Air Carrier Captain requested a different track from Dispatch to avoid severe turbulence over the North Atlantic and was denied. Six minutes of severe turbulence was encountered near 66N and 50W; resulting in an aircraft inspection upon arrival.

Narrative

Concerning the turbulence report on our track at 6650N; I called Dispatch to ask about a reroute. I was told we would be on the northern edge and a company flight would be 30 minutes in front on the same route. After 15 minutes; Dispatch called and told me the new route would add 47 minutes. We discussed the situation and I was told again that we should pass north so we continued on the original route to make an on time arrival. As we approached 6650N; all aircraft in the area were warning other aircraft of severe turbulence. We immediately sent a message to Dispatch. The Dispatch wanted to know how we knew there was severe turbulence. Aircraft in the area had reported severe turbulence to Iceland Radio at that time. We called the company flight for a report but he was at 68N; not on our reroute. We then asked for a reroute north. By the time the reroute arrived we hit the area of turbulence. It lasted 6 minutes; plus or minus 25 knots; 200 FT altitude deviations; full throttle deflections; VMO twice with throttles at idle with a couple of severe jolts. All Flight Attendant's were seated; seatbelt signs on and everything stored safely. There were only a few spilled glasses. In summary; I feel we are more concerned about on time arrival than safety. Time and time again we are dispatched through turbulent areas on flight plans for the most efficient route. This time we had enough warning to prepare the cabin but it brought about a time consuming; costly inspection.