Bringing mold material thermophysical data up to speed: because of the ever-growing functionality of casting process modeling programs, mold material thermal input data have been evaluated and redefined.With the rapid increase in advancements in physics-based mold mold, name for certain multicellular organisms of the various classes of the kingdom Fungi, characteristically having bodies composed of a cottony mycelium. The colors of molds are caused by the spores, which are borne on the mycelium. filling and solidification so·lid·i·fy v. so·lid·i·fied, so·lid·i·fy·ing, so·lid·i·fies v.tr. 1. To make solid, compact, or hard. 2. To make strong or united. v.intr. simulation software Simulation software is based on the process of imitating a real phenomenon with a set of mathematical formulas. It is, essentially, a program that allows the user to observe an operation through simulation without actually running the program. , the need to bring material thermal properties up to speed has be come readily apparent. Constant advances in simulation technology have helped drive the increasing functionality and use of simulation tools, and thus, have placed a new emphasis on the quality" and accuracy of the current material property thermal datasets. The generic thermal data for mold material commonly used is more than 20 years old. Not surprisingly, output data accuracy for simulation programs is severely affected by the inaccuracies in the mold material thermal input data. With all the changes in binder binder: see combine. An earlier Microsoft Office workbook file that let users combine related documents from different Office applications. The documents could be viewed, saved, opened, e-mailed and printed as a group. technology and the advent of more sophisticated measurement devices, an obvious need to quantify Quantify - A performance analysis tool from Pure Software. , as accurately as possible, the thermal characteristics of several mold material types exists. This article details the results of an evaluation of mold materials' thermal properties to establish a baseline The horizontal line to which the bottoms of lowercase characters (without descenders) are aligned. See typeface. baseline - released version for the type of binder system and silica silica or silicon dioxide, chemical compound, SiO2. It is insoluble in water, slightly soluble in alkalies, and soluble in dilute hydrofluoric acid. Pure silica is colorless to white. sand morphology morphology In biology, the study of the size, shape, and structure of organisms in relation to some principle or generalization. Whereas anatomy describes the structure of organisms, morphology explains the shapes and arrangement of parts of organisms in terms of such specific to green sand and resin-bonded sand mold materials. The project focused on five different sand samples (Table 1), including chemically bonded urethane urethane (yoor´ithān´), n ethyl carbamate used as an anesthetic agent for laboratory animals, formerly used as a hypnotic in humans. molding sand--core (CBUMS-C), chemically bonded urethane molding sand--mold (CBUMS-M), chemically bonded shell molding sand--mold (CBSMS-M), chemically bonded furan furan: see furfural. molding sand--core (CBFMS-C), chemically bonded furan molding sand--mold (CBFMS-M), green sand machine molded mold 1 n. 1. A hollow form or matrix for shaping a fluid or plastic substance. 2. A frame or model around or on which something is formed or shaped. 3. Something that is made in or shaped on a mold. (GS-MM) and green sand--high-pressure molding sand (Founding) a kind of sand containing clay, used in making molds. See also: Molding (GS-HPMS). Getting Started In general, the thermal property database for cast metals appears to be accurate and growing daily. Likewise, thermal properties for insulating and exothermic exothermic /exo·ther·mic/ (-ther´mik) marked or accompanied by evolution of heat; liberating heat or energy. ex·o·ther·mic or ex·o·ther·mal adj. 1. riser sleeves have been developed in recent years and also appear to be accurate. Thermal properties for mold materials, on the other hand, have not been evaluated in decades. Extensive measurements were made between 1950 and 1985, and a significant array of mold material thermal properties has been documented. But recent work has shown that old information may underestimate the thermal heat transfer of some molding materials. In general, it is recommended that metalcasting facilities test their specific molding media composition for thermal properties to