1、Designation: D7646 10Standard Test Method forDetermination of Cooling Characteristics of AqueousPolymer Quenchants for Aluminum Alloys by Cooling CurveAnalysis1This standard is issued under the fixed designation D7646; the number immediately following the designation indicates the year oforiginal ad
2、option 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 test method covers the description of the equipmentand the proced
3、ure for evaluating quenching characteristics ofaqueous polymer quenchants by cooling rate determination.1.2 This test method is designed to evaluate aqueous poly-mer quenchants for aluminum alloys in a non-agitated system.There is no correlation between these test results and the resultsobtained in
4、agitated systems.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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
5、to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D6200 Test Method for Determination of Cooling Charac-teristics of Quench Oils by Cooling Curve AnalysisE220 Test Method for Calibr
6、ation of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized Thermocouples2.2 ISO Standards:3ISO 3819 Laboratory glassware Beakers2.3 Japanese Industrial Standards:4JIS K 2242 Heat Treating Oil2.4 Wolfson Engineering Group Specific
7、ation:5Laboratory Tests for Assessing the Cooling Curve ofIndustrial Quenching Media3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 aqueous polymer quenchant, naqueous solutioncontaining a water soluble polymer; typically including poly-(alkylene glycol), poly(ethyl oxazoline)
8、, poly(sodium acrylate)and poly(vinyl pyrrolidone). The quenchant solution alsotypically contains additives for corrosion and foam control, ifneeded. Quench severity of aqueous polymer quenchants isdependent on concentration and molecular weight of thespecific polymer being evaluated, quenchant temp
9、erature, andagitation rate.3.1.2 characteristic temperature, ntransition temperaturefrom vapor blanket phase (film boiling phase) to rapid coolingphase (nucleate boiling phase) on cooling curve.3.1.3 cooling curve, ncooling curve is a graphical repre-sentation of the cooling time (t)temperature (T)
10、response ofthe probe (see 7.3). An example is illustrated in Part B of Fig.1.3.1.4 cooling curve analysis, nthe process of quantifyingthe cooling characteristics of a heat treating oil based on thetemperature versus time profile obtained by cooling a pre-heated metal probe assembly (see Fig. 2) unde
11、r standardconditions.3.1.5 cooling rate curve, nThe cooling rate curve isobtained by calculating the first derivative (dT/dt)ofthecooling timetemperature curve. An example is illustrated inPart B of Fig. 1.3.1.6 quench severity, nthe ability of a quenching me-dium to extract heat from a hot metal.3.
12、1.7 quenchant, nany medium, liquid, or gas that may beused to mediate heat transfer during the cooling of hot metal.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.L0.06 on Non-Lubricating Proce
13、ss Fluids.Current edition approved July 1, 2010. Published August 2010. DOI:10.1520/D7646-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document
14、Summary page onthe ASTM website.3Available from Society of Automotive Engineers, International, 400 Common-wealth Dr., Warrendale, PA 15096-0001.4Available from Japanese Standards Association, 4-1-24, Akasaka Minato-ku,Tokyo 1078440, Japan.5Available from Wolfson Heat Treatment Centre, Aston Univers
15、ity, AstonTriangle, Birmingham B4 7ET, England.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 Determine the silver rod probe assemblys cooling timeversus temperature after placing the assembly in a furna
16、ce andheating to 500C and then quenching in an aqueous polymerquenchant solution. The temperature inside the probe assemblyand the cooling times are recorded at selected time intervals toestablish a cooling temperature versus time curve. The result-ing cooling curve may be used to evaluate quench se
17、verity.5. Significance and Use5.1 This test method provides a cooling time versus tem-perature pathway. The results obtained by this test method maybe used as a guide in quenchant selection or comparison ofquench severities of different quenchants, new or used.6. Interferences6.1 The presence of con
18、taminants, such as oil, salt, metal-working fluids, forging lubricants, and polymer degradation,may affect cooling curve results obtained by this test methodfor aqueous polymer quenchants.7. Apparatus7.1 FurnaceUse a horizontal or vertical electrical resis-tance tube-type furnace capable of maintain
19、ing a constantminimum temperature of 850C over a heated length of notless than 120 mm and a probe positioned in the center of theheating chamber. The furnace shall be capable of maintainingthe probes temperature within 62.5C over the specimenlength. The furnace, that is, the radiant tube heating med
