Zinc Coating Thickness Requirements: ASTM A vs. F Dimension. ASTM A ASTM F Avg. Coating. Thickness of. Specimens. Tested. ASTM F covers the requirements for hot-dip zinc coating applied to carbon steel and alloy steel bolts, screws, washers, nuts, and special. 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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Authored by Alana Hochstein. Galvanizing fasteners in accordance with A, will usually meet or exceed the requirements of F, because F defers to A in many sections. The major differences between the two specifications, described below, include topics related to sampling protocol, coating thickness, inspection, embrittlement, and documentation. ASTM F describes two different sampling plans for batch lots and production lots.
ASTM F – Portland Bolt
Furthermore, there are two types of production lots: 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 aztm finished product.
It is important to ensure the customer specifies which type of lot is required. F defines the two different lots and their associated sampling plans as follows:. The batch lot inspection process is more similar to inspection under A than inspection of production lots, but Table 1 of F has some additional requirements to consider. See excerpt of Table 1 below. There are three columns listing the number of test articles for three different inspection tests required under F 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 visual asfm for asmt on these test articles as defined by Table 1.
It is important to note the acceptance criterion in all cases is zero defects. For each of these types, there are also inspection criteria for coating thickness, visual f23329, and adhesion. The acceptance number in all cases is zero defects. To determine how many samples are required to test for conformance based on the lot size, F refers to Table 3 of F, Practice asmt Fastener Sampling for Specified Mechanical Properties and Performance Inspection.
Suppliers shall furnish certified test results from which the shipping lots originated. If certified aatm reports are not available, then the supplier must default to Sample Size C and conduct the tests required.
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.
For example, a lot size of articles under the detection process requires testing of 11 samples for coating thickness, 11 samples for visual appearance, and 3 samples for adhesion. According to Note C of Table 1, It is only aastm to conduct testing on samples for coating thickness once every five batch lots. 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.
ASTM F2329 vs. ASTM A153
This method is similar to an inspection of coating thickness on multi-specimen articles galvanized per ATSM A Adhesion testing is not typically performed when galvanizing to the requirements of A unless there is evidence of an adhesion concern, but F requires adhesion testing stout knife test to be performed for the number of articles listed in Table 1, and for every batch lot.
The test methods for appearance and smoothness under F shall be conducted for every batch lot by visual inspection in accordance with methods provided in A Table 2 of F lists average coating thickness requirements for production lots, batch lots, and individual specimens. A summary of the numerical differences between the two specifications related to coating thickness requirements for all materials is presented in the table: Zinc Coating Thickness Requirements: The coating thickness requirements of A Table 1 meet or exceed those of F Table 2 except for:.
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.
Each bolt specification may list additional methods to prevent hydrogen embrittlement as well as place additional requirements on embrittlement testing which should be researched separately.
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. 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.
Fasteners which are subjected to severe work hardening must be stress-relieved prior to galvanizing. It is necessary for the galvanizer to communicate the bath temperature to the customer to ensure the end user understands the effects the galvanizing temperature will have on the steel.
If the customer specifies, the galvanizer will be required to provide the average galvanizing temperature the fasteners will be exposed to.
Best practice is to note the bath temperature when galvanizing steel to F, although only the average bath temperature is required. According to F Paragraph 5. 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 t2329 chemical post-treatments, or if air-cooling will be acceptable.
Therefore, it must be clarified whether the qstm has the ability to lubricate hardware after hot-dip galvanizing. Otherwise, a third party will be required to apply the lubricant at an additional cost.
Hot-Dip Galvanizing Specifications – Portland Bolt
The amount of additional documentation beyond ASTM A requirements will vary depending on a number of optional requirements the customer can specify under F However, if a purchaser also requires the galvanizer to inspect dimensional requirements of parts upon delivery, they must provide the galvanizer with the necessary tools and inspection gauges. The material provided herein has been developed to g2329 accurate and authoritative information about after-fabrication hot-dip galvanized steel.
This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information aatm herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use. April 10, Authored by Alana Hochstein.
April 10, Authored by Bernardo A. F defines the two different lots and their associated sampling plans as follows: Coating Thickness Table 2 of Asm lists average coating thickness requirements for production lots, batch lots, and individual specimens.
The coating thickness requirements of A Table 1 meet or exceed those of F Table 2 except for: Quenching According to F Paragraph 5.