gray iron

Mild steel is a good test, and a light gray iron is admirable for practice lessons.

In this case, as well as in Figs. 32 and 33, both the field and the armature are made of soft gray iron.

At one point, not far from Cle-ellum River, a bed of gray iron ore crosses the magnetic ore at right angles.

An average of over 400 tons of iron is poured daily, and 426 tons of gray iron have been poured in a single day.

The pistons as provided in the A-7 engines are cast from a mixture of steel and gray iron.