20、ia,shall be used with ambient atmosphere.NOTE 1Although the probe temperature is significantly lower 500Cthan the recommended furnace temperature capability 850C, this highertemperature capability is recommended since the same apparatus may beused for cooling curve analysis for steel alloys which is
21、 performed at 805to 815C.7.2 Measurement SystemThe temperaturetime measure-ment system shall be a computer based data acquisition systemcapable of providing a permanent record of the coolingcharacteristics of each oil sample tested, producing a record ofvariation in the test probe assembly of temper
22、ature with respectto time, and cooling rate with respect to temperature.7.3 ProbeShall be cylindrical, having a diameter of 10 60.1 mm and a length of 30 6 0.1 mm with a 1.0 mm sheathedType K thermocouple in its geometric center. The probe shallbe made of a silver of purity 99.99% or more. The probe
23、 shallbe attached to a support tube. See Fig. 2 for recommendedmanufacturing details. Preparation method for silver rod shallbe as follows:7.3.1 Screw the connecting rod of heatresistant steel in thesilver rod body.7.3.2 Insert the sheath type thermocouple through the sup-porting rod and supporting
24、part.7.3.3 Screw the connecting rod of heat resistant steel in thesupporting part as inserting the sheath type thermocouple in thecentral part of silver rod body.7.3.4 Screw the supporting part in the supporting rod toconnect.7.3.5 Fix the thermocouple connecting part to the support-ing rod by using
25、 a set screw while pushing the sheath typethermocouple in the direction of silver rod body. In such a case,take care so that the tip of thermocouple is completely pressedto the central part of silver rod body.7.3.6 Heat the temperature of the silver rod body andsupporting part at 700 to 800C, and co
26、at the connecting partwith the crystal of silver nitrate and joint them.7.3.7 After cooling, finish the surface smoothly by usingemery papers.Although coarser 320-grit paper may be used forinitial cleaning, the final finish shall be provided using 500-gritemery paper.7.4 Fluid VolumeThe resulting co
27、oling curve will bedependent on the temperature rise during the quench, which isdependent on the total fluid volume. Therefore, the coolingcurve analysis shall be performed with the same volume offluid.7.5 Sample Container300 mL beaker specified inISO 3819.FIG. 1 Typical Temperature/Time and Tempera
28、ture/Cooling Rate Plots for Test Probe Cooled in an Aqueous Polymer QuenchantD7646 1027.6 Temperature MeasurementAny temperature detectiondevice may be used that is capable of measuring quenchingfluid temperature to within 61C.7.7 Transfer MechanismOne of the following shall beused to transfer the h
29、eated probe from the furnace to the testfluid:FIG. 2 Probe Details and General Probe AssemblyD7646 1037.7.1 Automated Transfer MechanismThe transfer fromthe furnace to the oil shall be completed within 3.0 s. Immersethe probe in the center, 0 to 5 mm, of the fluid container to adepth where there is
30、50 6 2 mm of fluid above and below theprobe when quenched. A mechanical stop shall be used forreproducibility of probe placement.7.7.2 Manual TransferIf manual transfer is used, thesample container shall be equipped with a fixture to ensurecorrect placement in the center of the fluid container and t
31、o thedepth defined in 7.4. A timer shall be used to ensure amaximum transfer time of 3.0 s.7.8 TimerGraduated in seconds and minutes; may be partof a computer clock.7.9 Fluid VolumeThe resulting cooling curve will bedependent on the temperature rise during the quench, which isdependent on the total
32、fluid volume. Therefore, the coolingcurve analysis shall be performed with the same volume offluid.7.10 Temperature MeasurementAny temperature detec-tion device may be used that is capable of measuring quench-ing fluid temperature to within 61C.8. Reagents and Materials8.1 Reference Quenching FluidU
33、se a reference quenchingfluid for initial and regular probe calibration to determine if theprobe will give results consistent to those obtained duringinitial break-in.8.1.1 Dioctylphthalate DOP (Di-2-ethylthexyl Phthalate)Used as primary reference quenching fluid for initial calibra-tion and for per
34、iodic calibration of the probe. Properties ofDOP used as reference fluid are as follows:Density (20C): 0.986 6 0.003 g/m3Refractive index (25C): 1.485 6 0.003Water content: Not greater than 0.1 mass%Purity (GC method): Not lower than 97.0 mass%(WarningPotential acute and chronic health effects haveb
