I was cleaning out an old blacksmith shop the other day and found what I think are filler rod for some kind of welding. They are square rod,2ft long, some are 5/16 sq. and some look like 1/4" sq. They have MOLY cast into one end, and appear to have been made by pouring the metal into a mold, as you can see the divide line where the 2 parts of the mold meet. One of the rods looks like the end was melted at one time. Can anyone fill me in on what they are and how they were used?