(a) What is the indentation diagonal length when a load of 0.60 kg produces a Vickers hardness (HV) of 400? (b) Calculate the Vickers hardness when a 700 g load yields an indentation diagonal length of 0.050 mm. (c) An annealed AISI 4340 steel was determine to have a Brinell hardness of HB = 216. Estimate the tensile strength of this steel in MPa.

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Steel balls 12 mm in diameter are annealed by heating to 1150 k and then slowly cooled to 400 k in an air att 325 k and h -20 w/m2 k. assume the properties of the steel to be k- 40 w/m k,p 7800 kg/m3, and cp 600 j/kg k. a. determine whether lumped system method can be used to analyze this problem and if so why" b. determine the time required for the cooling process. c. determine the total amount of heat lost from each ball to the ambient air