3.5NI钢物性.doc

Unless otherwise stated this page contains Version 1.0 content (Read more about versions)2.3.7 Thermal conductivitiesDefinition and unitsThe thermal conductivity, , of a substance may be defined as the quantity of heat transmitted, Q, due to unit temperature gradient, in unit time under steady conditions in a direction normal to a surface of unit area, when the heat transfer is dependent only on the temperature gradient. = QTnIn this section thermal conductivity values are assembled for metallic, semi-conducting and insulating elements, representative groups of alloys, refractories and miscellaneous constructional and insulating materials, some liquids and some gases. The values are expressed in the SI unit W m1 K1 throughout. Factors for converting to other units are as follows:1 W m1 K1 = 0.01 J cm cm2 s1 K1= 0.002 388 cal cm cm2 s1 K1= 0.859 8 kcal m m2 h1 K1= 0.001 926 Btu in ft2 s1 F1= 6.933 Btu in ft2 h1 F1= 0.577 8 Btu ft ft2 h1 F1= 0.000 160 5 Btu ft ft2s1 F1More extensive collections of thermal conductivity data will be found in Touloukian et al. (1970a, b and c).Thermal conductivities of metallic elementsThe thermal conductivity values in the table below are for metallic elements in the purest polycrystalline condition for which reliable measurements have been reported. Entries in italics relate to the liquid phase.The thermal conductivities of less pure samples of these elements will be lower than the values given below. Thermal conductivity invariably decreases with decreasing purity; such dependence being weak at ambient and higher temperatures but very strong at cryogenic temperatures./(W m1 K1)MetalTemperature/K173.2273.2373.2573.2973.2Aluminium24123624023392Antimony3325.5221927Beryllium36721816812993Bismuth118.27.21317Cadmium10097958945Caesium37362020.617.7Cerium8111316Chromium12096.5928266Cobalt130105896953Copper420403395381354Dysprosium910.5Erbium1415Gadolinium1210Gallium43413345Gold324319313299272Hafnium2523222121Holmium141617Indium92847642Iridium156147145139Iron9983.5725634Lanthanum121314.5Lead3736343221Lithium9486824759Lutetium1817Magnesium160157154150Manganese78Mercury29.57.89.411.7Molybdenum145139135127113Nickel11394836771Niobium5353555864Osmium93888787Palladium7272737993Platinum7372727378Plutonium468Potassium105104534532Praseodymium9.91213.4Rhenium5249474445Rhodium156151147137Rubidium5958322922Ruthenium12311711510898Samarium10131314Scandium1516Silver432428422407377Sodium141142887860Tantalum58575858.560Technetium515050Terbium1110.5Thallium514744Thorium5554545658Thulium1617Tin7668633240Titanium2622211921Tungsten188177163139119Uranium2427293343Vanadium3231313338Yttrium16.517Zinc11711711210466Zirconium2623222123 Values for the a-axis which approximate to the polycrystal; those for the b-axis are 91 and 88 and for the c-axis are 16.5 and 16 at 173.2 and 273.2 K. Thermal conductivities of single crystals of some non-cubic metals at normal temperature/(W m1 K1)MetalThermal conductivity in direction of c-axisa-axisb-axisBismuth5.49.3Cadmium83.05104Dysprosium11.6510.25Erbium18.412.6Gadolinium10.710.3Gallium16.040.888.3Holmium22.113.6Lutetium23.313.8Mercury (at 227.7 K) 33.025.9Terbium14.59.45Thulium24.214.1Tin51.874.0Thermal conductivities of alloysAt low temperatures the thermal conductivity of a given metal tends to increase in proportion to the reciprocal of its residual resistivity 0. Many metals, especially good electrical conductors, have thermal conductivities that follow the simple relation = L0Tat very low temperatures and at temperatures higher than their Debye temperature; L0 being the Lorentz coefficient 2.45 108 W s1 K2, the electrical conductivity in S m1 and T the absolute temperature. This behaviour enables the thermal conductivities of metallic samples to be estimated fairly reliably from simple electrical resistivity measurements.As the thermal conductivities of alloys depend strongly on their mechanical and thermal history (heat treatment) as well as on their chemical composition, the values tabulated below should be regarded as typical for the compositions listed. For many groups of alloys the thermal conductivity of a particular sample, near room temperature and above, can be estimated within about 6% from its