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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ASTM A384 Recommendations
It is recommended that welding procedures be carried out in conformancewith the pertinent specificationsof the American Welding Society. In the case of sheet metal, the product which has a right-angle bend in the a348 metal itself will remain flatter and be freer from distortion if the q384 of the bend is as large as practicable. In nearly every case, regardless of size, channels require straightening after galvanizing. Last previous edition A – 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.
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 atm immediately foliowing the designation indicates the year of original adoption or, in the case of revision, the year of last revision.
The following displays various methods to reduce or eliminate the potential for warpage and distortion. ASTM does not give any warranty express or a84 or make any representation that the contents of this abstract are accurate, complete or up to date.
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 axtm axes balance each other.
This abstract is a brief summary of the referenced standard.
A number in parentheses indicates the year of last reapproval. Furthermore, cylindrical structures are less likely to warp or distort than rectangular or elliptical ones. Optimize Welding Before Hot-Dip Galvanizing Welding results in significant residual stress in small areas of an assembly due to the extreme temperature differences experienced.
Avoid Susceptible Thin Sheet Steels Steel invariably contains internal stresses induced at the mill from rolling operations used to bring structures, plate, and sheet to the final thickness.
These rivets can be countersunk or flat head if the protruding a3384 of the ordinary button or round head rivet is objectionable. 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 greater than astmm 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.
Practice ASTM A provides guidance on safeguarding against warpage and distortion for awtm hot-dip galvanizing and shall be complied with in both design w384 fabrication. Inch pounds and SI units are not necessarily exact equivalents. After galvanizing, these products should be air cooled instead of axtm to minimize induced stress from the cooling cycle.
Within the text of this specification and where appropriate, SI units are shown in parentheses. 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.
Clamps may be applied to prevent shifting or movement during the welding operation. Common distorted and warped members of assemblies are sheets or plates assembled by welding or riveting. 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. Oftentimes sheet or plate can be returned atsm a flattened state using a jig or by weighing the product down on a flat surface during the cool-down.
Your comments are invited either for revision of this standard asrm for additional standards and should be addressed to ASTM Headquarters. This is not true of an I-beam, pipe, H-column, or any other section that is symmetrical about both its major axes. Minimize Thick and Thin Asstm 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.
Suggested Corrections for Panel Fabrication 4. Additionally, the installation of diagonal members should be performed after galvanizing. The design and fabrication of the product to be galvanized are the responsibilities of the designer and the fabricator. The overall amount of welding can be minimized by using bolted connections or performing assembly after hot-dip galvanizing. Necessary precautions to fabricate properly and prepare the material for galvanizing to prevent embrittlement are described in Practice A Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A superscript epsilon E indicates an editorial change since the last revision or reapproval. 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. The following can cause warpage and distortion: Originally published as A – 55 T.
ASTM A _图文_百度文库
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. Factors in Warpage and Distortion 3. Historical Version s 3a84 view previous versions of standard. Link to Active This link will always route to the current Active version of the standard.
It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. 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.
Welding results in significant residual stress in small areas of aatm assembly due to the extreme temperature differences experienced. If the angie steel frame and sheets are punched prior to galvanizing the recommended procedurethe use of drift pins to bring the holes into alignment should be avoided as far as w384 at the time the sheets and frame are assembled.
Specify symmetrically rolled sections instead of angle or channel frames. Wherever possible, galvanize thick and thin portions separately and join them after galvanizing.
Therefore, steel a348 should vary as little as possible throughout the assembly. 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 asmt length.
Suggested corrections for panel fabrication are detailed.
ASTM A Recommendations | American Galvanizer’s Association
This specification deals with safeguarding against warpage and distortion during hot-dip galvanizing of steel assemblies. Current edition approved Oct. Steel invariably contains internal stresses induced at the mill from rolling operations used to bring structures, plate, and sheet to the final thickness.
When two steels of different thicknesses are assembled and brought up to galvanizing astmm, the thinner steel heats up and expands more quickly than the thicker steel. 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.