ASTM_B_998_-_17.pdf

Designation:B99817Standard 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 number 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 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 description 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.Thevalues 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 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 standard-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 casting 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:3.1.1 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.3.1.3 hot isostatic pressing(HIP),n&va solid stateprocess whereby heat and pressure are simultaneously appliedto objects in an autoclave by way of an inert gas to reduceinternal voids and obtain desired properties.Also used as averb to describe application of the process to an object,henceHIPing,HIPed.3.1.4 inert gas,na non-reactive gas,used in HIP vesselduring pressurization.3.1.5 on-line gas analysis,nanalysis of process gas ema-nating from the autoclave.Refer to 7.6(“Inert Gas Purity”).3.1.6 working zone,nthe volume of the heated region ofan autoclave which may be occupied by castings to be hotisostatically pressed.4.Significance and Use4.1 HIP of castings should be performed in the as castcondition.Post HIP inspection of castings should result in areduction of porosity that is evident in x-ray grade andproperties.4.2 HIP will not eliminate inclusions or surface-connectedporosity in a casting.5.Ordering Information5.1 Orders for HIPing of aluminum castings under thisguide should include the following information:5.1.1 This guide designation(which includes the number,year and revision letter,if applicable).1This guide is under the jurisdiction of ASTM Committee B07 on Light Metalsand Alloys and is the direct responsibility of Subcommittee B07.01 on AluminumAlloy Ingots and Castings.Current edition approved July 1,2017.Published July 2017.DOI:10.1520/B0998-17.2The HIP practice described in this guide is not intended to be substituted for theheat treat requirements for aluminum alloy castings,which are provided in PracticeB917/B917M Standard Practice for Heat Treatment of Aluminum-Alloy Castingsfrom All Processes.This standard Guide is not meant to supersede an end usersspecification where one exists.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.1.2 The quantity in pieces.5.1.3 Alloy.5.1.4 Temperature,pressure,hold time,including toler-ances.6.Equipment6.1 Autoclave:6.1.1 Autoclaves should be of the inert gas pressurizat