obtain the most accurate dataset See data set. particular to their respective operation. However, that is not always practical, so a need exists to define a new, more accurate set of general thermal properties for various molding materials. Method of Analysis Specific heat test measurements were performed using the Bunsen Ice Calorimeter calorimeter: see calorimetry. calorimeter Device for measuring heat produced during a mechanical, electrical, or chemical reaction and for calculating the heat capacity of materials. . Density values, as a function of temperature, were obtained from thermal expansion thermal expansion Increase in volume of a material as its temperature is increased, usually expressed as a fractional change in dimensions per unit temperature change. measurements of the mold material sample and mass change data (as determined from the specific heat measurements). The measurements were made in a dilatometer dil·a·tom·e·ter n. An instrument used to measure thermal expansion and dilation in solids and liquids. [dilate + -meter. . Thermal diffusivity In heat transfer analysis, thermal diffusivity (symbol:  ) is the ratio of thermal conductivity to volumetric heat capacity.2. The act of congress of July 4, 1836, section 6, requires the inventor or discoverer of an invention or discovery to accompany his petition and specification for a patent with specimens thickness. Sampling guidelines guidelines, n.pl a set of standards, criteria, or specifications to be used or followed in the performance of certain tasks. with respect to the size of the sample, collection, storage, packing and transportation were developed and followed. Samples of an approximate size of 3 x 5 x 5 in. were collected from the parting surface and stored in airtight air·tight adj. 1. Impermeable by air. 2. Having no weak points; sound: an airtight excuse. airtight Adjective 1. bags to preserve moisture. New Guidelines To accurate[y measure the thermal properties of mold materials, tests must be conducted on material taken from several locations on the sample to ensure valid results. In addition, thin slices of the material must be taken to conduct the thermal diffusivity tests. However, these samples can sometimes slump Slump A temporary fall in performance, often describing consistently falling security prices for several weeks or months. at high temperatures and give false diffusivity Dif`fu`siv´i`ty n. 1. Tendency to become diffused; tendency, as of heat, to become equalized by spreading through a conducting medium. readings. Some mold materials are nearly impossible to test because small samples undergo phase changes at high temperatures. This study was not immune to problems of this nature. Of the seven mold materials tested, complete datasets will be presented for only five materials. Further evaluation is required on the remaining two datasets, primarily in the area of thermal diffusivity measurements. (Partial datasets including specific heat and density will be presented for these two materials). Chemically Bonded Mold Materials Comparisons were made between measurements for the chemically bonded materials (CBUMS-M, CBFMS-C and CBSMS-M) and a generic dataset for chemically bonded mold materials currently available in most simulation software packages. The generic dataset for the thermal conductivity thermal conductivity A measure of the ability of a material to transfer heat. Given two surfaces on either side of the material with a temperature difference between them, the thermal conductivity is the heat energy transferred per unit time and per unit values matches the CBUMS-M data. The CBFMS-C core sand molding material data have a lower thermal conductivity for temperatures below 1,400C (2,552F) ant slightly higher thermal conductivity for temperatures ranging from 1,5001,600C (2,732-2,912F). The CBSMS-M dataset has a slightly higher thermal conductivity at temperatures below 600C (1,112F) and significantly lower thermal conductivity at temperatures above 600C. Specific heat values for CBUMS-M, CBFMS-C CBSMS-M and CBUMS-C datasets are slightly higher than the generic data. (Because the CBSMS-M data and the generic data were both measured on a differential scanning calorimeter, their datasets have a slightly different correlation trend at very low temperatures, as compared to the datasets measured using the Bunsen Ice Calorimetry calorimetry (kăl'ərĭm`ətrē), measurement of heat and the determination of heat capacity method.) The CBUMS-M, CBFMS-M and generic data share similar density traits. The density