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As an intern on the shop floor of your engineering firm, you are asked to come up with a makeshift door handle for a furnace. When the furnace is in operation, the external surface of the door is approximately 160°C. You search the scrap metal bin and find some sort of carbon steel rod that you believe you can bend into a U-shape and weld to the outer door surface. The rod is 50 cm long with a 6 mm diameter. There is negligible contact resistance through the weld joint and surrounding air at 24°C will cool the handle (h = 15 W/m².K). a) You know that attaching a metal rod to a hot object might cause someone to get burned, so in analyzing your handle you want to be as cautious as possible. Since you don't know what kind of carbon steel you have found, you will have to estimate its relevant properties. Choose properties of the carbon steel from Table A.1 that will ultimately predict the largest handle temperatures during analysis. b) What is the coolest temperature of the handle? c) How close to the door can you grasp the handle without getting burned if Tburn = 65°C?

As an intern on the shop floor of your engineering firm, you are asked to come up with a makeshift door handle for a furnace. When the furnace is in operation, the external surface of the door is approximately 160°C. You search the scrap metal bin and find some sort of carbon steel rod that you believe you can bend into a U-shape and weld to the outer door surface. The rod is 50 cm long with a 6 mm diameter. There is negligible contact resistance through the weld joint and surrounding air at 24°C will cool the handle (h = 15 W/m².K). a) You know that attaching a metal rod to a hot object might cause someone to get burned, so in analyzing your handle you want to be as cautious as possible. Since you don't know what kind of carbon steel you have found, you will have to estimate its relevant properties. Choose properties of the carbon steel from Table A.1 that will ultimately predict the largest handle temperatures during analysis. b) What is the coolest temperature of the handle? c) How close to the door can you grasp the handle without getting burned if Tburn = 65°C?

Elements Of Electromagnetics
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
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Metal Aluminums Pure 99% pure Duralumin (4% Cu, 0.5% Mg) Alloy 6061-T6 Alloy 7075-T6 Chromium Cupreous metals Pure Copper DS-C15715* Beryllium copper (2.2% Be) Brass (30% Zn) Bronze (25% Sn) Constantan (40% Ni) German silver (15% Ni, 22% Zn) Gold Ferrous metals Pure iron Cast iron (4% C) Steels (Cs 1.5%)|| AISI 1010¹t 0.5% carbon. 1.0 % carbon 1.5% carbon. Properties at 20°C k P Cp (kg/m³) (J/kg-K) (W/m-K) (10-5 m²/s) -170°C -100°C 2,707 2,787 2,700 2,800 7,190 8,954 8,900 8,250 8,618 19,320 905 7,897 7,272 883 8,522 385 8,666 343 8,922 410 896 841 453 384 384 420 394 129 447 420 7,830 434 7,833 465 7,801 473 7,753 486 237 211 164 167 130 90 398 365 103 109 26 22 25 318 80 52 64 54 Table A.1 Properties of metallic solids. 43 36 (X 9.61 6.66 6.90 5.52 2.77 11.57 10.7 2.97 3.32 0.86 0.61 0.73 12.76 2.26 1.70 1.88 1.47 1.17 0.97 302 220 k and a for carbon steels can vary greatly, owing to trace elements. tt 0.1% C, 0.42% Mn, 0.28% Si; hot-rolled. 76 158 483 73 17 18 327 132 242 206 126 100 120 420 89 19 19 324 98 70 0°C 100°C 200°C 300°C 400°C 236 209 164 166 121 95 401 367 106 22 24 319 84 65 55 Thermal Conductivity, k (W/m.K) 43 36 * Dispersion-strengthened copper (0.3% Al2O3 by weight); strength comparable to stainless steel. $ Conductivity data for this and other bronzes vary by a factor of about two. 240 182 172 137 88 391 355 117 133 26 31 313 72 61 52 43 36 238 234 194 177 172 85 389 345 143 35 40 306 63 55 48 42 36 180 177 82 384 335 146 45 299 56 50 45 40 35 228 77 378 320 147 48 293 50 45 42 36 33 600°C 215 69 366 279 39 36 35 33 31 800°C 1000°C 95 (liq.) 64 62 352 336 264 249 30 29 31 29 28 29.5 29 28 28
