1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (412) 772-8512 FAX: (412) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (412) 776-4970 FAX: (412) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1989 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001INFORMATIONREPORTJ464REAF.JAN89Issued 1940-01Reaffirmed 1989-01Supercedi
4、ng J464cMAGNESIUM ALLOYSForewordThis Document has not changed other than to put it into the new SAE Technical Standards BoardFormat.1. ScopeThis report on magnesium alloys covers those alloys which have been more commonly used in theUnited States for automotive, aircraft, and missile applications. B
5、asic information on nomenclature and temperdesignation is given. Design data and many characteristics covered by a purchase specification are notincluded.2. References2.1 Applicable PublicationsThe following publications form a part of the specification to the extent specifiedherein. Unless otherwis
6、e indicated the lastest revision of SAE publications shall apply.2.1.1 ASTM PUBLICATIONSAvailable from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM B 275 Recommended Practice for Codification of Light Metals and Alloys, Cast and WroughtASTM B 296Recommended Practice for Temper
7、Designation of Magnesium Alloys, Cast and Wrought3. Sources Of MagnesiumMagnesium is the third most abundant structural element in the earths crust, andconsidered inexhaustible. Common sources are sea water, natural brines, magnesite, and dolomite. Threemethods of extraction are used in the United S
8、tates. One method involves treating sea water with a source ofalkalinity (lime or caustic soda) to precipitate the magnesium as hydroxide, which is then mixed withhydrochloric acid to produce magnesium chloride. The magnesium chloride is reduced electrolytically toproduce magnesium metal and a mixtu
9、re of chlorine and hydrochloric acid. A second method producescoproduct magnesium metal and pure chlorine in the electrolytic cell by the reduction of anhydrousmagnesium chloride. The anhydrous cell feed results from the dehydration of natural brines. Another methodof extraction which is also used i
10、n the United States and in other countries is a thermal reduction method,generally referred to as the ferro-silicon process, employing an alloy of iron and silicon to reduce magnesiumoxide. Most of the magnesium ingot sold is of 99.80% purity. Grades of magnesium of 99.90, 99.95, and99.98% purity ar
11、e also available. The higher purity grades are used mostly in nuclear applications and forreduction purposes.COPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J464 Reaffirmed JAN89-2-4. PropertiesMagnesium is extremely light with the common alloys having a s
12、pecific gravity of about 1.8compared to 2.7 for aluminum. The heavier structural metals like iron, copper, and zinc are approximately fourtimes as heavy as magnesium. Magnesium melts at 650C (1202F). The coefficient of thermal expansionbetween 20100C (68212F) is approximately 0.0000261/C (0.0000145/
13、F) and is slightly higher than foraluminum, 0.000023/C (0.000013/F), and over twice that of steel. The thermal and electrical conductivities ofmagnesium are relatively high and some alloys approach values comparable to aluminum alloys. The modulusof elasticity is approximately 45 GPa (6 500 000 psi)
14、. The pure metal is not used for structural applications. Anumber of alloys have been developed with good strength-to-weight ratios.5. Alloying ElementsCommon alloying elements used in magnesium alloys are aluminum, manganese, rareearths, silver, thorium, zinc, and zirconium. Alloys are stronger tha
15、n the pure metal but have lower electricaland thermal conductivities. Certain of the alloys respond to heat treatment with an increase in strength andhardness. Another means used to increase the strength of magnesium is by cold work. Most commercialalloys are stable at room temperature. Certain allo
16、ying elements such as the rare earths and thorium givebetter high temperature strength than can be obtained with the more common alloying elements aluminum andzinc.6. Alloy NomenclatureA designation system for magnesium alloys used commercially and described in ASTMB 275, Recommended Practice for Co
17、dification of Light Metals and Alloys, Cast and Wrought, was adopted bySAE in 1971. The initial letter(s) represent the major alloying element(s) with the following numeral(s)representing the nominal percent by weight of each element. The final letter is assigned arbitrarily.7. Temper DesignationThe
18、 same temper designation system is used for both aluminum base and magnesiumbase alloys. It is described in detail under the aluminum alloy section of this book and in ASTM B 296,Recommended Practice for Temper Designation of Magnesium Alloys, Cast and Wrought.8. WorkingMagnesium alloys are availabl
19、e in most commercial forms such as die castings, investment, sandand permanent mold castings, extrusion, forgings, sheet, and plate. It can be formed by drawing, spinning, andpressing. The working is done best at elevated temperatures because of improved workability and freedomfrom springback. Magne
20、sium can be joined by adhesive bonding, bolting, riveting, and welding. Arc welding,using an inert gas shield, is the most commonly used method of fusion welding. Spot welding is usedextensively. Magnesium, in all its forms, can be readily machined with exceptional speed and tool life.9. Finishing A
21、nd CoatingBare magnesium is suitable for many applications. Protective finishes may berequired to prevent tarnishing or for protection from corrosion in humid industrial or marine atmospheres. It issubject to galvanic attack when coupled to most other metals, and such connections should be adequatel
22、yprotected if moisture will be present. Magnesium can be finished by plating and painting for either protection ordecoration.10. TestingMagnesium alloys are tested like other metals using standard ASTM methods. The tensile andcompressive yield strengths are defined as the stress at which the stress-
23、strain curve deviates 0.2% from theinitial modulus line.PREPARED BY THE SAE CAST ALUMINUM COMMITTEECOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling ServicesSAE J464 Reaffirmed JAN89RationaleNot applicable.Relationship of SAE Standard to ISO StandardNot applicable.Appli
24、cationThis report on magnesium alloys covers those alloys which have been more commonly used inthe United States for automotive, aircraft, and missile applications. Basic information on nomenclatureand temper designation is given. Design data and many characteristics covered by a purchasespecificati
25、on are not included.Reference SectionASTM B 275Recommended Practice for Codification of Light Metals and Alloys, Cast and WroughtASTM B 296Recommended Practice for Temper Designation of Magnesium Alloys, Cast and WroughtDeveloped by the SAE Cast Aluminum CommitteeCOPYRIGHT Society of Automotive Engineers, Inc.Licensed by Information Handling Services
