1、Designation: G124 10Standard Test Method forDetermining the Combustion Behavior of Metallic Materialsin Oxygen-Enriched Atmospheres1This standard is issued under the fixed designation G124; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 test method covers test apparatus and techniques todetermine the minimum test gas pressure and
3、 sample tempera-ture that supports self-sustained burning and the regression rateof the melting surface of a standardized sample of a metallicmaterial that has been ignited using a promoter.1.2 The data obtained from this test method are dependenton the precise test sample configuration and provide
4、a basis forcomparing the burning characteristics of metallic materials. Nocriteria are implied for relating these data for the suitability ofa materials use in any actual system.1.3 Requirements for apparatus suitable for this test methodare given, as well as an example. The example is not requiredt
5、o be used.1.4 This test method is for gaseous oxygen or any mixtureof oxygen with inert diluents that will support burning, at anypressure or temperature within the capabilities of the apparatusused.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses
6、are for informationonly.1.6 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 prio
7、r to use.2. Referenced Documents2.1 ASTM Standards:2G63 Guide for Evaluating Nonmetallic Materials for Oxy-gen ServiceG88 Guide for Designing Systems for Oxygen ServiceG93 Practice for Cleaning Methods and Cleanliness Levelsfor Material and Equipment Used in Oxygen-EnrichedEnvironmentsG94 Guide for
8、Evaluating Metals for Oxygen Service3. Terminology3.1 Definitions:3.1.1 burn length, nthe burn length is the length of thesample that has been consumed by combustion.3.1.1.1 DiscussionThe burn length is determined by sub-tracting the post-test sample length from the pretest samplelength (which does
9、not include the promoter length or regionused by the test sample support.)3.1.2 flammable material, na material is defined in thisstandard as flammable if a standard rod sample burns morethan 3 cm (1.2 in.) above the promoter (1, 2).33.1.3 highest no-burn pressure, nthe maximum gas pres-sure (at a s
10、pecified oxygen concentration and fixed sampletemperature) at which a material does not burn more than 3 cm(1.2 in.) above the promoter in a minimum of five tests.3.1.4 highest no-burn temperature, nthe maximumsample temperature (at a specified oxygen concentration andpressure) at which a material d
11、oes not burn more than 3 cm(1.2 in.) above the promoter in a minimum of 5 tests.3.1.5 igniter, na material used to ignite the promoter thatcan burn under an electrical influence, such as a small-diameterwire.3.1.6 lowest burn pressure, nthe minimum gas pressure(at a specified oxygen concentration an
12、d fixed sample tempera-ture) at which a material burns more than 3 cm (1.2 in.) abovethe promoter for one or more tests specimens.3.1.7 lowest burn temperature, nthe minimum sampletemperature (at a specified oxygen concentration and pressure)at which a material burns more than 3 cm (1.2 in.) above t
13、hepromoter for one or more tests specimens.3.1.8 promoter, nan optional material that can add supple-mental heat and increase the temperature to start burning of themetallic material being tested.3.1.9 regression rate of the melting interface, nthe aver-age rate at which the solid-liquid metal (melt
14、ing) interfaceadvances along the test sample length during a test.1This test method is under the jurisdiction of ASTM Committee G04 onCompatibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and isthe direct responsibility of Subcommittee G04.01 on Test Methods.Current edition appro
15、ved Nov. 1, 2010. Published November 2010. Originallyapproved in 1994. Last previous edition approved in 2003 as G124 95 (2003).DOI: 10.1520/G0124-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStand
16、ards volume information, refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.
