This standard is issued under the fixed designation A/AM; the number 1 This practice is under the jurisdiction of ASTM Committee A05 on Metallic-. In all cases only the current version of the standard as published by ASTM is to be considered the official document. Designation: A – 76 (Reapproved ) . ASTM A – A M – 02 – Download as PDF File .pdf), Text File .txt) or read online.
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Thls stendard Is subject to revision at sstm tlme by the responsible technical commHtee and must be reviewed every five years and Axtm not revised, either reapproved or withdrawn. The following can cause warpage and distortion: 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.
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. Originally published as A – 55 T. Therefore, steel thicknesses should vary as little as possible throughout the assembly. Link to Active This link will always route to the current Active version of the standard.
Wherever possible, galvanize thick and thin portions separately and join them after galvanizing. 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.
ASTM A _图文_百度文库
Suggested Corrections for Panel Fabrication 4. Referenced Documents purchase separately The documents listed below are referenced within ast subject standard but are not provided as part of the standard.
When two steels of different thicknesses are assembled and brought up to galvanizing temperature, the thinner steel heats up and expands more quickly than the thicker steel.
A number in parentheses indicates the year of last reapproval. Additionally, the installation of diagonal members should be performed after galvanizing. Steel invariably contains internal stresses induced at the mill from rolling operations used to bring structures, plate, and sheet to the final thickness. Last previous edition A – Inch pounds and SI units are not necessarily exact equivalents.
Within the text of this specification and where appropriate, SI units are shown in parentheses.
Where welding before galvanizing cannot be avoided, the internal stresses in the connections can be minimized by avoiding joint designs or weld lengths which are a34 than statically required, and by placing welds near to and symmetrically around the neutral axis – aligning welds so that shrinkage and opposing forces are balanced rather than all pulling in the same direction.
A superscript epsilon E indicates an editorial change since the last revision or reapproval. The following displays various methods to reduce or eliminate the potential asmt warpage and distortion. Welding results in significant residual stress in small areas of an assembly due to the extreme temperature differences experienced.
ASTM A Recommendations | American Galvanizer’s Association
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. Symmetrical sections such as I-beams and tubing will be less likely to distort than asymmetrical pieces camber beams, channels, tees, custom beams, girders because the thermal expansion forces above and below the natural axes balance each other.
Your comments are invited either for revision of this ashm or for additional standards and should be addressed to ASTM X384. 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.
Common distorted and warped members of assemblies are sheets or plates assembled by welding or qstm. It is recommended that welding procedures be carried out in conformancewith the pertinent specificationsof the American Welding Society. In a3884 every case, regardless of size, channels require straightening after galvanizing. Asymmetrical Design Symmetrical sections such as I-beams and tubing will be less likely to distort than asymmetrical pieces camber beams, channels, tees, custom beams, girders because the thermal expansion forces above and below the natural axes balance each other.
If the angie steel frame and sheets are punched prior to galvanizing the aatm procedurethe 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.
After galvanizing, these products should be air cooled instead of quenched to minimize induced stress from the cooling cycle. This is not true of an I-beam, pipe, H-column, or any other section that is symmetrical about both its major axes. This abstract is a brief summary of the referenced standard.
It is informational only and not an official part of the standard; the full text of the standard asm must be referred to for its use and application.
ASTM A384 Recommendations
Factors in Warpage and Distortion 3. Current edition approved Oct.
These rivets can be countersunk or flat head if the protruding head of the ordinary button or round head rivet is objectionable. Specify symmetrically rolled sections instead of angle or channel frames. Historical Version s – view previous versions of standard.
Where excessive cold working or tight bend radii cannot be avoided, the product should be stress relieved per the guidelines provided within ASTM A, Section 6. ASTM asm not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
Necessary precautions to fabricate properly and prepare the material for galvanizing to prevent embrittlement are described in Practice A Aetm corrections for panel fabrication are detailed. All efforts should be made to keep the stresses in the construction as low as possible right from the beginning to enable the steel to absorb the internal stresses completely.
Minimize Thick and Thin Material in the Same Assembly When two steels of different thicknesses are assembled and brought up to galvanizing temperature, the thinner steel heats up and expands more quickly than the thicker steel.