Usefully synonyms

Though all true cast iron is brittle, in the sense that it is not usefully malleable, i.e.

We know, in short, that the water is not being usefully employed.

I feel I've spent a couple of hours very usefully.

Usefully Cameron outlines the bribe scenario and what is best to do - here as throughout, it's the voice of experience.

(Tungsten steel and certain classes of manganese steel are malleable only when red-hot.) Normal or carbon steel contains between 0.30 and 2.20% of carbon, enough to make it harden greatly when cooled suddenly, but not enough to prevent it from being usefully malleable when hot.