Nucor Corp, the No. 1 U.S. steelmaker by market capitalization, forecast a fall in quarterly profit as cheaper steel imports continue to weigh on average selling prices of the metal. The dollar's strength over the past few quarters has left U.S. steelmakers reeling as cheaper imports from China, the biggest producer of the metal, flood the U.S. market, hurting prices. Imports accounted for about 32 percent of the finished steel market in the first five months of 2015, compared with about 26 percent in the same period last year, Nucor said on Thursday. Demand for Nucor's products from energy markets has also fallen as weak oil prices prompt oil producers to ease back on drilling and idle rigs. The company forecast a profit of 20-25 cents per share for the second quarter ending July 4, well below the average analysts estimate of a profit of 31 cents, according to Thomson Reuters I/B/E/S. It earned 46 cents per share in the same period a year ago. (Reuters)