Transcribed Image Text:Metal Aluminums Pure 99% pure Duralumin (4% Cu, 0.5% Mg) Alloy 6061-T6 Alloy 7075-T6 Chromium Cupreous metals Pure Copper DS-C15715* Beryllium copper (2.2% Be) Brass (30% Zn) Bronze (25% Sn) Constantan (40% Ni) German silver (15% Ni, 22% Zn) Gold Ferrous metals Pure iron Cast iron (4% C) Steels (Cs 1.5%)|| AISI 1010¹t 0.5% carbon. 1.0 % carbon 1.5% carbon. Properties at 20°C k P Cp (kg/m³) (J/kg-K) (W/m-K) (10-5 m²/s) -170°C -100°C 2,707 2,787 2,700 2,800 7,190 8,954 8,900 8,250 8,618 19,320 905 7,897 7,272 883 8,522 385 8,666 343 8,922 410 896 841 453 384 384 420 394 129 447 420 7,830 434 7,833 465 7,801 473 7,753 486 237 211 164 167 130 90 398 365 103 109 26 22 25 318 80 52 64 54 Table A.1 Properties of metallic solids. 43 36 (X 9.61 6.66 6.90 5.52 2.77 11.57 10.7 2.97 3.32 0.86 0.61 0.73 12.76 2.26 1.70 1.88 1.47 1.17 0.97 302 220 k and a for carbon steels can vary greatly, owing to trace elements. tt 0.1% C, 0.42% Mn, 0.28% Si; hot-rolled. 76 158 483 73 17 18 327 132 242 206 126 100 120 420 89 19 19 324 98 70 0°C 100°C 200°C 300°C 400°C 236 209 164 166 121 95 401 367 106 22 24 319 84 65 55 Thermal Conductivity, k (W/m.K) 43 36 * Dispersion-strengthened copper (0.3% Al2O3 by weight); strength comparable to stainless steel. $ Conductivity data for this and other bronzes vary by a factor of about two. 240 182 172 137 88 391 355 117 133 26 31 313 72 61 52 43 36 238 234 194 177 172 85 389 345 143 35 40 306 63 55 48 42 36 180 177 82 384 335 146 45 299 56 50 45 40 35 228 77 378 320 147 48 293 50 45 42 36 33 600°C 215 69 366 279 39 36 35 33 31 800°C 1000°C 95 (liq.) 64 62 352 336 264 249 30 29 31 29 28 29.5 29 28 28
As an intern on the shop floor of your engineering firm, you are asked to come up with a makeshift door handle for a furnace. When the furnace is in operation, the external surface of the door is approximately 160°C. You search the scrap metal bin and find some sort of carbon steel rod that you believe you can bend into a U-shape and weld to the outer door surface. The rod is 50 cm long with a 6 mm diameter. There is negligible contact resistance through the weld joint and surrounding air at 24°C will cool the handle (h = 15 W/m² · K). a) You know that attaching a metal rod to a hot object might cause someone to get burned, so in analyzing your handle you want to be as cautious as possible. Since you don't know what kind of carbon steel you have found, you will have to estimate its relevant properties. Choose properties of the carbon steel from Table A.1 that will ultimately predict the largest handle temperatures during analysis. b) What is the coolest temperature of the handle? c) How close to the door can you grasp the handle without getting burned if Tüurn 65°C?
Transcribed Image Text:As an intern on the shop floor of your engineering firm, you are asked to come up with a makeshift door handle for a furnace. When the furnace is in operation, the external surface of the door is approximately 160°C. You search the scrap metal bin and find some sort of carbon steel rod that you believe you can bend into a U-shape and weld to the outer door surface. The rod is 50 cm long with a 6 mm diameter. There is negligible contact resistance through the weld joint and surrounding air at 24°C will cool the handle (h = 15 W/m² · K). a) You know that attaching a metal rod to a hot object might cause someone to get burned, so in analyzing your handle you want to be as cautious as possible. Since you don't know what kind of carbon steel you have found, you will have to estimate its relevant properties. Choose properties of the carbon steel from Table A.1 that will ultimately predict the largest handle temperatures during analysis. b) What is the coolest temperature of the handle? c) How close to the door can you grasp the handle without getting burned if Tüurn 65°C?
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