True, you must keep ALL weld spatter off the chrome bar, i used an old cardboard cylinder and cut it down the side to slip over the bar to protect it. As for heat, i have been told that if you get it hot not to quench it but to let it cool on its own. For the purpose of a ram rod i can't see any problems quenching it as you weld, as chilling it can harden the metal which for this is not a bad thing. Either way, the people at the machine shop that will be doing the work will know what their doing (well i hope they do!).
The only problem i can see, is when you get the new parts welded on is they must be straight! when i did mine, i had the ram attached to the machine and welded the rod to the pivot point while it was still attached to the bobtach. This way its in perfect allignment! I saw the bobtach on a block of wood and extended the chrome bar untill it was where i needed it, covered the rod and proceeded to lay a nice weld to it. Make sure the person thats welding it knows NOT to run the weld up the stick, as there is not much room between the eye on the end of the stick and the gland nut on the ram, you don't want it rippng your wiper seal apart when you pull the ram back! I had a 4 in one like that, a big ugly weld that went too far down and tore the top off the gland nut and killed the wiper seal.