Engineering, 04.07.2020 14:01 182075

5.A non-cold-worked brass specimen of average grain size 0.01 mm has a yield strength of 150 MPa. Estimate the yield strength of this alloy after it has been heated to 500°C for 1000 s, if it is known that the value of σ0 is 25 MPa.

Answers: 3

Show answers

Answers

Answer from: shazaam1657

97.17 MPa

Explanation:

Given:-

- The nominal strength of the grain, σ0 = 25 MPa

- The average grain size of the brass specimen, d* = 0.01 m

- The yield strength of the non-cold worked specimen, σy = 150 MPa

- Conditions of cold-working: T = 500°C , t = 1000 s

Find:-

Estimate the yield strength of this alloy after cold - working process

Solution:-

- The nominal strength of the grain is a function of yield strength of the material, grain yield factor ( Ky ) and the grain size.

- the following relation is used to determine the grain strength:

σ0 = σy - ( Ky / √( d ) )

- We will use the above relation to determine the grain yield factor ( Ky ) for the alloy as follows. Note: here we will use the average value of grain size:

Ky = ( σy - σy )*√( d* )

Ky = ( 150 - 25 ) * √0.01

Ky = 12.5 MPa - √mm

- Now we will use the cold working conditions of T = 500 C and time of the process is t = 1000 s. We will look up the elongated size of the grain after the cold-working process in lieu with its yield factor ( Ky ). Use figure 7.25.

- The cold-worked grain size with the given conditions can be read off from the figure 7.25. The new size comes out to be d = 0.03 mm.

- We will again use the nominal grain strength relation expressed initially. And compute for the new yield strength of the cold-worked alloy.

σ0 = σy - ( Ky / √( d ) )

σy = σ0 + ( Ky / √( d ) )

σy = 25MPa + ( 12.5 / √( 0.03 mm ) )

σy = 97.17 MPa

- We see that the yield strength of the alloy decreases after cold-working process. This happens because the cold working process leaves with inter-granular strain ( dislocation of planes ) in the material structure which results from the increase in grain size.

Answer from: Quest

No clue sorry. just trying to get points to ask my question

Answer from: Quest

answer:

explanation:

Another question on Engineering

Engineering, 04.07.2019 18:10

The filament of an incandescent lamp has a temperature of 2000k. calculate the fraction of radiation emitted in the visible light band if the filament is approximated as blackbody

Answers: 2

Answer

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

Answer

Engineering, 04.07.2019 18:10

Shafts are machine elements that are used to a) carry axial loads b) direct shear loads c) transmit power d) rotate at constant speed e) none of the above circular and square shafts subjected to the same torque under the same circum behave a) the same way b) almost the same way

Answers: 2

Answer

Engineering, 04.07.2019 18:20

Atank with constant volume contains 2.27 kg of a mixture of water phases (liquid-vapor). in the initial state the temperature and the quality are 127 °c and 0.6, respectively. the mixture is heated until the temperature of 160 oc is reached. illustrate the process in a t-v diagram. then, determine (1) the mass of the vapor in kg at the initial state, (2) the final pressure in kpa.

Answers: 3

Answer

You know the right answer?

5.A non-cold-worked brass specimen of average grain size 0.01 mm has a yield strength of 150 MPa. Es...

Questions