Mighty, some ball valves have the ball hard crome plated, this extendeds the life of the valve by decreasing seal wear on the ball itself, creating wire drawing surfaces on the ball and seat seals. In fact I've got one sitting on my desk as a paper weight, where the wear on the ball created a flow channel in the ball, the flow cavitated, creating a larger channel and then when the valve was closed, it still allowed flow. Also, hard chrome plating with the proper seat material will allow for reduced actuator forces required to open or close the valve. This reduces the required actuator sizes and reduces the cost of the valve.
It's always good idea to get the ball hard chrome plated if the process allows for it.
