Large diameter concrete corrosion Choji welded steel pipe! ----- Our company specializes in the production of thermal expansion of steel pipe, spiral steel pipe, high-frequency welded pipe, the annual distribution of the posterior wall of Baotou Steel, Tianjin Steel and other steel seamless steel pipe, I plant sided submerged arc welding process in North China's premier, 35 technicians, thermal expansion pipe equipment unit is the unit imported from Germany, the error is small, precise scale. Welcome to come to visit and negotiate.