more easily measured electrical conductivity using the relation = LT + C. The optimum values for L and C for different alloy types are as follows:Main constituent metal L/(108 W s 1 K2)C/(W m 1 K1)Aluminium.2.2210.5Copper.2.397.5Alpha-iron.2.439.2Gamma-iron.2.394.2Magnesium.2.219.6Nickel.2.138.4Nickel-chromium (nimonic type) .2.206.0Titanium.2.302.9Zirconium.2.502.2For more detailed information on the relationship between the thermal and electrical conductivities of alloys see: Powell (1965), Hust and Clark (1971).Thermal conductivities of alloys at ambient and elevated temperaturesAlloyComposition / weight percent / (W m1 K1) at Temperature / KAlCCrCuFeMgMnNiSiWZnOther2733735737739731273Aluminium alloysAluminium100 236240233Alpax gamma870.30.30.312188188184Lo-Ex8510.50.9111.8172175173Y-alloy923.80.41.31.80.4180188194RR 59932.31.21.51.20.9168176186RR 57892.20.32.50.50.35161171178Copper alloysCopper100403395381354Brass7030106128146Bronze9010 Sn536080German Silver621522232945Constantan6040222427Manganin841242126Nickel alloysNickel10094836771Alumel22951303235Monel0.229.21.70.11.067.121243043Chromel P10 901923Nichrome0.121 0.60.6577.30.413141721Inconel 6000.1160.380.5740.414.615.819.122.125.7Inconel X-7500.80.04150.056.80.7730.32.5Ti, 0.8 Nb11.313.016.520.123.627.9Incoloy 8000.40.05210.51330.70.4 Ti11.312.816.419.422.831Incoloy 8020.3210.51330.411.313.116.219.222.126Hastelloy R-23520.1615.51016215.5 Mo, 2.5 Co11.714.817.62025.5Nimonic 750.30.1200.551bal1.02 Co, 0.3 Mo, 0.2 Ti13.917.521.024.3Nimonic 801.50.07200.211bal1.02 Co, 0.3 Mo, 2 Ti12.115.518.423.5Nimonic 901.50.07200.211bal1.517 Co, 0.3 Mo, 2 Ti13.016.520.023.7Nimonic 1054.50.1414.50.211bal1.020 Co, 5 Mo, 2 Ti11.614.717.421.227.6Carbon steels0.08 C, 0.3 Mn0.080.045bal0.310.070.08595849 4032280.23 C, 0.6 Mn0.230.13,0.640.070.115251463932270.42 C, 0.6 Mn0.420.12,0.640.060.115251463830270.8 C, 0.2 Mn0.840.02,0.240.135149423631271.2 C, 0.35 Mn1.220.110.08,0.350.130.164545403528260.2 C, 1.5 Mn0.230.060.10,1.510.040.12464643373127Low alloy steels0.3 C, 1 Cr0.321.090.07bal0.70.070.204946423629280.4 C, 1 Cr, 0.3 Ni0.350.880.12,0.60.260.214343413631280.2 C, 0.6 Ni, 0.5 Mo0.20,1.350.60.250.5 Mo37383734290.3 C, 0.2 Cr, 3.5 Ni0.330.170.08,0.553.470.183638383428280.3 C, 1 Cr, 3.4 Ni0.330.800.05,0.533.380.173436373529280.4 C, 1 Cr, 3.6 Ni0.40.8,0.663.60.2333637.535280.3 C, ! Cr, 3.5 Ni0.340.780.05,0.553.530.273334363428280.5 C, 1 Mn, 2 Si0.490.040.09,0.90.162.0252831312826High alloy steels1.2 C, 13 Mn1.220.03bal13.00.070.221315182123260.3 C, 28 Ni0.280.03,0.928.40.151315182123284 Cr, 18 W, 1 V0.724.260.06,0.250.070.3018.51 V242628282728Kovar0.02540.472917 Co14.114.715.617.519.3Stainless steels304, 321, 3470.0517.5bal29114.516.52022.525.529.53160.0517,21212.5 Mo13.51518.521.52428.53100.124,22011213.517.520.52316 Cr, 20 Ni0.0116,1.2200.313.615.718.921.523.826.8Era-ATV0.515,1.2271.32.81112.515.521.5403, 405, 4090.112,21252627430, 4340.0517,211 Mo22.222.923.724.4410, 4200.3130.1,0.50.50.423.624.626.328Miscellaneous alloysPlatinum 90%, iridium 10%.31Platinum 90%, rhodium 10% .38Platinum 60%, rhodium 40% .46515869Titanium 92.5%, aluminium 5%, tin 2.5% .78.310.5Titanium 96%, aluminium 2%, manganese 2% .9.310.510.7Zirconium 93.1%, tin 6.7%, carbon 0.1% .8.712Zirconium 97.5%, tin 2.3%, carbon 0.1% .11.313Thermal conductivities of alloys used in low temperature applicationsAlloy/(W m1 K1)Composition/weight percentTemperature/KAlCCrCuFeMgMnNiSiSnZnOther273.217310050204Aluminium alloysAluminium99.9922829587041001075(1 C) 1100-0bal10.050.051.00.0520522831522545(N3) 3003 F,0.121.217015814311758112219 T81,6.30.020.30.200.1118684626(N8) 5083 0,0.150.14.50.70.40.25110926639173.37039 T61,0.20.12.80.250.2415096643014.7Copper alloysCopper99.96400480123037001450ETP Cu99.953954458801320325OFHC Cu99.95400460750900200Brass7030106927045214Brass653511359Cupro-nickel901031141German Silver6215222320Copper Beryllium982 Be24102Nickel alloysNickel99.9994115154320865138Inconel X0.90.041570.7730.32.5 Ti11.4108.7K. Monel30.153010.6650.15171412Hastelloy X0.152224459 Mo9.986.5530.5Inconel 718 0.40.0418.618.51 Ti, 5 Nb, 3 Mo108.774.82.60.4SteelsArmco iron0.0299.80.037683.69510965132.5% Ni 0.1bal0.82.50.238333.5% Ni0.1,0.83.50.23429215% Ni 0.1,0.850.231261