A new meat-processing plant has opened and utilizes an overhead conveyor to move sides of beef (weighing approximately 300 pounds each) through the operation. The sides are suspended on hooks, which are spaced along the conveyor chain. Within the first several weeks of operation, several of the hooks broke, resulting in a 300-pound section of beef dropping from overhead. Most of the fractures occurred shortly after a particular side of beef exited the freezer unit and begun its journey through the plant. The freezer temperature is approximately 0°F, and the hooks have been made from a low-carbon, plain-carbon steel.
a. What do you suspect is the cause of these failures?
b. What recommendations would you make regarding the failing hooks? If replacement is recommended, what material would you suggest as a better alternative?
c. Do metallurgical features play a role? Consider grain size, microstructure (i.e., heat treatment), and the type, orientation, and distribution of possible impurities.