However, the AGA does provide a compilation of specifications pertinent to galvanizing. Purchase a copy from the AGA, or contact your local galvanizer. The material categories covered in the specification include structural steel and plate, strips and bars, pipes and tubing, and wires. Fabrications can have more than one material category, such as a frame assembly. Any combination of these products can be assembled into a single fabrication and then hot-dip galvanized. It is the responsibility of the designer and fabricator to ensure the product has been properly designed and built before the hot-dip galvanizing process supporting specifications.
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ASTM A ASTM D a. ASTM D ASTM A A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.
Scope 1. Conditions of fabrication may induce a susceptibility to embrittlement in certain steels which can be accelerated by galvanizing.
Embrittlement is not a common occurrence, however, and this discussion does not imply that galvanizing increases embrittlement where good fabricating and galvanizing procedures are employed.
Where history has shown that for speci? It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Terminology 2. An embrittled product characteristically fails by fracture without appreciable deformation. Types of embrittlement usually encountered in galvanized steel are related to aging phenomena, cold working, and absorption of hydrogen.
Prepared by Subcommittee A See Proceedings, Am. Testing Mats. Current edition approved October 10, Published December Originally published as A — 32 T. Last previous edition A — 74 Reapproved Factors in Embrittlement 3. Strain-aging refers to the delayed increase in hardness and strength, and loss of ductility and impact resistance which occur in susceptible steels as a result of the strains induced by cold working.
The susceptibility to hydrogen embrittlement is in? In the case of galvanized steel, the acid pickling reaction prior to galvanizing presents a potential source of hydrogen. However, the heat of the galvanizing bath partially expels hydrogen which may have been absorbed. In practice hydrogen embrittlement of galvanized steel is usually of concern only if the steel exceeds approximately ksi MPa in ultimate tensile strength, or if it has been severely cold worked prior to pickling.
The rate at which this temperature loss of ductility occurs varies for different steels. The expected service temperature should thus be taken into account when selecting the steel. Steels 4. Cold Working and Thermal Treatment 5. These criteria generally depend on the direction of grain, strength, and type of steel. A cold bending radius of three times 33 the section thickness, or as recommended in AISC Manual of Steel Construction,2 will ordinarily ensure satisfactory properties in the?
Although sharper bending on thin sections can usually be tolerated, embrittlement may occur if cold bending is especially severe. If the design requires sharper bending than discussed herein, the bending should be done hot, or if done cold the material should be subsequently annealed or stress relieved as noted in 5. Shapes 5?
The heavier shapes 3? However, if required, proper thermal treatment shall precede galvanizing of the steel. For heavy cold deformation exempli? For less severe cold deformation typi? After cutting, the cut surface shall be ground to remove notches, grooves, and irregular surface features to leave the surface smooth. Preparation for Galvanizing 6. The likelihood of this, or of surface cracking occurring, is increased by excessive pickling temperature, prolonged pickling time, and poor inhibition of the pickling acid.
Responsibility for Avoiding Embrittlement 7. Wacker Dr. See p. The galvanizer shall employ proper pickling and galvanizing procedures. If one test specimen should be found embrittled by these tests, two additional specimens should be tested. Failure of either the second or the third specimen shall be cause for rejection of the lot see Note 1 that the samples represent. NOTE 1—A lot is a unit of production from which a sample may be taken for testing. Unless otherwise agreed upon by the manufacturer and the purchaser, or established within this speci?
For test by purchaser after delivery, the lot consists of the single order or the single delivery load, whichever is the smaller, unless the lot identity, established in accordance with the above, is maintained and clearly indicated in the shipment by the manufacturer.
In the case of previously bent articles such as reinforcing bars, the test shall be accomplished by reverse bending the previously bent section.
The galvanized article should withstand a degree of bending substantially the same as the ungalvanized article. Flaking or spalling of the galvanized coating is not to be construed as an embrittlement failure. For threaded articles, the test shall be made on the unthreaded portion. If the article withstands such a blow in the ungalvanized condition, but after galvanizing cracks under the blow, it shall be considered embrittled. A hole shall be made in the test specimen at its midlength, using the same procedure as will be employed in the fabricated material which the specimen represents, whether this be by punching, punching and reaming, or drilling.
The dimensional values, diameter, and location of hole shall be not less than those employed in the structural details. Care should be taken not to place the hole near stamped or rolled-in identi? The specimen shall then be galvanized. For determining the elongation after fracture, a 2-in. For specimens under 1? The length of the test specimen and the distance between the supports are shown in the following table: Leg of Angle, l, in. The percentage reduction of thickness shall be calculated on the basis of the original thickness of the angle and the average of the three values at a, b, and c.
The sum of the percentage of elongation plus the average percentage reduction of thickness shall not be less than Up to 4 , incl Over 4 to 6 to , incl Over 6 to 8 to , incl 18 24 36 8. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below.
Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phone , fax , or service astm.
Historical Version s - view previous versions of standard. More A This practice covers procedures that can be followed to safeguard against the possible embrittlement of steel hot-dip galvanized after fabrication, and outlines test procedures for detecting embrittlement. Conditions of fabrication may induce a susceptibility to embrittlement in certain steels that can be accelerated by galvanizing. Open-hearth, basic-oxygen, and electric-furnace steels shall be used for galvanizing.