On May 21, Valin Liangang began to produce the third batch of galvalume sheet in 2.0mm thick, the thickest gauge of such material used in the market. As of May 25, through strengthened examination on annealing furnace and hydrogen content inside the furnace, the producer had rolled out 2,863.28 tons of first-grade galvalume sheet, up 7.7 percentage points than last month in terms of first-grade ratio.