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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Optimize Welding Before Hot-Dip Galvanizing Astmm results in significant residual stress in small areas of an assembly due to the extreme temperature differences experienced. The design and fabrication of the product to be galvanized are the responsibilities of the designer and the fabricator.
Furthermore, cylindrical structures are less likely to warp or distort than rectangular or elliptical ones. This specification deals with safeguarding against warpage and distortion during hot-dip galvanizing of steel assemblies.
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 xstm steel. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
Therefore, steel thicknesses should vary as little a348 possible throughout the assembly. Inch pounds and SI units are not necessarily exact equivalents.
ASTM A384 Recommendations
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. Common distorted and warped members of assemblies are sheets or plates assembled by welding or riveting.
Additionally, the installation of diagonal members should be performed after a84. Welding results in significant residual stress in small areas of an assembly due to the extreme temperature differences experienced. After galvanizing, these products should be air cooled instead of quenched to minimize induced stress from the cooling cycle.
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.
The overall amount of welding can be minimized by using bolted connections or performing assembly after hot-dip galvanizing.
ASTM A _图文_百度文库
Historical Version s – view ashm versions of standard. 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.
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. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Within the text of this specification and where appropriate, SI units are shown in parentheses.
The following displays various methods to reduce or eliminate the potential for warpage and distortion. Suggested corrections for panel fabrication are detailed. This abstract is a brief summary of the referenced standard.
The following can cause warpage and distortion: Specify symmetrically rolled sections instead of angle or zstm frames. All efforts should ast, 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.
Wherever possible, galvanize thick and thin portions separately and join them s384 galvanizing.
Oftentimes sheet or plate can be returned to a flattened state using a jig or by weighing the product down on a flat wstm during the cool-down. Steel invariably contains internal stresses induced at the mill from rolling operations used to bring structures, plate, and sheet to the final thickness. Link to Active This link will always route to the current Active version of the standard. Where excessive cold working or tight bend radii cannot q384 avoided, the product should be stress relieved per the guidelines provided within ASTM A, Section 6.
ASTM A Recommendations | American Galvanizer’s Association
Asymmetrical Design Symmetrical sections such as I-beams and tubing will be less likely to distort than asymmetrical pieces camber beams, channels, a3844, custom beams, girders because the thermal expansion forces above and below the natural axes balance each other.
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 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. 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.