Hi all In the below site link, the meaning of annealing Is " The heating of a die or planchet to soften the metal before preparation of the die or striking of the coin" is this description true ? i think for planchet is true, but not for die. because the die must process the heat treatment for the become harder than befor, not softer. Please guide me about that. May be I mistake http://www.pcgs.com/lingo.chtml
mani, By "die preparation" they are talking about the process during which the die is made, not when it is used to strike coins. When a die is made a hub is pressed into it. This is called 'hubbing'. Before the hub is pressed into the die the die steel must be softened (annealed). When the hub is pressed into the die the die metal becomes 'work hardened' so the die steel must be softened (annealed) again before the next hubbing. In the US dies are now made using the 'single press' hubbing process so the dies do not have to be annealed but once (before being hubbed). After the dies have been hubbed they are hardened and ready to strike coins (after additional preparation work has been completed). Planchets, on the other hand, have been work hardened by the process of being rolled, the blanking process and the process of raising a rim (in the upset mill) and have to be annealed before they are struck by the dies.
All true Hobo. But even after a die is hubbed it is annealed again, usually several more times, and then quenched, in order to strengthen and temper the metal.
