspectedorindicatedinamountsgreaterthanthespecifiedlimits,furtheranalysisshallbemadetodeterminethattheseelementsarenotpresentinexcess
of the specified limits.
NOTE 2—The following applies to all specified limits in this table. For purposes of acceptance and rejection, an observed value or a calculated value
obtained from analysis should be rounded to the nearest unit in the last right-hand place of figures used in expressing the specified limit.
Composition, %
Alloy AZ31B Alloy AZ61A Alloy AZ80A Alloy ZK60A
Element (UNS No. (UNS No. (UNS No. (UNS No.
M11311) M11610) M11800) M16600)
Magnesium remainder remainder remainder remainder
Aluminum 2.5–3.5 5.8–7.2 7.8–9.2 .
Manganese 0.20–1.0 0.15–0.5 0.12–0.5 .
Zinc 0.6–1.4 0.40–1.5 0.20–0.8 4.8–6.2
Thorium . . . .
Zirconium, min . . 0.45
Silicon 0.10 0.10 0.10 .
Copper 0.05 0.05 0.05 .
Nickel 0.005 0.005 0.005 .
Iron 0.005 0.005 0.005 .
Calcium 0.04 . . .
C
Other impurities 0.30 0.30 0.30 0.30
A
Limits are in weight percent maximum unless shown as a range or stated otherwise.
B
These alloy designations were established in accordance with Practice B 275.
C
Includes listed elements for which no specific limit is shown.
TABLE 2 Tensile Requirements
6.3 Methods of Sampling—Samples for determination of
chemical composition shall be taken in accordance with one of
NOTE 1—For purposes of determining conformance with this specifi-
the following methods:
cation, each value for tensile strength and yield strength shall be rounded
to the nearest 0.1 ksi (0.7 MPa) and each value for elongation shall be
6.3.1 Samples for chemical analysis shall be taken from the
rounded to the nearest 0.5 %, both in accordance with the rounding
material by drilling, sawing, milling, turning, or clipping a
method of Practice E 29.
representative piece or pieces to obtain a weight of prepared
Yield Elongation
sample not less than 75 g. Sampling shall be in accordance
Tensile
A
Strength (0.2 in2in.
Alloy and Strength,
with Practice E 55.
% offset), (51 mm), or
Temper min, ksi
min, ksi 4 3 dia,
6.3.2 Samples for spectrochemical or other methods of
(MPa)
(MPa) min, %
analysis shall be taken by methods suitable for the form of
AZ31B–F 34.0 (234) 19.0 (131) 6
material being analyzed and the type of analytical method
AZ61A–F 38.0 (262) 22.0 (152) 6
used.
AZ80A–F 42.0 (290) 26.0 (179) 5
AZ80A–T5 42.0 (290) 28.0 (193) 2
6.4 Methods of Chemical Analysis—Anysuitablemethodof
ZK60A–T5 die 42.0 (290) 26.0 (179) 7
chemical analysis may be used. In case of dispute, the analysis
B
forgings
ZK60A–T6 die 43.0 (296) 32.0 (221) 4 shall be made by methods given in Test Methods E 35 or any
B
forgings
other standard methods of analysis approved by ASTM unless
A
See X1.1.6.
some other method is agreed upon.
B
Applicable only to die forgings not more than 3 in. (76 mm) in thickness. The
tensile requirements for hand forgings will be lower and as agreed upon by the
7. Tensile Properties
purchaser and manufacturer.
7.1 Limits—The forgings shall conform to the tensile prop-
erties prescribed in Table 2.
finished or semi-finished product. If the manufacturer has
7.2 Number of Specimens—One tension test specimen shall
determined the chemical composition during the course of
be taken to represent each 1000 lb (455 kg) or fraction thereof
manufacture,heshallnotberequiredtosampleandanalyzethe
of each part number in the shipment or inspection lot.
finished product.
7.2.1 When specified, a grain flow pattern and tensile-
6.2 Number of Samples—The number of samples taken for
property survey shall be made on a forging representative of
determination of chemical composition shall be as follows:
the first production parts (see 7.3.1). It shall be repeated after
6.2.1 When samples are taken at the time the ingots are
any major change in forging technique.
poured, at least one sample shall be taken for each group of
7.3 Test Specimens—Tension test specimens shall be taken
ingots poured simultaneously from the same source of molten
from a forging or from a separately forged coupon made from
metal.
material representative of the forgings, in such a manner that
6.2.2 When samples are taken from the finished or semi- the longitudinal axis of the specimen is parallel to the direction
finished product, a sample shall be taken to represent each of maximum flow of the metal in the forging. The specimens
2000 lb (905 kg), or fraction thereof, in the shipment, except shall be machined to the form and dimensions shown in Fig. 8
that not more than one sample shall be required per piece. of Test Methods B 557 or in the case o
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