1、Designation: D7646 10 (Reapproved 2014)Standard 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
2、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 test method covers the description of the equip
3、mentand the procedure 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 r
4、esultsobtained in 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
5、 of this standard 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
6、 Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized Thermocouples2.2 ISO Standards:3ISO 3819 Laboratory GlasswareBeakers2.3 Japanese Industrial Standards:4JIS K 2242 Heat Treating Oil2.4 Wolfson Engineeri
7、ng Group Specification:5Laboratory Tests for Assessing the Cooling Curve of Indus-trial 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), po
8、ly(ethyl oxazoline), 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 evalua
9、ted, quenchant temperature, 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
10、(t)temperature (T) 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 assembl
11、y (see Fig. 2) under 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 mediumto extract heat fr
12、om a hot metal.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.L0.06 on Non-Lubricating Process Fluids.Current edition approved Dec. 1, 2014. Published February 2015. Originallyap
13、proved in 2010. Last previous edition approved in 2010 as D7646 10.DOI:10.1520/D7646-10R14.2For 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 Su
14、mmary 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 Universit
15、y, AstonTriangle, Birmingham B4 7ET, England.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.7 quenchant, nany medium, liquid, or gas that may beused to mediate heat transfer during the cooling of hot metal.4. Summary of Test Meth
16、od4.1 Determine the silver rod probe assemblys cooling timeversus temperature after placing the assembly in a furnace 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
17、toestablish a cooling temperature versus time curve. The result-ing cooling curve may be used to evaluate quench severity.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 selec
18、tion or comparison ofquench severities of different quenchants, new or used.6. Interferences6.1 The presence of contaminants, such as oil, salt, metal-working fluids, forging lubricants, and polymer degradation,may affect cooling curve results obtained by this test methodfor aqueous polymer quenchan
19、ts.7. Apparatus7.1 FurnaceUse a horizontal or vertical electrical resis-tance tube-type furnace capable of maintaining 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 maintai
20、ningthe probes temperature within 62.5C over the specimenlength. The furnace, that is, the radiant tube heating media,shall be used with ambient atmosphere.NOTE 1Although the probe temperature is significantly lower 500Cthan the recommended furnace temperature capability 850C, this highertemperature
21、 capability is recommended since the same apparatus may beused for cooling curve analysis for steel alloys which is 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 co
22、olingcharacteristics of each oil sample tested, producing a record ofvariation in the test probe assembly of temperature 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 sheathed
23、Type K thermocouple in its geometric center. The probe shallbe made of a silver of purity 99.99% or more. The probe 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 heatresistan
24、t steel in thesilver rod body.7.3.2 Insert the sheath type thermocouple through the sup-porting rod and supporting 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 support
25、ing part in the supporting rod toconnect.7.3.5 Fix the thermocouple connecting part to the support-ing rod by using 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
26、part of silver rod body.7.3.6 Heat the temperature of the silver rod body andsupporting part at 700 to 800C, and coat 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
27、 forinitial cleaning, the final finish shall be provided using 500-gritemery paper.FIG. 1 Typical Temperature/Time and Temperature/Cooling Rate Plots for Test Probe Cooled in an Aqueous Polymer QuenchantD7646 10 (2014)2FIG. 2 Probe Details and General Probe AssemblyD7646 10 (2014)37.4 Fluid VolumeTh
28、e resulting cooling 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 in ISO3819.7.6 Temperature MeasurementAn
29、y 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 heated probe from the furnace to the testfluid:7.7.1 Automated Transfer MechanismThe transfer fromthe furnace to the
30、 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 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
31、 used, thesample container shall be equipped with a fixture to ensurecorrect placement in the center of the fluid container and to 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 Fl
32、uid VolumeThe resulting cooling 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.7.10 Temperature MeasurementAny temperature detec-tion device may be use
33、d that is capable of measuring quench-ing fluid temperature to within 61C.8. Reagents and Materials8.1 Reference Quenching FluidUse 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.
34、1 Dioctylphthalate DOP (Di-2-ethylthexyl Phthalate)Used as primary reference quenching fluid for initial calibra-tion and for periodic 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
35、: Not greater than 0.1 mass%Purity (GC method): Not lower than 97.0 mass%(WarningPotential acute and chronic health effects havebeen 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 implem
36、ented duringuse.)8.1.2 Asecondary reference fluid may be used provided thatsufficient statistical cooling curve testing has been 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
37、 sodium chloride in distilled water has also beenused as reference quenching fluid for initial calibration and forperiodic calibration of the probe and the total system.8.2 Cleaning SolventA hydrocarbon solvent that willevaporate at room temperature, leaving no residue.(WarningFlammable. Harmful if
38、inhaled.)8.3 Polishing Paper500 grit emery.8.4 ClothLint-free and absorbent.9. Cleaning and Polishing9.1 Cleaning Used ProbesWipe 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
39、temperature below visual hottemperatures can still cause injury to the skin.) A cleaningsolvent may be used, but care should be taken 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 a
40、s a cleaning solvent whichmay by followed by polishing (see 9.2).9.2 Polishing Used Probes Using Emery PaperPolishprobe surface lightly 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 sa
41、mple is representative of the quenchant beingtested. Use a clean and dry sample container.11. Preparation of Apparatus11.1 Preheat 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 p
42、olymer quenchant shall be heated orcooled to the desired temperature if production testing is beingperformed, or to 80C if the reference fluid dioctylphthalate(DOP) is being tested.12. Calibration and Standardization12.1 Probe:12.1.1 Check the accuracy of the probe thermocouple byattaching a previou
43、sly calibrated thermocouple to the outersurface of the probe. Locate the tip of the calibrated thermo-couple 15 mm from the end of 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 pr
44、obe thermocouples by any calibrated tem-perature measuring device capable of required accuracy, asdescribed in Test Method E220 and Specification E230.12.1.2 Frequency of Probe CalibrationCalibrate the probeagainst a reference quenching fluid before each set of test runs.12.1.2.1 Use a reference que
45、nching fluid for initial andregular probe calibration to determine if the probe will giveD7646 10 (2014)4results consistent to those obtained during initial break-in. Thedioctylphthalate (DOP) and the 10 mass% of brine solution,which is prepared by dissolving sodium chloride in distilledwater, shall
46、 be used.(1) Probe Calibration by DOPEmploy DOPat 80C, andrecord the cooling curve from 810 6 5C. In such cases, thecharacteristic temperature shall 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 3
47、0C 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 calibration 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 Eq
48、uipment CalibrationCalibrate desired recordingmechanism, as described in Annex A1 in Test Method D6200.12.3 Total System CalibrationCalibrate the system with areference quenching fluid (see 8.1) following the proceduredescribed in Section 13. Calibrate the system prior to using anew probe for testin
49、g and before and after each new set of testruns. The limits of the results obtained on the reference fluidshall be established for each reference 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
