A. ASTM F is for inch-based fasteners and ASTM FM is for metric fasteners, although the designations are identical between the two. The fastener industry should be made aware of an important recent development in the realm of. ASTM fastener standard specifications. ASTM F/. ASTM F/FM: Standard Specification for Electrodeposited Coatings on Mechanical Fasteners, Inch and Metric.
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The appearance of corrosion products visible to the unaided eye at normal reading distance shall be cause for rejection, except when present at the awtm of the tested fasteners. The electrodeposited coating shall cover all surfaces and shall meet the following requirements: This phenomenon is accentuated with increasing length and decreasing diameter of the screw or bolt.
ASTM F – Portland Bolt
The coating material, coating thickness, chromate finish, and trivalent chromite finish shall be selected and designated. To secure uniformity of results, samples shall be aged at room temperature for 24 h before being subjected to the salt spray test. NOTE 2—With proper care many steel fasteners can be plated without baking by correlating process conditions to the susceptibility of the fastener material to hydrogen embrittlement, and by applying adequate process control procedures, such as those outlined in Appendix X4.
It also highlights the differences between barrel and rack plating and makes recommendations as to the applicability of each process. With normal methods for depositing metallic coatings from aqueous solutions, there is a risk of delayed failure due to hydrogen embrittlement for case hardened fasteners and fasteners having a hardness 40 HRC or above.
Toby — Thanks for boiling it down for me. As the barrel is moved through the process steps, it is also rotated such that the individual items are constantly cascading over one another. Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phonefaxor service astm. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.
Historical Version s – view previous versions of standard. My research is leading me to believe that ASTM F M both inch and metric are the two standards I need; but even those have over grades listed! The rack qstm designed to asym the group of items, together, through each of the process steps, allowing ready ingress and egress of processing solutions and rinses. When such areas are subject to minimum thickness requirements, the purchaser and the manufacturer shall recognize the necessity for either thicker deposits on other areas or special racking.
It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages. It specifies coating thickness, supplementary hexavalent chromate or trivalent chromite finishes, corrosion resistance, precautions for managing the risk of hydrogen embrittlement and hydrogen embrittlement relief for high-strength and surface-hardened fasteners.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. In this process, quantities of an item are placed on a support, called a rack. It assumes that the external thread pitch diameter is at the maximum and that the internal thread pitch diameter is at the minimum of the tolerance see Fig. It should be noted that modi?
Thank you for your assistance. Coating f1941, values are based on the tolerances for 1A and 2A external Uni? The other dimensional characteristics shall be as speci? Special processing is normally required for bolts with a ratio greater than 10 in order to minimize the extremity-to-center thickness ratio. High current densities increase hydrogen charging.
It is informational only and not an official part of asym standard; the full text of the standard itself must be referred to for its use and application.
That standard should be consulted for more detailed information. This standard does not purport to address all of the safety concerns, if any, associated with its use. Although this risk qstm be managed by selecting raw materials suitable for the application of electrodeposited coatings and by using modern methods of surface treatment and post heat-treatment v1941mthe risk of hydrogen embrittlement cannot be completely eliminated.
The effect of thread damage is worse on heavy? Thickness Designation 3 5 8 12 Minimum Thickness in. This standard does not purport to address all of the safety concerns, if any, associated with its use. The electrical continuity is maintained between the parts by the rack itself. For internally threaded fasteners barrel-plating is generally suitable. The coating must not cause the basic thread size to be transgressed by either the internal or external threads. It also highlights the differences between barrel and rack plating and makes recommendations as to the applicability of each process.
Ordering Information for Electroplating 5.
ASTM / ASME spec F for Zinc Plating Which finish to choose?
It specifies coating thickness, supplementary hexavalent chromate or non-hexavalent conversion coatings, corrosion resistance, precautions for managing the risk of hydrogen embrittlement and hydrogen embrittlement relief for high-strength and surface-hardened fasteners.
F9141m chromate finish letter E designates a black color.
Is there an acceptable way asfm demonstrate equivalence? Originally published as F — On an externally threaded fastener this occurs at the threaded tip. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This abstract is a brief summary of the referenced standard.
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. Measuring coating thickness on the threaded portion of a fastener is possible but impractical for in-process quality control veri? Refer to Appendix X3 as a guideline for the tolerances of the various thread sizes and classes and the coating thickness they will accommodate.
Slight discoloration that results from baking, drying, or electrode contact during rack-plating, or all of these, as well as slight staining that results from rinsing shall not be cause for rejection.
The local coating thickness on a part is a result of the electrical current density at that location.
All information presented is for general reference and does not represent a professional opinion nor the policy of an author’s employer.