... copper materials are supplied by Chinalco Luoyang Copper Co., Ltd. that is the best copper supplier in ... we have established long term and steady business cooperation with the main and famous Chinese largest steel ... Group Co.,Dongbei Special Steel Group Co., Ltd.,Daye Special Steel Co.,Ltd.,Xining Special Steel Co., Ltd.,Tiangong International Co., Ltd., etc.,and Tiangong International Co., Ltd. ...