ASTM B91-97
(Specification)Standard Specification for Magnesium-Alloy Forgings
Standard Specification for Magnesium-Alloy Forgings
SCOPE
1.1 This specification covers magnesium alloy forgings designated as shown in Table 1.
1.2 The values stated in inch-pound units are the standard. The SI values in parentheses are provided for information only.
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Designation: B 91 – 97
Standard Specification for
Magnesium-Alloy Forgings
This standard is issued under the fixed designation B 91; the number immediately following the designation indicates the year of original
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 Defense.
1. Scope * 3.1.1 forging—a metal part worked to a predetermined
shape by one or more such processes as hammering, upsetting,
1.1 This specification covers magnesium alloy forgings
pressing, or rolling.
designated as shown in Table 1.
3.1.2 die forging—a forging formed to the required shape
1.2 The values stated in inch-pound units are the standard.
and size by working in impression dies.
The SI values in parentheses are provided for information only.
3.1.3 hammer forging—a forging produced by repeated
2. Referenced Documents
blows in a forging hammer.
3.1.4 hand forging—a forging worked between flat or sim-
2.1 The following documents of the issue in effect on date
ply shaped dies by repeated strokes or blows and manipulation
of material purchase form a part of this specification to the
of the piece.
extent referenced herein:
2.2 ASTM Standards:
4. Ordering Information
B 275 Practice for Codification of Certain Nonferrous Met-
2 4.1 Orders for forgings under this specification shall include
als and Alloys, Cast and Wrought
the following information:
B 557 Test Methods of Tension Testing Wrought and Cast
4.1.1 Quantity of each forging,
Aluminum- and Magnesium-Alloy Products
4.1.2 Alloy (Section 6 and Table 1),
B 660 Practices for Packaging/Packing of Aluminum and
4.1.3 Temper (Section 7 and Table 2),
Magnesium Products
4.1.4 Drawing showing dimensions of all die forgings and
E 29 Practice for Using Significant Digits in Test Data to
for all hand forgings not simple disks, rounds, squares, or
Determine Conformance with Specifications
rectangles (the amount of stock left for machine finish should
E 35 Test Methods for Chemical Analysis of Magnesium
be indicated),
and Magnesium Alloys
4.1.5 Surface treatment (see 9.1),
E 55 Practice for Sampling Wrought Nonferrous Metals and
4.1.6 Whether inspection is required at the manufacturer’s
Alloys for Determination of Chemical Composition
works (see 10.1),
2.3 Federal Standards:
4.1.7 Special inspection requirements (see 10.2),
No. 123 Marking for Shipment (Civil Agencies)
4.1.8 Whether certification is required (see 12.1), and
No. 184 Identification Marking of Aluminum, Magnesium,
4.1.9 Whether marking for identification is required (see
and Titanium.
13.1).
2.4 Military Standards:
MIL-M-3171 Magnesium Alloy, Processes for Pretreatment
5. Quality Assurance
and Prevention of Corrosion on
5 5.1 The manufacturer shall be responsible for the perfor-
MIL-STD-129 Marking for Shipment and Storage
mance of all inspection and tests required by this specification,
3. Terminology prior to shipment of the material.
3.1 Definitions:
6. Chemical Composition
6.1 Limits—The material shall conform to the chemical
This specification is under the jurisdiction of ASTM Committee B-7 on Light
composition limits prescribed in Table 1. The manufacturer
Metals and Alloys and is the direct responsibility of Subcommittee B07.04 on
shall determine conformance by analyzing samples taken when
Magnesium Alloy Cast and Wrought Products.
Current edition approved Oct. 10, 1997. Published May 1998. Originally the ingots are poured, or by analyzing samples taken from the
published as B 91 – 32 T. Last previous edition B 91 – 92.
finished or semifinished product. If the manufacturer has
Annual Book of ASTM Standards, Vol 02.02.
determined the chemical composition during the course of
Annual Book of ASTM Standards, Vol 14.02.
manufacture, he shall not be required to sample and analyze the
Annual Book of ASTM Standards, Vol 03.05.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 finished product.
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B91
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
suspected or indicated in amounts greater than the specified limits, further analysis shall be made to determine that these elements are not present in excess
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
representative piece or pieces to obtain a weight of prepared
sample not less than 75 g. Sampling shall be in accordance
NOTE 1—For purposes of determining conformance with this specifi-
with Practice E 55.
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 6.3.2 Samples for spectrochemical or other methods of
rounded to the nearest 0.5 %, both in accordance with the rounding
analysis shall be taken by methods suitable for the form of
method of Practice E 29.
material being analyzed and the type of analytical method
Yield Elongation
used.
Tensile
A
Strength (0.2 in 2 in.
Alloy and Strength,
6.4 Methods of Chemical Analysis—Any suitable method of
% offset), (51 mm), or
Temper min, ksi
chemical analysis may be used. In case of dispute, the analysis
min, ksi 4 3 dia,
(MPa)
(MPa) min, %
shall be made by methods given in Test Methods E 35 or any
AZ31B–F 34.0 (234) 19.0 (131) 6 other standard methods of analysis approved by ASTM unless
AZ61A–F 38.0 (262) 22.0 (152) 6
some other method is agreed upon.
AZ80A–F 42.0 (290) 26.0 (179) 5
AZ80A–T5 42.0 (290) 28.0 (193) 2
ZK60A-T5 die 42.0 (290) 26.0 (179) 7
7. Tensile Properties
B
forgings
7.1 Limits—The forgings shall conform to the tensile prop-
ZK60A-T6 die 43.0 (296) 32.0 (221) 4
B
forgings
erties prescribed in Table 2.
A
See X1.1.6. 7.2 Number of Specimens—One tension test specimen shall
B
Applicable only to die forgings not more than 3 in. (76 mm) in thickness. The
be taken to represent each 1000 lb (455 kg) or fraction thereof
tensile requirements for hand forgings will be lower and as agreed upon by the
of each part number in the shipment or inspection lot.
purchaser and manufacturer.
7.2.1 When specified, a grain flow pattern and tensile-
property survey shall be made on a forging representative of
6.2 Number of Samples—The number of samples taken for the first production parts (see 7.3.1). It shall be repeated after
determination of chemical composition shall be as follows: any major change in forging technique.
6.2.1 When samples are taken at the time the ingots are 7.3 Test Specimens—Tension test specimens shall be taken
poured, at least one sample shall be taken for each group of from a forging or from a separately forged coupon made from
ingots poured simultaneously from the same source of molten material representative of the forgings, in such a manner that
metal. the longitudinal axis of the specimen is parallel to the direction
6.2.2 When samples are taken from the finished or semifin- of maximum flow of the metal in the forging. The specimens
ished product, a sample shall be taken to represent each 2000 shall be machined to the form and dimensions shown in Fig. 8
lb (905 kg), or fraction thereof, in the shipment, except that not of Test Methods B 557 or in the case of thin material may be
more than one sample shall be required per piece. machined to the form and dimensions shown for the ⁄2 in.
6.3 Methods of Sampling—Samples for determination of (12.7 mm) wide sheet-type specimen in Fig. 6 of Test Methods
chemical composition shall be taken in accordance with one of B 557.
the following methods: 7.3.1 If required, a die forging representative of the first
6.3.1 Samples for chemical analysis shall be taken from the production parts s
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