How does the speed of sound in steel or aluminum compare with the speed of sound in air?

typical sound velocities (longitudinal waves) in different materials:

air 343 m/s

aluminium alloyed 6380 m/s

aluminium unalloyed 6320 m/s

aluminium oxide 9000-9850 m/s

steel (austenitic) 5650-5850 m/s

steel (ferritic) 5920 m/s

steel casting 5730 m/s