subject
Engineering, 19.10.2019 00:30 barstr9146

The outer surface of an steel alloy is to be hardened by increasing its carbon content. the carbon is to be supplied from an external carbon-rich atmosphere, which is maintained at an elevated temperature. a diffusion heat treatment at 826°c for 10 min increases the carbon concentration to 0.83 wt% at a position 1.3 mm below the surface. estimate the diffusion time required at 610°c to achieve this same concentration also at a 1.3 mm position. assume that the surface carbon content is the same for both heat treatments, which is maintained constant. the preexponential and activation energy values for the diffusion of carbon in the iron are 8.3 × 10-8 m2/s and 78.5 kj/mol, respectively.

ansver
Answers: 2

Another question on Engineering

question
Engineering, 03.07.2019 15:10
Heat is added to a piston-cylinder device filled with 2 kg of air to raise its temperature 400 c from an initial temperature of t1 27 cand pressure of pi 1 mpa. the process is isobaric process. find a)-the final pressure p2 b)-the heat transfer to the air.
Answers: 1
question
Engineering, 04.07.2019 18:10
Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?
Answers: 1
question
Engineering, 04.07.2019 18:10
The thermal expansion or contraction of a given metal is a function of the f a)-density b)-initial temperature c)- temperature difference d)- linear coefficient of thermal expansion e)- final temperature f)- original length
Answers: 2
question
Engineering, 04.07.2019 18:20
What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.
Answers: 3
You know the right answer?
The outer surface of an steel alloy is to be hardened by increasing its carbon content. the carbon i...
Questions
Questions on the website: 13722367