Bissoy
Login
Get Advice on Live Video Call
Earn $ Cash $ with
consultations on Bissoy App
In order to double its yield strength, the grain size of a steel of ASTM grain size number 2 should be changed to ASTM grain size number (neglect friction stress)
A
1
B
4
C
6
D
8
Correct Answer:
6
Examine the following statements :
i) Factor of safety for steel should be based on its yield stress,
ii) Factor of safety for steel should be based on its ultimate stress,
iii) Factor of safety for concrete should be based on its yield stress,
iv) Factor of safety for concrete should be based on its ultimate stress.
The correct statements are
A
(i) and (iii)
B
(i) and (iv)
C
(ii) and (iii)
D
(ii) and (iv)
Identify the correct statements from the following:
P. 0.2% yield strength of a material implies 0.2% of the yield strength.
Q. Von-Misses yield criterion implies that yielding occurs when the distortion energy reaches a critical value.
R. Radius of the cylinderical Von-Misses yield surface increases as the grain, size of a single phase material decreases.
S. Tresca's yield criterion gives a circular cylinderical surface in the space of the three principal stresses.
A
P, Q
B
Q, R
C
P, R
D
Q, S
If a steel having ASTM grain size number 5 have transition temperature equal to 20 degrees. For the same steel having ASTM grain size 10, the DBTT will be equal to __________
A
20
B
50
C
-50
D
Cannot predict
If the specimen is deformed plastically beyond the yield stress in one direction, e.g., tension and then after unloading it is loaded in the opposite direction, e.g., compression, it is found that the yield stress is less than the original yield stress. This dependence of yield stress on direction loading is called ____________
A
bauschinger effect
B
strain hardening
C
residual stress
D
nabarro–herring effect
The largest size of immobilised segment of dislocation in a Frank Read (FR) source contained in a polycrystalline material is of the order of grain size. In a metal of 10 μm grain size, the shear stress required to operate such a FR source is 100 MPa. If the grain size in the same metal is reduced to 10 μm, the shear stress required to operate such FR source would be . . . . . . . . MPa.
A
10<sup>2</sup>
B
10<sup>3</sup>
C
10<sup>5</sup>
D
10<sup>6</sup>
An ASTM grain size determination is being made from a photomicrograph of a metal at a magnification of 1X. What is the ASTM grain size number of the metal if there are 992 grains per square mm?
A
6
B
7
C
7.92
D
8.91
The yield strength of a material is 200MPa when the grain size is 80 micron. If the frictional stress is 80MPa, find the strength when the grain diameter is 160 micron?
A
100 MPa
B
150MPa
C
250MPa
D
180 MPa
Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, $$\sigma $$ = yield strength and E = modulus of elasticity)
A
E
B
$$\sigma $$
C
$$\frac{\sigma }{{\text{E}}}$$
D
$$\frac{{\text{E}}}{\sigma }$$
Tresca or maximum-shear stress criteria assumes that yielding occurs when the maximum shear stress reaches a value of the shear stress in the uniaxial tension test. Assume the principal stress being σ1, σ2, σ3 where σ1 is largest, and σ3 is the smallest principal stresses. Find the value of minimum shear stress to cause yielding, given that yield stress in tension is equal to σo?
A
τ = σo
B
τ = σo/2
C
τ = σo/3
D
τ = σo/4
The design yield stress of steel according to IS: 456-1978 is (where fy is the characteristic yield strength of steel)
A
0.37 fy
B
0.57 fy
C
0.67 fy
D
0.87 fy