17、1.10 sample temperature, nthe initial temperature of thetest sample being evaluated.3.1.10.1 DiscussionVarious methods of measuringsample temperatures are used. The method selected must bereported with test data.3.1.11 standard rod test sample, na 3.2 mm (0.125 in.)diameter rod with a minimum length
18、 of 101.6 mm (4 in.).3.1.12 threshold pressure, nThis term is historically usedto represent the definitions of either the lowest burn pressure orthe highest no-burn pressure.3.1.12.1 DiscussionIn this standard, it represents the low-est burn pressure, which is used as the new term throughout.3.1.13
19、valid test, na test in which the igniter and/orpromoter combination has melted the bottom section of the testsample where the igniter and/or promoter is located.4. Summary of Test Method4.1 A standard rod sample of the material to be tested isvertically suspended in a chamber filled with pressurized
20、 testgas. The chamber contains sufficient oxygen so that not morethan 10 % of the oxygen will be consumed if the samplecompletely burns. A promoter (aluminum is most common,however titanium, carbon steel and magnesium are also used)may be applied to the bottom of the rod to start burning of themater
21、ial in conjunction with the igniter (typically Pyrofuse orNichrome wire)4. The test chamber is pressurized to therequired test pressure and the sample is heated to the requiredtest temperature (if elevated temperature is one of the param-eters).4.2 The test is initiated by ignition of the igniter wi
22、re/promoter (typically through resistive heating) so that the end ofthe test sample is melted away to produce a valid test withrelevant data collected, as specified.NOTE 1In 4.3 as subsequent samples are tested, only one parameter oftemperature or pressure is varied and the other held constant withi
23、n thetolerance allowed by this test method. It is up to the user to determine ifthe purpose of the test is to determine burn/no-burn pressure or burn/no-burn temperature. Only one of these variables should be changed duringa series of tests.4.3 If the sample is flammable, another standard sample rod
24、is tested at a reduced test pressure or temperature. If the sampleis not flammable, testing continues until the sample is notflammable in a minimum of fivetests at one set of conditions.It has been shown, for a burn probability of less than 10 %, 5no burn results provides a 41 % confidence level in
25、the (noburn) result, whereas twenty-two no burn results provides a90 % confidence level (for the same burn probability of 10 %).A thorough discussion of the burn probabilities and associatedconfidence levels is given in Ref (3).NOTE 2Increasing the number of samples will always give a higherlevel of
26、 confidence and is recommended when possible. This methoddefines the highest no-burn pressure or temperature and the lowest burnpressure or temperature. The maximum no-burn (and burn) temperatureand pressure and regression rate of the melting interface can be deter-mined from the test data.5. Signif
27、icance and Use5.1 This test method will allow comparisons of the burningcharacteristics of various metallic materials. The burningcharacteristics that can be evaluated include (1) burn andno-burn pressure, (2) burn and no-burn temperature, (3)regression rate of the melting interface, and (4) visual
28、evalua-tion of the burning process of the test sample.6. Interferences6.1 Any materials inside the test chamber that may bake out,ignite/burn, or vaporize during the burning process at testtemperature/pressure may interfere with the chemistry of thefire propagation and subsequently affect burning.6.
29、2 The specific atmosphere in the test chamber can have asevere chemical or thermodynamic effect, or both. Therefore,test gas contamination or diluents (such as argon, nitrogen,carbon dioxide, water vapor, and others) can be importantfactors, so the oxygen gas purity and quantities and types ofdiluen
30、ts should be specified in the data sheet.6.3 The standard test is conducted under non-flowing con-ditions. Depending on the final gas velocity, tests conductedunder flowing oxygen conditions may dramatically affect thetest results.7. Apparatus7.1 SystemA schematic of a typical system is shown inFig.
