Designation: G36 − 94 (Reapproved 2013)Standard Practice forEvaluating Stress-Corrosion-Cracking Resistance of Metalsand Alloys in a Boiling Magnesium Chloride Solution1This standard is issued under the f i xed designation G36; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes a procedure for conductingstress-corrosion cracking tests in a boiling magnesium chloridesolution. Although this test may be performed using variousconcentrations of magnesium chloride, this procedure covers atest solution held at a constant boiling temperature of 155.0 61.0°C (311.0 6 1.8°F). The boiling points of aqueous magne-sium chloride solutions at one atmosphere pressure as afunction of concentration are shown graphically in Fig. 1. 2 Asuggested test apparatus capable of maintaining solution con-centration and temperature within the prescribed limits forextended periods of time is also described herein. 31.2 The boiling magnesium chloride test is applicable towrought, cast, and welded stainless steels and related alloys. Itis a method for detecting the effects of composition, heattreatment, surface f i nish, microstructure, and stress on thesusceptibility of these materials to chloride stress corrosioncracking. 41.3 This practice is concerned primarily with the testsolution, which may be used with a variety of stress corrosiontest specimens, surface f i nishes, and methods of applyingstress.1.4 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. See Section 7 forspecif i c safety precautions.2. Referenced Documents2.1 ASTM Standards: 5D1193 Specif i cation for Reagent WaterG1 Practice for Preparing, Cleaning, and Evaluating Corro-sion Test SpecimensG15 Terminology Relating to Corrosion and Corrosion Test-ing (Withdrawn 2010) 6G30 Practice for Making and Using U-Bend Stress-Corrosion Test Specimens3. Terminology3.1 Def i nitions—For def i nitions of terms used in this prac-tice see Terminology G15.4. Summary of Practice4.1 A predetermined quantity of reagent grade magnesiumchloride and some distilled water are added to a container. Thecontainer and contents, with thermometer and condenseraffixed, are placed on a source of heat. When the magnesiumchloride solution boils, it is adjusted to maintain the desiredconcentration and boiling point through the addition of smallquantities of either water or salt.4.2 After the solution has stabilized at the desired boilingpoint for the test, the stressed specimens are added. Dependingupon the intent of the test, the specimens should be givenperiodic inspections. If the duration of test exceeds 7 days, thesolution should either be changed or the suggested or similartest apparatus used.5. Signif i cance and Use5.1 For most applications, this environment provides anaccelerated method of ranking the relative degree of stress-corrosion cracking susceptibility for stainless steels and related1 This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.06 on Environmen-tally Assisted Cracking.Current edition approved May 1, 2013. Published July 2013. Originally approvedin 1973. Last previous edition approved in 2006 as G36 – 94 (2006). DOI:10.1520/G0036-94R13.2 Available data on the relationship of concentrations and boiling points ofmagnesium chloride solutions are critically reviewed and supplemented by I. B.Casale in “Boiling Points of Magnesium Chloride Solutions—Their Application inStress Corrosion Studies,” Corrosion , Vol 23, 1967, pp. 314–17.3 The apparatus and test procedures for maintaining constant boiling tempera-tures of magnesium chloride solutions for stress corrosion tests are described by M.A. Streicher and A. J. Sweet in Corrosion, Vol 25, 1969, pp. 1–6.4 The use of concentrated magnesium chloride solutions for determining thesusceptibility to stress corrosion cracking of austenitic and ferritic stainless steelsand related nickel-base alloys was f i rst described by M. A. Scheil, Symposium onStress Corrosion Cracking of Metals, ASTM STP 64, ASTM, 1945, p. 395.(Although currently out of print, copies may be obtained from University Micro-f i lms, Inc., 300 North Zeeb Rd., Ann Arbor, MI 48106.)5 For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service@astm.org. For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.6 The last approved version of this historical standard is referenced onwww.astm.org.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
