Quenching is a rapid cooling process by which many metallic alloys are hardened. Brass (a copper alloy: 70 Cu, 30 Zn) plates that are 4 mm thick are quenched in a water bath at a heat treating plant. If a brass plate is initially at 4500C determine the quench time needed for the plate to attain 900C. The water bath temperature is 800C and has an average convective heat transfer coefficient of 45 W/(m2 K), determine how long the plate has to remain in the oven.

Q: A very thick slab with thermal diffusivity 5.6x10-6 m2/s and thermal conductivity 20 W/m.K js…

A: Given, x→0 to0.45 mt=3 min or 180 sα=5.6×10-6 m2/sk=20 W/mKh=100 W/m2K

Q: How long does it take to achieve a center temperature of 50 °C?

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Q: In general, it is helpful to think of a thermally lumped object as being "tied down" to some…

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Q: A long copper cylinder 0.6 m in diameter and initially at a uniform temperature of 38oC is placed in…

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Q: 4- (Transient heat conduction) Stainless-steel ball bearings (k = 22.2 W/m K, a = 4.85 x 10-6 m 2…

A: Given data from the question as below: D = 20mm = 0.02 m Ti = 850 oC T∞ = 40oC h = 600 W/m2K Tr,t…

Q: An industrial process to harden ball bearings involves quenching them in a cooling bath at 40°C. The…

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Q: Ground cherry seeds need to be planted at a depth of 1-cm below the surface and will only germinate…

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Q: In a quenching process, a copper plate of 3 mm thick is heated up to 350°C and then suddenly, it is…

A: Explanation: first Bi number is calculated to check the validity of lumped analysis which must be…

Q: ., In a certain experiment, cylindrical samples of diameter 4 cm and length 7 cm are used (see Fig.…

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Q: m²/s) In an annealing process, a 50-mm-thick stainless steel plate (p=8238 kg/m³, cp=468 J/kg-K,…

A: Introduction The Biot number and Foriure number will be used in this issue to determine how long it…

Q: An aluminium panel, thickness 1.8 mm and initial temperature 293 K, is to be heat treated by…

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Q: 4) In a tempering process, glass plate, which is initially at a uniform temperature Ti, is cooled by…

A: (a) At the mid plane of the plate, write the temperature variation. θ0=T0-TsTi-Ts=0.50=C1e-λ12F0In…

Q: How long must a 0.4 cm cylindrical copper fin be if the temperature of its insulated tip exceeds the…

A: Find the attachment for the solution.

Q: The thermal conductivity of a sheet of rigid, extruded insulation is reported to be k = 0.029 W/m-K.…

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Q: In many manufacturing plants, individuals are often working around high temperature surfaces.…

A: We haveTavg=Tin+Tout2Tavg=597+472Tavg=322°CTavg=322°C+273KTavg=595 KNow form table A-3cp for carbon…

Q: A steel sphere (AISI 1010), 100 mm in diameter, is coated with a dielectric material layer of…

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Q: Write clearly and explain.

A: Understand that the uniform heat generated is one-dimensional, steady-state conduction. Write the…

Q: à long insulated tube is doped with an exothermic ma- erial which generates steady and uniform heat…

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Q: Required information Consider a very long, slender rod. One end of the rod is attached to a base…

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Q: Consider a 1 cm thick copper wall (k=375 W/m K) whose one surface is exposed to condensing water…

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Q: Show that the plate is lumped, and then find the time required for the plate to achieve a…

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Work and Heat Transfer

It is generally related to thermal engineering which tells about the use, creation, conversion and transfer of heat energy between the systems. It is also considered that to transfer heat from one source to another, transfer of masses is also required. There are various mechanisms by which, transfer of heat takes place i.e. thermal conduction, convection, radiation or by change of phase. All these mechanisms have their own specific features which sometimes occur simultaneously within the same system.