Possibly a foreign article stuck inside the drum. When the machine goes onto spin this can rub against the outer drum causing such a sound.

This is commonly the underwire from a bra that has worked loose and lodged in one of the holes inside the inner drum. Have a careful feel round the whole inner surface of the drum to see if you can detect anything protruding. If you find a wire, grip it with a good pair of pliers and try to pull it out, remembering the shape that it probably has so it will need to be coaxed out accordingly. Anything protruding through the holes doesn't belong there!

I have removed three of these from our washing machine!