... copper materials are supplied by Chinalco Luoyang Copper Co., Ltd. that is the best copper supplier in China ... purity is 99.9%min. we have established long term and steady business cooperation with the main ... 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. always ...