35、een reported for D.O.P. and the user shall consult the MaterialSafety Data Sheet supplied with this material prior to use andappropriate safety precautions shall be implemented duringuse.)8.1.2 Asecondary reference fluid may be used provided thatsufficient statistical cooling curve testing has been
36、conductedso that results are traceable to the primary reference fluid suchas that cited in JIS K 2242.8.1.2.1 The 10 mass% of brine solution which is preparedby dissolving sodium chloride in distilled water has also beenused as reference quenching fluid for initial calibration and forperiodic calibr
37、ation of the probe and the total system.8.2 Cleaning SolventA hydrocarbon solvent that willevaporate at room temperature, leaving no residue.(WarningFlammable. Harmful if inhaled.)8.3 Polishing Paper500 grit emery.8.4 ClothLint-free and absorbent.9. Cleaning and Polishing9.1 Cleaning Used ProbesWipe
38、 probe with a lint-freecloth or absorbent paper after removal from the quenchant andprior to returning to the furnace. (WarningThe probe shallalways be considered hot, as temperature below visual hottemperatures can still cause injury to the skin.) A cleaningsolvent may be used, but care should be t
39、aken that the probe isbelow 50C. (WarningDo not use cleaning solvent near thefurnace opening, especially with automated transfer mecha-nisms.). Water may be also be used as a cleaning solvent whichmay by followed by polishing (see 9.2).9.2 Polishing Used Probes Using Emery PaperPolishprobe surface l
40、ightly at every trial using 500-grit emery paperuntil its metallic luster is recovered.10. Sampling10.1 Sampling shall be in accordance with 7.5. Take care toensure the sample is representative of the quenchant beingtested. Use a clean and dry sample container.11. Preparation of Apparatus11.1 Prehea
41、t furnace to 520 to 550C.11.2 Connect a dry, cleaned, calibrated probe to the transfermechanism in accordance with equipment manufacturers in-structions.11.3 The aqueous polymer quenchant shall be heated orcooled to the desired temperature if production testing is beingperformed, or to 80C if the re
42、ference fluid dioctylphthalate(DOP) is being tested.12. Calibration and Standardization12.1 Probe:12.1.1 Check the accuracy of the probe thermocouple byattaching a previously calibrated thermocouple to the outersurface of the probe. Locate the tip of the calibrated thermo-couple 15 mm from the end o
43、f the probe. Heat the probe andcalibrated thermocouple to the selected furnace temperature of510 6 5C, and allow to equalize. Compare the outputs of boththe furnace and probe thermocouples by any calibrated tem-perature measuring device capable of required accuracy, asdescribed in Test Method E220 a
44、nd Specification E230.12.1.2 Frequency of Probe CalibrationCalibrate theprobe against a reference quenching fluid before each set of testruns.12.1.2.1 Use a reference quenching fluid for initial andregular probe calibration to determine if the probe will giveresults consistent to those obtained duri
45、ng initial break-in. Thedioctylphthalate (DOP) and the 10 mass% of brine solution,which is prepared by dissolving sodium chloride in distilledwater, shall be used.(1) Probe Calibration by DOPEmploy DOPat 80C, andrecord the cooling curve from 810 6 5C. In such cases, thecharacteristic temperature sha
46、ll be 495 6 10C and the coolingtime in seconds from 800C to 400C shall be 5.0 6 0.3 s.(2) Probe Calibration by Brine SolutionEmploy 10%brine solution at 30C and record the cooling curve form 8106 5C. In such a case, the cooling time in seconds from 600Cto 300C shall be within 0.3 s.When these calibr
47、ation references are not satisfied, disas-semble the silver probe and assemble it again, polish thesurface to make it flat, and calibrate it again.12.2 Equipment CalibrationCalibrate desired recordingmechanism, as described in Annex A1 in Test Method D6200.D7646 10412.3 Total System CalibrationCalib
48、rate the system with areference quenching fluid (see 8.1) following the proceduredescribed in Section 13. Calibrate the system prior to using anew probe for testing and before and after each new set of testruns. The limits of the results obtained on the reference fluidshall be established for each r
49、eference fluid prior to use, asdescribed in 12.1.13. Procedure13.1 Place the probe in the preheated furnace. Bring theprobe temperature to the required temperature of 510 6 5C,and soak at this temperature for at least 2 min.13.2 Transfer rapidly the probe to the center of the quen-chant sample, activating the data collection equipment at thesame time. At this time, the silver probe shall be immersed tothe depth where its lower end is 15 mm above the bottom of thecontainer (WarningElectric resistance type furna
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