for the core sand samples (CBFMS-C and CBUMS-C) are about 1015% higher than the generic data, while the shell sand sample (CBSMS-M) density data are about 10% lower than the generic data. While there are several ways to evaluate the new thermal data, a proven method involves pouring castings, taking thermocouple reading in the mold and sectioning solidified so·lid·i·fy v. so·lid·i·fied, so·lid·i·fy·ing, so·lid·i·fies v.tr. 1. To make solid, compact, or hard. 2. To make strong or united. v.intr. feeders. The theory is that if the fee pipe can be predicted accurately i conjunction with the temperature profile in the molding material, then the molding material thermal data are probably accurate. This theory also implies that the thermal data for the feeding system also must be accurate, along with the heat transfer coefficients The heat transfer coefficient is used in calculating the convection heat transfer between a moving fluid and a solid in thermodynamics. The heat transfer coefficient is often calculated from the Nusselt number (a dimensionless number). between the metal and the sleeve One example of this involves purely insulating riser sleeve on a cub casting that is poured in low-carbon alloy alloy (ăl`oi, əloi`) [O. Fr.,=combine], substance with metallic properties that consists of a metal fused with one or more metals or nonmetals. steel at 1,560C (2,840F). The molding material is chemically bonded with urethane, and the riser sleeve is 4 x 6-in. insert sleeve that is top risered on a 5.5-in. cube cube, in geometry, regular solid bounded by six equal squares. All adjacent faces of a cube are perpendicular to each other; any one face of a cube may be its base. The dimensions of a cube are the lengths of the three edges which meet at any vertex. . Several identical castings were poured in several molds and thermocouples were placed at the riser sleeve outer diameter (sleeve/ mold interface) and at 0.25 in. and 0.5 in. deep in the molding material. Simulations were conducted using the CBUMS-M molding material thermal data to measure the performance results of feed safety margin. (The feed safety margin is defined as the distance from the bottom of the pipe to the riser/casting interface divided by the poured height of the riser.) The predicted results (Figs. 1-2), show a 13.3% safety margin, which compares well with the 14.99% actual results. To be sure that the prediction is entirely correct, the thermocouple data are compared as well (Figs. 3-4) [FIGURES 1-4 OMITTED] The measured and predicted temperature results are nearly identical throughout the entire time range (approximately 1.5 hrs.). It appears that the CBUMS-M thermal dataset allows the simulation program to accurately predict the feed performance and the temperature profile in the mold. For comparison purposes, the identical simulation was conducted using the generic chemically bonded mold material dataset. In this case, the generic mold material thermal data give a slightly conservative answer, and the result is a negative safety margin (for a cube that is tightly rigged rig tr.v. rigged, rig·ging, rigs 1. To provide with a harness or equipment; fit out. 2. Nautical a. To equip (a ship) with sails, shrouds, and yards. b. ). The differences between the thermal data have slightly altered the feed prediction result. In general, the predicted versus measured comparison is quite good and would normally be considered to have good agreement. However, for this case, the agreement is even better when the CBUMS-M data are used. Simulations were not conducted using the CBFMS-C and CBSMS-M data because feeding and temperature data were not available to conduct side-by-side comparisons for this configuration using chemically bonded fine core sand or shell molding sand. However, based on the quality of the data and the relative similarity Similarity is some degree of symmetry in either analogy and resemblance between two or more concepts or objects. The notion of similarity rests either on exact or approximate repetitions of patterns in the compared items. to the CBUMS-M thermal data, it can be assumed that these datasets are accurate. Green Sand Mold Materials Comparisons also were made between measurements for the green sand bonded materials (GSMM GSMM or the Good Samaritan Medical Ministry is a non-profit, non-denominational Christian non-governmental organization (NGO) which organizes yearly summer missions to Vietnam. and GS-HPS) and a genetic dataset for green sand bonded mold materials currently available in most simulation