ASME B18.13 pdf download

ASME B18.13 pdf download.Screw and Washer Assemblies – SEMS(Inch Series).
Proposing Revisions. Revisions are made periodically to the Standard to incorporate changes that appear necessary or desirable, as demonstrated by the experience gained from the application of the Standard. Approved revisions will be published periodically
The Committee welcomes proposals for revisions to this Standard. Such proposals should be as specific as possible, citing the paragraph number(s), the proposed wording, and a detailed description of the reasons for the proposal, including any pertinent documentation.
Proposing a Case. Cases may be issued to provide alternative rules when justified, to permit early implementation of an approved revision when the need is urgent, or to provide rules not covered by existing provisions. Cases are effective immediately upon ASME approval and shall he posted on the ASME Committee Web page.
Requests for Cases shall provide a Statement of Need and Background Information. The request should identify the Standard and the paragraph, figure, or table number(s), and be written as a Question and Reply in the same format as existing Cases. Requests for Cases should also indicate the applicable edition(s) of the Standard to which the proposed Case applies.
Interpretations. Upon request, the B18 Standards Committee will render an interpretation of any requirement of the Standard. Interpretations can only be rendered in response to a written request sent to the Secretary of the B18 Standards Committee.
Requests for interpretation should preferably he submitted through the online Interpretation Submittal Form. The form is accessible at http://go,asme.org/lnterpretationRequest, Upon submittal of the form, the Inquirer will receive an automatic e-mail confirming receipt.
If the Inquirer is unable to use the online form, he/she may e-mail the request to the Secretary of the B18 Standards Committee at the above address. The request for an interpretation should be clear and unambiguous. It is further recommended that the Inquirer submit his/her request in the following format:
(b) washer assembly and thread rolling after heat treat This Standard acknowledges these two methods of SEMS manufacture. The material choice in the first method requires skilled selection of the screw and washer materials, since the properties of each have to be realised by a single set of heat treat conditions. The selection of materials depends on the heat treat system involved, the size and shape of the washer and screw, and the austenitizing and quenching of the SEMS unit in oil. The second method is used when the desired properties of the screw and washer cannot be made by the Iirst method ol heat treating the screw and washer at the same time.
1.12.1 Method 1 — Roll Thread Before Heat Treat. In this process, a nonheat-treated bolt or screw is assembled with a nonheat-treated s’ashcr and then roll threaded as an assembly. Following threading, the assembly is heat treated simultaneously as a single unit. Since two different sets of properties must be achieved using a single heat treat process, the choice of material chemistries for both the screw and washer requires careful evaluation and selection.
1.12.2 Method 2 — Roll Thread After Heat Treat. In this process, a fully heat-treated bolt or screw blank is assembled with a fully heat-treated washer and then roll threaded to form an assembly. Following threading. no further heat treatment of the assembly is required. SEMS manufacturing using Method 2 may not be reheat treated as a corrective action.
Unless determined and stated otherwise at the time of order agreement, Method I processing is used.
NOTES:
(I) Due to work hardening, screws thread rolled after heat treatnwnt increase in core and surface hardness. This may cause the screws to have hardnesses greater than that allowed by the material specification alter thread rolling. To keep the finished screws within hardness requirements, the hardness of the screws before thread rolling will have to be somewhat lower than the final product desired hardness. This can only be determined through experimentation
(2) Method I is considered the default method and used where possible. Fkn%ever. if hardness requirenwnts are unattainable with available materials using Method I. Method 2 automaticaLly applies.