1、Designation: B998 17Standard Guide forHot Isostatic Pressing (HIP) of Aluminum Alloy Castings1This standard is issued under the fixed designation B998; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide presents requirements for hot isostatic press-ing (HIP) of aluminum alloy castings. HIPing is a process inwhich components are
3、 subjected to the simultaneous applica-tion of heat and high pressure in an inert gas medium. Theprocess is to be used for the reduction of internal (non-surfaceconnected) porosity. The document is to describe the generalparameters of the HIP process, describe certification proce-dures and a descrip
4、tion that the process has been followed. It isnot intended to be a description of a heat treating procedure.This is not meant to supersede an end users specificationwhere one exists.21.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalue
5、s stated in each system may not be exact equivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with
6、its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on stand
7、ard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 The following documents of the issue in effect on thedate of c
8、asting purchase form a part of this practice to theextent referenced herein:2.2 ASTM Standards:E230/E230M Specification for Temperature-ElectromotiveForce (emf) Tables for Standardized Thermocouples2.3 AMS StandardsAMS 2750 Pyrometry3. Terminology3.1 Definitions of Terms Specific to This Standard:3.
9、1.1 autoclave, na pressure vessel used in the HIPprocess.3.1.2 hold time, ntime at required temperature and pres-sure as specified on the drawing or applicable specification.Hold time to start when pressure and all temperature hold timeload monitoring thermocouples are within specified require-ments
10、.3.1.3 hot isostatic pressing (HIP), n autoclave; densification; HIP; HIP-ing; hot isostatic pressing; internal voids; inert gases; porosity;pressure; thermal couple; thermal treatmentTABLE 2 Allowable Inert Gas ImpuritiesImpurityMaximum VolumePresentPPM (Vol/Vol)Nitrogen 0.0050 50Hydrogen 0.0125 12
11、5Oxygen 0.0025 25Hydrocarbons (Methane, CH4) 0.0025 25B998 173ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such
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