software packages. A comparison of the thermal conductivity values revealed that the shape and absolute values are quite different between the generic data and the new GS-MM data. The GS-HPMS has a much higher thermal conductivity than the other green sand datasets. The specific heat data are very similar between the datasets, with the exception of the GS-MM having significantly higher values at temperatures above 1,200C (2,192F). Neither the cause nor the consequences of this difference were evaluated in the study, but it is possible that specific heat values at the higher temperatures may be higher than reality for this molding material. The density curves all show the same trend and are all within about 5% of each other, with the exception of some high density values for the generic dataset at low temperatures. In general, it appears that the density data are very similar between the datasets. The GS-MM and GS-HPMS datasets have not been validated val·i·date tr.v. val·i·dat·ed, val·i·dat·ing, val·i·dates 1. To declare or make legally valid. 2. To mark with an indication of official sanction. 3. using actual metalcasting facility trials so a validation See validate. validation - The stage in the software life-cycle at the end of the development process where software is evaluated to ensure that it complies with the requirements. exercise should first be conducted using simulation and a known casting result to evaluate the predicted feed results when using this new data. Also, some programs require large values of specific heat for green sand materials at approximately the 100C (212F) data point. When inputting the new thermal data, the same specific heat values used previously with the generic dataset for points at 100C must be incorporated. Continuing Studies Accurate thermal data for all aspects of the casting process are required to provide reliable predictions from casting process simulation programs. The mold material genetic thermal data used by most simulation engineers was in need of re-evaluation in order to keep up with advances in simulation technology. The thermal data comparisons show slight differences in thermal conductivity. specific heat and density data between the new data and the genetic datasets. While both sets of data yielded reasonable answers, the new data provides a more accurate prediction. But this research must be continually con·tin·u·al adj. 1. Recurring regularly or frequently: the continual need to pay the mortgage. 2. updated. The coming years promise to provide even more advances in simulation technology, and the mold material thermal data cannot be allowed to lag for 20 years again. Not only that, but work still needs to be done on the current data. The effect of different sand fineness, shape and size distribution, and different binder addition levels on the thermophysical properties needs to lie studied. Also, similar data need to be developed tot non-silica based substrate The base layer of a structure such as a chip, multichip module (MCM), printed circuit board or disk platter. Silicon is the most widely used substrate for chips. Fiberglass (FR4) is mostly used for printed circuit boards, and ceramic is used for MCMs. materials. such as zirconia, chromite chromite (krō`mīt), dark brown to black mineral. It is an iron-chromium oxide, FeCr2O4, with traces of magnesium and aluminum. and olivine olivine (ŏlĭv`ēn), an iron-magnesium silicate mineral, (Mg,Fe)2SiO4, crystallizing in the orthorhombic system. as well as for pure silica for the lost foam process.
Table 1. Sand Samples Tested from Production Metalcasting Facilities
Sand Acronym Description
CBUMS-C Chemically Bonded Urethane Molding Sand-Core (fine)
CBUMS-M Chemically Bonded Urethane Molding Sand-Mold (coarse)
CBUMS-M Chemically Bonded Shell Molding Sand-Mold (coarse)
CBFMS-C Chemically Bonded Furan Molding Sand-Core (fine)
CBFMS-M Chemically Bonded Furan Molding Sand-Mold (coarse)
GS-MM Green Sand-Machine Molded
GS-HPMS Green Sand-High-Pressure Molding Sand
Table 2. New Material Data for CBUMS-M
Temperature Thermal Diff. Density Specific Heat
(C) ([cm.sup.2]/sec) (g/[cm.sup.3]) (J/kg-K)
22 -- 1.488 --
100 0.00474 1.482 1118
200 0.00435 1.475 1114
300 0.00407 1.468 1160
400 0.00388 1.462 1178
500 0.00379 1.456 1196
600 0.00380 1.448 1214
700 0.00389 1.442 1232
800 0.00408 1.437 1250
900 0.00435 1.433 1268
1000 0.00470 1.428 1285
1100 0.00513 1.422 1303
1200 0.00563 1.417 1321
1300 0.00621 1.413 1339
1400 0.00686 1.401 1356
1500 0.00758 1.382 1374
1600 0.00836 1.360 1392
Temperature Therm Cond.