31、 1. Other designs may also be used if they fulfill thefollowing requirements.7.2 Test ChamberA cross-section of a typical test cham-ber is shown in Fig. 2. Appendix X1 provides criteria forestablishing the lowest test pressures that meet the statedcriterion of using no more than 10 % of the availabl
32、e oxidizerfor various vessel volumes. If the chamber cannot be madesufficiently large, an accumulator can be attached between thetest chamber and the chamber isolation valve that containsmore test gas. The test chamber (and accumulator if used) shallnot contribute any chemical interference to testin
33、g.7.3 Sample Holdercapable of securing the sample at thetop and supporting it in a vertical position.7.4 Temperature Sensorused to measure gas or sampletemperatures in the chamber, accurate to within 61% ofreading or accuracy otherwise noted.7.5 Pressure Transducerused to measure gas pressure inthe
34、chamber, accurate to within 61 % of reading or accuracyotherwise noted.7.6 Liner (optional)a burn-resistant (for example, copperor ceramic) liner is recommended in the test chamber to serveas an internal shield to protect the chamber and componentsfrom the burning, molten slag, and other reaction pr
35、oductsproduced during sample burning.7.7 Sight Glass(optional for tests not determining eitherthe regression rate of the melting interface or visual evaluationof the burning process), capable of withstanding the maximumtest pressure anticipated (initial pressure plus pressure rise dueto heating duri
36、ng burning). Other methods of observing the testmay be possible, though direct observation is most common.7.8 Igniter Power Supplyelectrically isolated and capableof providing adequate current to initiate the ignition within 3 sof the application of power.4The trade name for aluminum-palladium wire
37、is Pyrofuze. It is a registeredtrademark of the Pyrofuze Corp., 121 S. Columbus Ave., Mt. Vernon, NY 10553,and is available from them.G124 1027.9 Test Cella room to house the test chamber, con-structed of non-flammable material (such as concrete or metal)with sufficient strength to provide protectio
38、n from explosion,pneumatic release or fire hazards. A continuous ventilationsystem shall circulate fresh air in the test cell.The test cell shallbe cleaned periodically to avoid contamination of the sampleand equipment and minimize fire hazards.7.10 Piping System which purges, pressurizes, and vents
39、the test chamber. The piping system shall be designed to permitremote test chamber purge, pressurization, and venting withoutunsafe exposure of personnel. It is recommended the testchamber be purged and pressurized through one line andvented through a separate line to minimize the chances of acontam
40、inant migrating into the pressurization line, whichmight influence subsequent tests. It is also recommended that apressure relief device with an appropriate setting be fitted to thepiping system and be able to communicate to the test chamber.NOTE 3Although the use of separate lines is preferred it i
41、s not arequirement. Periodic inspection and cleaning of lines and valves shouldbe done to decrease the risk of cross contamination. A typical pipingsystem for this test is shown in Fig. 1.7.11 Control Areawhich will isolate test personnel fromthe test cell during tests. This control area shall be pr
42、ovidedwith the necessary control and instrumentation features toperform test chamber purge, pressurization and venting opera-tions, and monitoring of the test chamber instrumentationduring the test.7.12 Data Acquisition Systemcapable of recording, stor-ing, and accessing the pressure, temperature an
43、d regression ratedata at a rate of ten samples per second (minimum). It may alsoinclude a video recording device that displays the “real-time”burn phenomenon. The video recording with embedded timer,thermocouple sensor arrays, and ultrasonic rod length measure-ments are some of the methods available
44、 for determination ofthe regression rate of the melting interface (see Annex A1).7.13 Heating System (for elevated temperature testingonly)which will heat the sample to the required initial testsample temperature range, without interfering with the otherfunctions of the test system or the test chamb
45、er integrity. Theheating system is required to evaluate burning characteristics atelevated temperatures above ambient. (No heating system isrequired if testing is to be done at ambient temperature only.)The method used can include, but is not limited to, localizedheating methods including induction
46、heating, resistive heating,and radiant heating. Heating of the entire system has also beensuccessfully used, however the vessel pressure rating must beconsidered due to the temperature dependency of the chambermaterial strength (see 9.4) and any non-metallic materialsexposed to elevated temperatures
47、 should be used in accordancewith Guide G63.8. Reagents and Materials8.1 Gaseous OxygenOxygen purity equal to or greaterthan that of practical systems is preferred for the standard test,and an analysis of the test oxidant is required. Other oxygen/diluents mixtures may be used and it is recommended
48、that theexact oxygen purity used be specified with the test results. (4)NOTE 4Oxygen purity has been shown, for certain materials tosignificantly affect the results. Extremely high purity or low purity oxygen(with diluents present) should be avoided unless conducting specialstudies using gas mixture
49、s (5) and in all cases the purity should beFIG. 1 Schematic of Typical SystemFIG. 2 Typical Stainless Steel Test Chamber Cross-SectionG124 103specified along with any diluents present8.2 PromoterThe promoter shall provide sufficient energyto melt the end of the test sample to produce a valid test and,if flammable at test conditions, ignite the test specimens. Someexamples of promoter material include aluminum, Pyrofuze,4magnesium, titanium and carbon steel (6). In some cases, apromoter may not be necessary when the igniter itself canprovide suff
