Well wrought iron melts at 1500C, brass and bronze around 1700C. And it would take considerable time at those temps so probably not just 1 cast of the spell. Also Burning Hands is a cone, so at those temps anyways it'd assuredly melt stone walls and floors, set fire to the door, roof, and anything else.

Some Object properties: Iron/steel has an AC of 19, irrelevant since it's a Dex save, and a lock has 5hp. But since it's probably immune to fire damage of this temp, the lock may very well be the only thing that remains after Burning Hands sets everything else ablaze. And the door probably has ~18hp, so 1 burning hands won't obliterate it, but the ongoing fire damage after it's set aflame likely would. Though the roof would probably go first.