(C) (W/m-K)
22 --
100 0.785
200 0.732
300 0.693
400 0.668
500 0.660
600 0.668
700 0.691
800 0.733
900 0.790
1000 0.863
1100 0.951
1200 1.054
1300 1.175
1400 1.303
1500 1.439
1600 1.582
Table 3. New Material Data for CBFMS-C
Temperature Thermal Diff. Density Specific Heat
(C) ([cm.sup.2]/sec) (g/[cm.sup.3]) (J/kg-K)
22 -- 1.565 --
100 0.00293 1.561 1045
200 0.00303 1.557 1071
300 0.00304 1.553 1096
400 0.00298 1.548 1120
500 0.00290 1.542 1143
600 0.00283 1.535 1167
700 0.00278 1.530 1191
800 0.00279 1.526 1215
900 0.00290 1.522 1238
1000 0.00313 1.518 1262
1100 0.00351 1.512 1285
1200 0.00408 1.508 1309
1300 0.00486 1.503 1333
1400 0.00588 1.498 1356
1500 0.00718 1.493 1380
1600 0.00879 1.488 1404
Temperature Therm Cond.
(C) (W/m-K)
22 --
100 0.478
200 0.505
300 0.517
400 0.516
500 0.511
600 0.507
700 0.507
800 0.517
900 0.547
1000 0.600
1100 0.682
1200 0.805
1300 0.973
1400 1.194
1500 1.479
1600 1.836
Table 4. New Material Data for CBSMS-M
Temperature Thermal Diff. Density Specific Heat
(C) ([cm.sup.2]/sec) (g/[cm.sup.3]) (J/kg-K)
22 0.008561 1.357 790
100 0.007795 1.355 910
200 0.006914 1.354 1015
300 0.006148 1.351 1076
400 0.005497 1.343 1120
500 0.004961 1.335 1154
600 0.00454 1.326 1181
700 0.004233 1.318 1205
800 0.004041 1.312 1225
900 0.003964 1.305 1243
1000 0.004002 1.298 1259
1100 0.004154 1.285 1273
1200 0.004422 1.281 1286
1300 0.004804 1.276 1298
1400 0.0053 1.271 1310
1500 0.005912 1.266 1320
1600 0.006639 1.261 1330
Temperature Therm Cord.
(C) (W/m-K)
22 0.9178
100 0.9614
200 0.9503
300 0.8942
400 0.8269
500 0.7641
600 0.7111
700 0.6721
800 0.6494
900 0.6428
1000 0.6537
1100 0.6796
1200 0.7285
1300 0.7958
1400 0.8822
1500 0.9879
1600 1.1131
Table 5. New Material Data for GS-MM
Temperature Thermal Diff. Density Specific Heat
(C) ([cm.sup.2]/sec) (g/[cm.sup.3]) (J/kg-K)
22 -- 1.404 --
100 0.00413 1.392 953
200 0.00390 1.380 994
300 0.00361 1.367 1035
400 0.00330 1.363 1076
500 0.00298 1.358 1117
600 0.00267 1.352 1158
700 0.00239 1.348 1198
800 0.00216 1.345 1239
900 0.00202 1.342 1280
1000 0.00196 1.339 1321
1100 0.00203 1.335 1362
1200 0.00223 1.332 1403
1300 0.00259 1.329 1444
1400 0.00314 1.326 1485
1500 0.00388 1.323 1526
1600 0.00484 1.320 1567
Temperature Therm Cond.
(C) (W/m-K)
22 --
100 0.548
200 0.535
300 0.511
400 0.484
500 0.452
600 0.418
700 0.386
800 0.360
900 0.347
1000 0.347
1100 0.369
1200 0.417
1300 0.497
1400 0.618
1500 0.783
1600 1.001
Table 6. New Material Data for GS-HPMS
Specific Therm
Temperature Thermal Diff. Density Heat Cond.
