The design and fabrication of the product to be galvanized are the responsibilities of the designer and the fabricator. Practice ASTM A provides guidance on safeguarding against warpage and distortion for optimum hot-dip galvanizing and shall be complied with in both design and fabrication. Steel invariably contains internal stresses induced at the mill from rolling operations used to bring structures, plate, and sheet to the final thickness. Oftentimes sheet or plate can be returned to a flattened state using a jig or by weighing the product down on a flat surface during the cool-down. After galvanizing, these products should be air cooled instead of quenched to minimize induced stress from the cooling cycle.
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ASTM C ASTM D a. ASTM A ASTM A ASTM A 3 8 4 76 4 Designation: A - 76 Reapproved Standard Practice for Safeguarding Against Warpage and Distortion During Hot-Dip Galvanizing of Steel Assemblies' This standard is issued under the fixed designation A ; the number immediately foliowing 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. Scope 1. Referenced Document 2. Factors in Warpage and Distortion 3. In nearly every case, regardless of size, channels require straightening after galvanizing.
This is not true of an I-beam, pipe, H-column, or any other section that is symmetrical about both its major axes. Channels and other nonsymmetrical sections should be avoided for the framework of a sheet metal assembly that is to be hot-dip galvanized whenever it is possible to use symmetrical shapes or sections.
In the case of sheet metal, the product which has a right-angle bend in the sheet metal itself will remain flatter and be freer from distortion if the radius of the bend is as large as practicable.
Suggested Corrections for Panel Fabrication 4. Current edition approved Oct. Published January Originally published as A - 55 T. Last previous edition A - Clamps may be applied to prevent shifting or movement during the welding operation.
In welding any intermediate lengths along one side of a common member, care should be taken to prevent warpage of the common member due to the application of high heat on the same side at various intervals along its length.
This will prevent the rusting of the surfaces which are so connected that molten zinc cannot circulate through the crevices to galvanize the contacting surfaces. I the f frame has to be dipped one half at a time, it will be better to have the sheets galvanized, rolled flat after galvanizing, and assembled to the galvanized frame by the use of aluminum alloy or galvanized rivets.
These rivets can be countersunk or flat head if the protruding head of the ordinary button or round head rivet is objectionable. If the angie steel frame and sheets are punched prior to galvanizing the recommended procedure , the use of drift pins to bring the holes into alignment should be avoided as far as possible at the time the sheets and frame are assembled. Embrittlement 5. Necessary precautions to fabricate properly and prepare the material for galvanizing to prevent embrittlement are described in Practice A It is recommended that welding procedures be carried out in conformancewith the pertinent specificationsof the American Welding Society.
Thls stendard Is subject to revision at any tlme by the responsible technical commHtee and must be reviewed every five years and H not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters.
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ASTM A384/A384M - 07(2019)
Historical Version s - view previous versions of standard. More A This specification deals with safeguarding against warpage and distortion during hot-dip galvanizing of steel assemblies. Common distorted and warped members of assemblies are sheets or plates assembled by welding or riveting.
ASTM A384 Recommendations