Please solve the following problems using the hardness data from the Jominy end-quench test for 8660 steel and the data for cooling rates at different locations in round bars during several quenches related to positions along a Jominy bar. 1. For a 8660 steel bar with a 2-inch diameter quenched by mildly agitated oil, please estimate the Rockwell hardness for both the surface and the center of the cross section of the bar. 2. A 8660 steel bar was quenched using mildly agitated molten salt. If it is required that the center of the bar should have a Rockwell hardness of at least 45, what is the maximum value for the diameter of the bar?

Ashielded metal arc-welding operation is accomplished in a work cell by a fitter and a welder. the fitter takes 5.5 min to load components into the welding fixture at the beginning of the work cycle, and 1.5 min to unload the completed weldment at the end of the cycle. the total ength of the weld seams 1200 mm, and the travel speed used by the welder averages 300 mm/min. every 600 mm of seam length, the welding stick must be changed, which takes 0.8 min. while the fitter is working, the welder is idle (resting): and while the welder is working the fitter is idle. (a) determine the average arc-on time as a fraction of the work cycle time. (b) how much improvement in arc-on time would result if the welder used flux-cored arc welding (manually operated), given that the spool of weld wire must be changed every 10 weldments, and it takes the welder 5.0 min to accomplish the change? (c) what are the production rates for these two cases (weldments completed per hour)? attach your work and solutions.