Carbon and aluminum forks and frames can NOT be repaired if a tube is cracked or broken. They are like stale pretzels. They don't bend. They don't flex. They simply fail when heavily stressed. The factory might be able to replace a cracked carbon tube, but the cost would be very high.

High quality steel frames and forks don't crack or break under the stress of a typical crash. Steel will simply bend a bit.

Any good bike shop can realign a steel fork that is a bit off kilter after a crash. I paid $40 to get a fork realigned last year. If a steel tube got loose at a joined area after a crash, there are many frame builders who could rejoin the tube for moderate cost (under $100 if the tubes are not damaged). I've never seen a top quality steel frame come apart though.