(C) ([cm.sup.2]/sec) g/[cm.sup.3] (J/kg-K) (W/m-K)
22 -- 1.395 -- --
100 -- 1.369 1147 --
200 -- 1.350 1152 --
300 -- 1.340 1157 --
400 -- 1.335 1160 --
500 0.00621 1.331 1164 0.962
600 0.00646 1.327 1168 1.001
700 0.00641 1.324 1172 0.995
800 0.00615 1.322 1176 0.956
900 0.00580 1.320 1179 0.903
1000 0.00546 1.318 1183 0.851
1100 0.00522 1.316 1187 0.815
1200 0.00519 1.313 1191 0.811
1300 0.00547 1.313 1194 0.858
1400 0.00616 1.308 1198 0.965
1500 0.00737 1.297 1202 1.149
1600 0.00920 1.286 1205 1.426
Table 7. New Material Data far CBFMS-M
Temperature Density
(C) (g/[cm.sup.3)
22 1.430
100 1.425
200 1.419
300 1.413
400 1.406
500 1.398
600 1.390
700 1.387
800 1.384
900 1.382
1000 1.379
1100 1.376
1200 1.367
1300 1.359
1400 1.351
1500 1.343
1600 1.335
Table 8. New Material Data for CBUMS-C
Temperature Density Specific Heat
(C) (g/[cm.sup.3]) (J/kg-K)
22 1.548 --
100 1.545 1021
200 1.541 1058
300 1.538 1094
400 1.531 1130
500 1.525 1165
600 1.516 1201
700 1.510 1236
800 1.506 1271
900 1.501 1306
1000 1.497 1342
1100 1.491 1377
1200 1.486 1412
1300 1.481 1447
1400 1.476 1482
1500 1.470 1518
1600 1.465 1553
This article was adapted from a paper (02-080) presented at the 2002 Metalcasting Congress. For More Information "Thermal Distortion distortion, in electronics, undesired change in an electric signal waveform as it passes from the input to the output of some system or device. In an audio system, distortion results in poor reproduction of recorded or transmitted sound. of Shell and Nobake Binder Systems," M.J. Keil. J. Rodriguez Rodriguez or Rodrigues (rōdrē`gəs), island (1996 est. pop. 34,883), 42 sq mi (109 sq km), in the Indian Ocean, c.350 mi (560 km) E of Mauritius, of which it is a dependency. , and S.N. Ramrattan AFS A distributed file system for large, widely dispersed Unix and Windows networks from Transarc Corporation, now part of IBM. It is noted for its ease of administration and expandability and stems from Carnegie-Mellon's Andrew File System. AFS - Andrew File System Transactions, 1999. Tony Midea Headline text For a town in Greece see Midea, Greece. Midea (美的電器 Shenzhen Stock Exchange Code 000786; Shanghai Stock Exchange Code 000527) is a Chinese electronics manufacturer located in Shunde, Guangdong. is a product development manager for Foseco Metallurgical met·al·lur·gy n. 1. The science that deals with procedures used in extracting metals from their ores, purifying and alloying metals, and creating useful objects from metals. 2. Inc., Cleveland Cleveland, former county, England Cleveland, former county, NE England, created under the Local Government Act of 1972 (effective 1974). It was composed of the county boroughs of Hartlepool and Teeside and parts of the former counties of Durham and . Midea has helped develop thermal datasets for all of Foseco's global feeding systems products. At the time this paper was originally published, Jiten V. Shah Shah is a Persian term for a monarch (ruler) that has been adopted in many other languages. This term is a Post Islamic Revolution term for monarchs in Iran which is replaced by valie faghih or Supreme Leader. was with K+P Agile ag·ile adj. 1. Characterized by quickness, lightness, and ease of movement; nimble. 2. Mentally quick or alert: an agile mind. , Naperville, Ill. |
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