They are processing iron bars at the factory.
My mother rolled out the pie dough with a rolling pin.
Standard kanji spelling for both a metal bar and a rolling pin.
Variant spelling; less common but still encountered.
延べ (nobe, 'stretching, rolling') + 棒 (bō, 'stick, bar'). The word literally means a bar made by stretching or rolling, hence both a metal bar and a rolling pin.