Question

Consider a low carbon steel allow that has a modulus of resilience of 1.2MPa, an elastic modulus of 200 GPa, and a tensile strength of 800MPa. A series of experiments were done using this alloy and you are asked to analyze some of the obtained data in the following sections:

a). A specimen of this alloy with a rectangular cross section of (15mm x 15mm) and length of 400mm is used in a tensile test. Under an applied tensile stress, this specimen is found to elongate 2mm. On the basis of the information provided here, is it possible to compute the magnitude of the load used to obtain this change in length? If so, calculate the load; if not, explain why.

b). The Charpy impact test data for this alloy is tabulated as follows:

Temperature (degrees C)	Impact Energy (J)
50	212
40	210
30	207
20	190
10	145
0	100
-10	55
-20	20
-30	14
-40	12
-50	10

Plot the data and determine the ductile to brittle transition temperature. From a design view, what would you recommend for service temperatures if the brittle fracture is to be avoided?

Answer 1