Zinc Coating Thickness Requirements: ASTM A vs. F Dimension. ASTM A ASTM F Avg. Coating. Thickness of. Specimens. Tested. 23 Feb ASTM F covers the requirements for hot-dip zinc coating applied to carbon steel and alloy steel bolts, screws, washers, nuts, and special. 4 Jan ASTM A does not cover threaded bolts and fasteners. ASTM A and F are the ASTM specifications that cover the requirements for.
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Threaded fasteners are handled differently in order to remove the excess zinc from the threads and would fall under A or F Nails and rivets are not included in F The two specifications have virtually identical coating thickness requirements. A covers galvanizing on many products including fasteners, while F is specific to threaded fasteners, nuts and washers. For long pieces anchor rods or articles greater than five feet in lengthcoating thickness measurements must be taken on each end and in the middle of the article.
On the other hand, if embrittlement testing is necessary under F, it is to be conducted per ASTM F a wedge positioned and tensioned under a bolt headwhich is a different method than any of the methods described within A Paragraph 9. The type of production lot process will determine which column should be referenced for the sample size of each inspection criteria, as summarized in the table below, or per the F Sampling Plan Flow Chart.
Combining values from the two systems may result in non-conformance with the standard. These instances can include when steel has been severely work hardened or when the galvanizing bath temperature exceeds the stress relief or tempering temperatures of the fasteners.
Nails and rivets are not included in this specification.
Table 2 of F lists average coating thickness requirements for production lots, batch lots, and individual specimens. The differences in the types of lots entail different sampling plans, which specify the number of test articles for performing various test methods during inspection of the finished product. Compared to the sampling plan in A, F requires fewer samples per batch lot size, but the galvanizer is required to also conduct adhesion testing and axtm inspection for appearance on these test articles as defined by Table 1.
April 10, Authored by Bernardo A. The major differences between the two specifications, 2f329 below, include topics related to sampling protocol, coating thickness, inspection, embrittlement, and documentation.
Coating Thickness Table 2 of F lists average coating thickness requirements for production lots, batch lots, and individual specimens. Phil- The hot dip galvanizing process is f23229 or less the same within all of those standards, the difference is how they are handled.
Otherwise, a third party will be required to apply the lubricant at an additional cost. It is not a dip spin coating like hot dip galvanizing is. If you are concerned about the hardness dropping, you could look at alternatives platings that do not require heat, like mechanical galvanizing. It is important to ensure the customer specifies which type of lot is required. According to Note C of Table 1, It is only required to conduct testing on samples for coating thickness once every five batch lots.
This specification is intended to be applied to hardware items that are centrifuged or otherwise handled to remove excess zinc. One of our experienced sales reps will be happy to answer any of your questions. This specification covers the requirements for hot-dip galvanizing on iron and steel products made from rolled pressed and forged shapes, castings, plates, bars, and strips.
ASTM F The standard specification that covers the requirements for hot-dip zinc coating applied to carbon steel and alloy steel bolts, screws, washers, nuts, and special threaded fasteners applied by the hot-dip coating process. Dane- Thanks for response. ASTM A This specification covers the requirements for hot-dip galvanizing on iron and steel products made from rolled pressed and forged shapes, castings, plates, bars, and strips.
Could you please clarify? It is intended to be applicable to fasteners that are centrifuged or otherwise handled to remove excess zinc. The zinc used for the coating shall conform to the chemical composition required. It is important f2239 note the acceptance criterion in all cases is zero defects.
It also provides for minor coating repairs. It does not cover threaded fasteners that are centrifuged or otherwise handled to remove excess zinc. If your requirement is for hot dip galvanizing, electroplating would not be sufficient.
Work F2239 s – proposed revisions of this standard.
Hot-Dip Galvanizing Specifications
Because A does not require water quenching nor chemical post-treatments, communication between the customer and the galvanizer is required to determine whether the galvanizer has a quench tank and the capability to perform chemical post-treatments, or if air-cooling will be acceptable. The temperatures used in the hot-dip galvanizing process typically do not appreciably alter the mechanical properties of steel, but there are some instances when there are potential concerns.
See excerpt of Table 1 below. F239 which are subjected to severe work hardening must be stress-relieved prior to galvanizing. aastm
Hot-Dip Galvanizing Specifications – Portland Bolt
Portland Bolt performs hot dip galvanizing of threaded fasteners within our 85, square foot manufacturing facility. A touches on threaded fasteners, but is not fastener specific. A summary of the numerical differences between the two specifications related to coating thickness requirements for all materials is presented in the table: ASTM F describes two different sampling plans for batch lots and production lots. 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.
ASTM F2329 vs. ASTM A153
Contact us if you have a need for hot-dip galvanized fasteners or with any technical questions regarding hot-dip galvanizing. Vinay- ASTM A and A both say that the maximum service temperature for galvanized bolts should not exceed F unless caution is used in regard to the potential for liquid hydrogen embirittlement. Galvanizing fasteners in accordance with A, will usually meet or exceed the requirements of F, because F defers to A in many sections.
The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. The amount of additional documentation beyond ASTM A requirements will vary depending on a number of optional requirements the customer can specify under F Since threaded fasteners are spun at high speeds in a centrifuge to remove excess zinc from the threads, they would fall under the A class C specification.
ASTM A does not cover threaded bolts and fasteners.