Nucor (NYSE:NUE) says it expects a challenging steel market to weigh on its second-quarter profit, sending its shares lower Wednesday morning. The Charlotte, N.C.-based steel manufacturer sees earnings for the three months ending June 30 in the range of 35 cents to 40 cents a share, including a $30 million charge related to its Duferdofin Nucor joint venture. Excluding the impairment charge, Nucor anticipates a profit that's below the 94 cents it earned in the second-quarter of 2011. Instead, it says profit will be closer to the 46 cents a share it earned last period. Analysts in a Thomson Reuters poll are looking for a profit of 56 cents. Nucor said operating performance at Duferdofin Nucor has been "well below budgeted levels" through the first half of the year and the recently escalated turmoil in Europe has hampered steel demand. The company also attributed declines to a surge in imports, particularly of rebar, plate and sheet steel, that began at the end of 2011 and continue today.