6303 International Standard (ISO Pressure vessel steels not included in ISO 2604, Parts 1 to 6 - Derivation of long-time stress rupture properties Produits en acier pour récipients a pression ne figurant pas dans I'isO 2604, Parties 1a 6-Derivation des proprietes de rupture souscontrainteprolongée First edition - 1981-03-01 ISO 6303-1981 (E) UDC 669.14.018.452 : 620.172.251.2 Ref.No. ISO 6303-1981 (E) Descriptors : steels, pressure vessels, mechanical properties, rupture stress, tests, sampling, test specimen conditioning. Price based on 5 pages Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards institutes (Iso member bodies). The work of developing Inter- national Standards is carried out through Iso technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations,governmental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the memberbodies for approval before their acceptance as International Standards by the Iso Council. International Standard ISO 6303 was developed by Technical Committee ISO/TC 17, Steel,andwascirculatedtothememberbodiesinNovember1979. It has been approved by the member bodies of the following countries : Australia India Romania Austria Italy South Africa, Rep. of China Japan Spain Czechoslovakia Korea, Dem. P. Rep. of Sweden Denmark Korea, Rep.of Switzerland Egypt, Arab Rep. of Netheriands United Kingdom Finland New Zealand USSR France Norway Germany, F. R. Poland The member body of the following country expressed disapproval of the document on technical grounds : Belgium International Organization for Standardization, 1981 Printed in Switzerland ISO 6303-1981 (E) INTERNATIONALSTANDARD Pressure vessel steels not included in ISO 2604 Parts 1 to 6 - Derivation of long-time stress rupture properties 0 Introduction b) where properties different from those internationally agreed are being claimed (for example, in instances where a In the Iso rules for the construction of stationary boilers standard specifies a restricted or extended composition or (ISO/R 831) and the draft rules for the construction of unfired heat-treatment range). pressure vessels, mean stress for rupture in 100 000 h is listed as an alternative design criterion. The purpose of specifying a standard procedure is to minimize any differences in long-time estimates obtained in different International Standards for pressure vessel steels contain mean countries due to values for stress to give rupture in 100 000 h and longer times which have been internationally agreed. For products supplied a) differences in the quantity and duration of the data to these International Standards or national standards con- used to establish the estimates; forming with the relevant International Standards, the stress rupture values given in the international Standards are valid b) differences in the method of analysing the data. provided that Details of the method of extrapolation used in the analysis of a) the product has been n manufactured strictly creep rupture data are given in the annex. accordance with the technical requirements of the relevant Internationai Standard; References b) the manufacturer supplies a statement to this effect. ISO/R 206, Creep stress rupture testing of steel at elevated In all other cases, it is necessary to assure the manufacturer of temperatures. the vessel that the product supplied is capable of meeting the values given in a national standard or other specification ISO/R831,Rules for construction of stationary boilers a) by adequate records of test results on the type of steel concerned,and 3 General b) by a statement that the manufacturing processes have The stress rupture strength of a steel depends upon various remained equivaient to th