Not only they would be literally cooked going near vents, the vents would be useless. Smelting and smithing require that you control the temperature, at the very least keep it stable. Vents aren't like that. Vents also aren't hotter than 500° Celsius, and bronze needs 913°, while iron needs 1538°.
That's why you either breed your weapons and equipment out of animals like scaly foots, seashells and any other creature with hard parts that can be domesticated into armor and piercing weapons. So your speartip is going to be a very pointy seashell, perhaps with the molusc still inside. This just requires the same process that turned a near useless grass into corn.
Or you use electricity. Electrometallurgy is what allowed us to make aluminum be so cheap and abundant as it is. You domesticate eels, and use them, either alive or dead, to separate water in oxygen and hydrogen, and then making 2800 °C oxyhydrogen blowtorches. You don't even need the eels. Seawater, an electrolyte and a few other components can become primitive batteries.
Btw, you might want the nodules in the ocean floor, but instead of mining iron, lead and other metals, just breed sponges, or maybe fishes, that filter it from seawater. For example, a kilogram of iron can be harvested by filtering 50,000 m3 of ordinary seawater. The liquid volume involved is only about as much as a single shark breathes in a month. Or use some magnetic lodestones.